Chia, Hemp, Perilla and Walnut Oils

Q: What are chia, hemp, perilla and walnut oils?

They are oils pressed from chia seeds, hemp seeds, perilla seeds and walnuts. All four supply ALA, a plant omega-3 fat, and are rich in polyunsaturated fat.

Q: Which has the most ALA?

Chia oil is described as up to 60% ALA and perilla oil as high in ALA. Hemp seed oil was 9.8 to 14.4% ALA in three samples. Walnut oil gives 1.4 g of ALA per tablespoon, against 7.3 g for flaxseed oil (Linus Pauling Institute).

Q: Are they as good as fish oil?

No evidence says so. The body turns only part of ALA into EPA and little into DHA, and experts disagree on whether that is enough. No trial of these oils tested a swap for fish or algae oil.

Q: Do they lower cholesterol?

Walnut oil lowered cholesterol and LDL in a 100-person trial in type 2 diabetes, and chia oil did so in a 75-woman trial in obesity. Each is a single trial of blood markers.

Q: Do they help skin, gut or mood?

One small trial found less eczema dryness and itch with hemp seed oil, one found gut bacteria changes with perilla oil in athletes, and one found fewer high depression scores with perilla oil against a historical control. All are very low certainty.

Q: Can hemp seed oil make me fail a drug test?

Hemp seed oil can carry traces of THC. A review found most studies saw no result above cut-off, but trace levels occurred, and positives came mainly from the product content. Ask a testing body if it matters.

Q: Can they cause allergy?

Seed and tree nut allergies are possible. Perilla seed is a leading cause of seed anaphylaxis in Korean children, chia seed allergy is reported in case reports, and the NHS lists walnuts among common allergic foods. The sources do not say how much allergen the oils carry.

Q: Are they safe with blood thinners?

The Linus Pauling Institute cautions that some seed oils and fish oil may reduce platelet clumping, but it does not name these four oils. Any effect is theoretical. Ask a doctor or pharmacist.

Oils of Salvia hispanica (chia), Cannabis sativa (hemp), Perilla frutescens (perilla) and Juglans regia (walnut) · also called Plant omega-3 oils, ALA oils, chia seed oil, hempseed oil, perilla seed oil, aceite de chia, aceite de nuez, omega-3 vegetal

These four seed and nut oils supply ALA, the plant omega-3 fat, though hemp and walnut oils carry more omega-6 than omega-3. The body turns only part of ALA into the fish-type omega-3s EPA and DHA. Human research is thin: single small trials for blood fats, eczema and gut health, and no trial on heart attacks. Hemp oil can carry traces of THC, and seed or nut allergy and spoiled oil are the main cautions.

General information, not medical advice. Last substantive update October 26, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Chia, Hemp, Perilla and Walnut Oils

Chia, hemp, perilla and walnut oils are pressed from seeds or nuts and give the plant omega-3 fat ALA. They differ a lot in how much ALA they hold. Human trials are few and small, and none shows they replace fish or algae oil.

What these oils are

Chia oil comes from the seeds of Salvia hispanica, hemp seed oil from Cannabis sativa seeds, perilla seed oil from Perilla frutescens seeds and walnut oil from English walnuts (Juglans regia). All four are rich in polyunsaturated fat and turn rancid more easily than olive oil.

The Linus Pauling Institute and NCCIH both describe ALA as a plant omega-3 found in oils and in foods such as chia seeds and walnuts. The NHS lists chia seeds, shelled hemp seeds, walnuts and flaxseed oil among vegan omega-3 foods.

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How the four oils compare

Chia oil is described as up to 60% ALA, and perilla oil as having a high level of ALA (no percentage in the abstract read). Three cold-pressed hemp seed oils from Romania were 9.8 to 14.4% ALA, 49.4 to 51.9% linoleic acid and 16.3 to 22.8% oleic acid. Walnut oil is high in linoleic and alpha-linolenic acids and gives 1.4 g of ALA per tablespoon by the Linus Pauling Institute, against 7.3 g for flaxseed oil.

So hemp and walnut oils give more omega-6 than omega-3. For the whole foods, USDA lists chia seeds at 17.83 g of ALA per 100 g and hulled hemp seed at 8.684 g (with 27.358 g of linoleic acid).

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Can the body turn this ALA into fish-type omega-3?

Only in part. The Linus Pauling Institute quotes about 8% of ALA converted to EPA and 0 to 4% to DHA in young men, and about 21% and 9% in young women. A 2022 opinion article argues that conversion is nutritionally adequate, but accepts that studies differ.

In a trial in pregnancy, chia oil raised red blood cell EPA but not DHA. No trial of hemp, perilla or walnut oil measured it. For direct EPA and DHA see the fish oil and algal oil pages.

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What the research shows

Walnut oil lowered total cholesterol, triglycerides and LDL compared with placebo in a 100-person trial in type 2 diabetes. Chia oil gave larger falls in cholesterol, LDL and triglycerides than soybean oil in 75 women with obesity on a diet. Hemp seed oil improved eczema dryness and itch against olive oil in a small 2005 crossover trial. Perilla oil changed some gut bacteria and constipation scores in 36 athletes.

Each result is a single trial, mostly of blood markers or symptoms, and none has been repeated in the sources read. No trial tested heart attacks, strokes or deaths. Reviews of perilla and walnut oil list many other effects, mostly from lab and animal work.

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Oil versus the whole seed

The oil is the fat part of the seed or nut. It lacks the fibre of chia seeds (34.4 g per 100 g by USDA) and the protein of hemp seeds (31.56 g per 100 g). Most trials here used the oil on its own, so the results do not map onto eating the seeds.

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At a glance

Traditional uses history, not proof

Perilla oil is described as a traditional Japanese seed oil (Kawamura 2023)
Chia is described as native to some Latin American countries (Valenzuela 2015)

Studied for research

ALA supply and food sources, high certainty
Conversion to EPA and DHA, mixed certainty
Blood fats (walnut and chia oil), low certainty
Eczema (hemp), gut health and mood (perilla), breast milk fats (chia), blood sugar (walnut), very low certainty
Heart attacks and deaths, insufficient evidence

Main compounds

Alpha-linolenic acid (ALA)
Linoleic acid (omega-6)
Gamma-linolenic acid (in hemp oil)
Delta-9-THC traces (hemp oil)

Common forms

Cold-pressed bottled oils
Softgel capsules (for example perilla)
The whole seeds and walnuts (separate pages)

Research links: Perilla seed oil review (Li 2024) · Walnut oil and blood fats in type 2 diabetes (2017 trial) · Hemp seed oil and eczema (2005 trial) · THC in hemp seed oils (2024 study) · NCCIH: Omega-3 supplements · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Plant omega-3 oils: seed or nut oils from chia (Salvia hispanica), hemp (Cannabis sativa), perilla (Perilla frutescens) and English walnut (Juglans regia)
Synonyms: Plant omega-3 oils; ALA oils; Chia seed oil; Hempseed oil; Perilla seed oil; Walnut oil
Common names: Chia oil (English); Hemp seed oil (English); Hempseed oil (English); Perilla oil (English); Perilla seed oil (English); Walnut oil (English); Aceite de chia (Spanish); Aceite de semilla de canamo (Spanish); Aceite de perilla (Spanish); Aceite de nuez (Spanish)
Family or group: Omega fatty acids (plant sources). Flaxseed oil and algal oil have their own pages.
Classification: Plantae > Lamiales (chia, perilla); Rosales (hemp); Fagales (walnut) > Lamiaceae (chia, perilla); Cannabaceae (hemp); Juglandaceae (walnut) > Salvia; Cannabis; Perilla; Juglans > Salvia hispanica L.; Cannabis sativa L.; Perilla frutescens (L.) Britton; Juglans regia L.
Native range: Chia is described as native to some Latin American countries (Valenzuela 2015). The others were not researched for this page.
What it looks like: Fruit: The oils are pressed from seeds (chia, hemp, perilla) or nut kernels (walnut).
Harvest and processing: A 2026 review says walnut oil composition and oxidation state vary with raw material, extraction, storage and processing; a 2025 study tested cold-pressed hemp seed oils. Perilla oil is prone to oxidation (2024 review).
Look-alikes and adulterants: Name: Flaxseed oil; Note: The richest common plant ALA oil, with its own page.; Name: CBD oil; Note: A different product from the cannabis plant; a 2026 review describes hemp oil as derived from hemp seeds. Reviews group them when discussing THC and drug tests.; Name: The whole seeds and nuts; Note: Chia seeds, hemp seeds, perilla seeds and walnuts add fibre and protein that the oils lack, and have their own pages.; Name: Perilla leaf (shiso); Note: A different plant part; this page is about the seed oil.
Sustainability and conservation: Not assessed.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
		Kawamura 2023 (abstract)
		Valenzuela 2015 (abstract)
		Kacargil 2026 (abstract)

Traditional use shows how it was used. It does not show that it works or is safe today.

What is inside, and how it may work

What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Alpha-linolenic acid (ALA) PubChem 5280934	omega-3 polyunsaturated fatty acid, 18 carbons	Seed or nut oil Chia oil up to 60%; hemp seed oil 9.8 to 14.4% (three Romanian varieties); perilla oil described as high; walnut oil 1.4 g per tablespoon (Linus Pauling Institute)	Essential fat; starting material for EPA and DPA in the body (limited). ^{15 3 4 19}	Human data
Linoleic acid (LA) PubChem 5280450	omega-6 polyunsaturated fatty acid	Seed or nut oil Hemp seed oil 49.4 to 51.9% (three Romanian varieties); walnut oil high (review); hulled hemp seed 27.358 g per 100 g (USDA)	Essential omega-6 fat; its role was not examined further in the sources read. ^{3 14 24}	Human data
Gamma-linolenic acid (GLA) PubChem 5280933	omega-6 polyunsaturated fatty acid	Hemp seed oil Present in hemp seed oil; no percentage in the abstracts read	Blood GLA rose after hemp seed oil in one eczema trial. ^{2 3}	Human data
Tocopherols (vitamin E forms), phytosterols, phenolics	minor fat-soluble components	Seed or nut oil Walnut oil: 0.4 mg alpha-tocopherol per 100 g (USDA); hemp seed oil phenolics 118 to 160 mg GAE per kg	Antioxidant components; a review says they vary with processing. ^{24 3 14}	Lab
Delta-9-THC and other cannabinoids (hemp seed oil)	cannabinoids	Residue from the plant on the seeds 0.2 to 6.7 mg per kg in 30 commercial oils; 0.11 to 31.08 micrograms per mL in 20 others	THC is the psychoactive cannabinoid; seed oil should contain very little. ^{10 7}	Human relevant contaminant

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Conversion of ALA to EPA, DPA and DHA	Not specified in the sources read	Conversion exists but is limited (nutrition summary), and an expert opinion argues it is nutritionally adequate. In pregnancy, chia oil raised red blood cell EPA but not DHA. ^{19 1 15}	Human data
Effects on blood fats	Not established	Two trials report lower cholesterol and triglycerides; no mechanism was established in the abstracts read. ^{17 11}	Human data
Gut bacteria	Not specified	Perilla oil changed some bacteria groups in athletes; a 2024 review lists gut bacteria effects, mostly from lab work. ^{8 9}	Human (small)
Antioxidant, anti-inflammatory and other cell effects	Not specified	Reviews of perilla and walnut oil list these effects from lab and animal work. Not shown in people. ^{4 9 14}	Lab and animal

Absorption, metabolism and elimination

Absorption: Not described in the sources read.
Distribution: Not described in the sources read.
Metabolism: ALA is partly converted to EPA and a little DHA. The Linus Pauling Institute quotes about 8% to EPA in young men and about 21% in young women, with 0 to 4% and about 9% to DHA.
Elimination: Not described in the sources read.
Bioavailability: A 2024 review says perilla oil's oxidation lowers its nutritional value and bioavailability, and that encapsulation is being studied.

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Isolated compounds versus whole extracts

The oils are the fat part of the seed or nut. They give ALA but not the fibre and protein of chia seeds (34.4 g fibre per 100 g by USDA), hulled hemp seed (31.56 g protein per 100 g) or walnuts. Most trials here used the oil by itself, so results do not map onto eating the seeds.

Nutritional composition

Seed values are from USDA FoodData Central SR Legacy (April 2018), read from a saved local copy: chia seeds ALA 17.83 g and linoleic acid 5.835 g per 100 g; hulled hemp seed ALA 8.684 g and linoleic acid 27.358 g per 100 g; walnut oil 9.1 g saturated, 22.8 g monounsaturated and 63.3 g polyunsaturated fat per 100 g. The ALA per tablespoon of walnut oil (1.4 g) is from the Linus Pauling Institute table. USDA has no perilla record in the saved set.

10benefits and uses looked at

24studies and sources checked

High certaintybest evidence rating found

6lab markers tracked in trials

1 high certainty1 mixed findings1 low certainty5 very low certainty2 not enough evidence

What was looked at

The 10 benefits and uses checked for Chia, Hemp, Perilla and Walnut Oils, each with how strong the evidence is. Tap one to open it.

How much plant omega-3 (ALA) each oil suppliesHigh certainty
Turning ALA into fish-type omega-3 (EPA and DHA)Mixed findings
Blood fats: cholesterol and triglyceridesLow certainty
Heart attacks, strokes and deathsNot enough evidence
Eczema (atopic dermatitis) with hemp seed oilVery low certainty
Gut bacteria and constipation with perilla oilVery low certainty
Mood after childbirth with perilla oilVery low certainty
Breast milk fats after chia oil in pregnancyVery low certainty
Blood sugar in type 2 diabetes with walnut oilVery low certainty
Inflammation, brain, weight and other effectsNot enough evidence

Lab markers tracked in the studies

Blood EPA and DHA levelsLDL cholesterolTriglyceridesHbA1c and fasting blood sugarSkin dryness, itch and medicine useGut bacteria and constipation score

What is Chia, Hemp, Perilla and Walnut Oils good for?

The main studied uses and how strong the human evidence is for each. Most results come from one small trial per oil.

How much plant omega-3 (ALA) each oil suppliesHigh certaintyChia oil is described as up to 60% ALA, and perilla oil as high in ALA. Cold-pressed hemp seed oil was 9.8 to 14.4% ALA and about half linoleic acid (omega-6). Walnut oil gives 1.4 g of ALA per tablespoon by the Linus Pauling Institute, compared with 7.3 g for flaxseed oil. Turning ALA into fish-type omega-3 (EPA and DHA)Mixed findingsThe body turns only part of ALA into EPA and little into DHA, and experts disagree on whether that is enough. No trial of these oils tested it as a swap for fish or algae oil. Blood fats: cholesterol and triglyceridesLow certaintyOne trial of walnut oil in 100 people with type 2 diabetes and high blood fats, and one of chia oil in 75 women with obesity, found lower cholesterol, LDL and triglycerides. Each is a single trial of blood markers. Heart attacks, strokes and deathsNot enough evidenceNo trial of chia, hemp, perilla or walnut oil on heart attacks, strokes or deaths was found. Eczema (atopic dermatitis) with hemp seed oilVery low certaintyA 20-week crossover trial found less dryness and itch and less use of skin medicines with hemp seed oil than with olive oil. It is one small trial from 2005. Gut bacteria and constipation with perilla oilVery low certaintyIn 36 female athletes, higher perilla oil intake changed some gut bacteria and improved a constipation score over 8 weeks. Mood after childbirth with perilla oilVery low certaintyA smaller share of women on perilla oil had high depression scores than in an earlier comparison group, but that group was not concurrent and two authors have oil-company links. Breast milk fats after chia oil in pregnancyVery low certaintyIn 40 women, chia oil raised ALA in milk and briefly raised milk DHA, but not red blood cell DHA. Blood sugar in type 2 diabetes with walnut oilVery low certaintyOne open trial with no placebo found lower HbA1c and fasting blood sugar with walnut oil in type 2 diabetes. Inflammation, brain, weight and other effectsNot enough evidenceReviews list antioxidant, anti-inflammatory, brain and other effects, mostly from lab and animal work; human trials are still needed.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

How much plant omega-3 (ALA) each oil supplies

High certainty

All four oils carry ALA, the plant omega-3 fat, but in very different amounts. Chia oil and perilla oil are rich in it. Hemp and walnut oils have more of the omega-6 fat linoleic acid than ALA.

6 studiesCold-pressed liquid oils and capsules; forms are not compared here.

Studies, doses and limits

What the trials found

A trial paper describes chia oil as up to 60% ALA. A review describes perilla seed oil as having a high level of ALA (no percentage in the abstract). Cold-pressed hemp seed oils from three Romanian varieties were 9.8 to 14.4% ALA and about 50% linoleic acid. A review says walnut oil has high proportions of both linoleic and alpha-linolenic acids. The Linus Pauling Institute lists walnut oil at 1.4 g of ALA per tablespoon, compared with 7.3 g for flaxseed oil. For the whole foods, USDA lists chia seeds at 17.83 g of ALA per 100 g and hulled hemp seed at 8.684 g (with 27.358 g of linoleic acid).

Results

Chia and perilla oils are the richest ALA sources of the four. Hemp and walnut oils give much less ALA and more omega-6. Per-spoon figures for chia, hemp and perilla oil were not found, so a spoon-for-spoon comparison with flaxseed oil is only possible for walnut oil.

Effect sizes as reported

Hemp seed oil: omega-6 to omega-3 ratio 3.93 to 5.53 (Romanian cold-pressed samples). Percentages vary with variety, pressing and storage.

Why this rating

High that the fats are present as described. The exact percentages differ between samples and sources.

Form and dose studied

Cold-pressed liquid oils and capsules; forms are not compared here.

Who was studied

General population.

Limits

Perilla oil has no percentage in the abstract. Figures come from different sources (lab analyses, a trial abstract, USDA seed data, one nutrition table), so they are not strictly like-for-like.

Why researchers looked

People pick these oils as vegan or plant sources of omega-3, so the first question is how much ALA each really holds.

Traditional use

Perilla oil is a traditional Japanese seed oil (Kawamura 2023). Chia is a plant native to some Latin American countries (Valenzuela 2015). No source read describes a long traditional medicine use for the four oils as supplements.

Proposed mechanism Established nutrition

ALA is an essential fat the body cannot make, so it has to come from food. Seeds and nuts store it in their oil.

A proposed mechanism does not show that the effect happens in people.

See the Safety tab. Oils turn rancid easily.

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Turning ALA into fish-type omega-3 (EPA and DHA)

Mixed findings

The body can turn some ALA into EPA and a little DHA. Experts disagree on whether that is enough. These four oils have not been tested as a swap for fish or algae oil.

3 studiesDietary ALA from food and oils.

Studies, doses and limits

What the trials found

The Linus Pauling Institute quotes about 8% of ALA converted to EPA and 0 to 4% to DHA in young men, and about 21% and 9% in young women, and says the low conversion is why EPA and DHA should be obtained from food or supplements. A 2022 opinion article argues conversion is nutritionally adequate, noting that vegetarians who eat no EPA or DHA show no reported harm, while accepting that studies differ and cannot give a firm consensus.

Results

Conversion is real but limited, and experts disagree about whether it is enough. No trial read measured this for hemp, perilla or walnut oil. In the chia oil trial in pregnancy, red blood cell EPA rose but DHA did not change.

Effect sizes as reported

Conversion figures are from one nutrition summary; no pooled effect size applies.

Why this rating

Mixed: a nutrition summary says conversion is low, while an expert opinion argues it is adequate. Neither is a trial of these oils.

Form and dose studied

Dietary ALA from food and oils.

Who was studied

Healthy young adults (conversion figures); vegetarians (opinion article).

Limits

The conversion figures are decades old and come from small tracer studies. The opinion article argues one side. The NIH Office of Dietary Supplements fact sheet was blocked and not read.

Why researchers looked

Fish and algae oils give EPA and DHA directly. People who avoid fish ask whether plant oils can do the same job.

Traditional use

Proposed mechanism Human physiology

ALA is the starting material for longer omega-3 fats such as EPA and DHA, made through a series of steps in the body.

A proposed mechanism does not show that the effect happens in people.

None specific.

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Blood fats: cholesterol and triglycerides

Low certainty

One trial of walnut oil in people with type 2 diabetes, and one of chia oil in women with obesity, found lower cholesterol and triglycerides. Each is a single trial, so the evidence is thin.

3 studiesWalnut oil (Persian walnut) and chia seed oil; amounts used are in th…

Studies, doses and limits

What the trials found

In a 100-person placebo-controlled trial, people with type 2 diabetes and high blood fats had lower total cholesterol, triglycerides and LDL after 90 days of Persian walnut oil than on placebo. In a 75-woman trial on a reduced-calorie diet, the chia oil group had larger falls in cholesterol, LDL and triglycerides, and a rise in HDL, than the soybean oil placebo group after 8 weeks. No human trial of hemp or perilla oil on blood fats was read.

Results

Possible improvements in blood fats with walnut oil (in diabetes) and chia oil (in obesity). Neither result has been repeated in the sources read.

Effect sizes as reported

Walnut oil vs placebo: total cholesterol -30.04, triglycerides -15.04, LDL -30.44 (all treatment differences, units not given). Chia oil group: cholesterol -45.36, LDL -42.53, triglycerides -49.74, HDL +3.73.

Why this rating

Low: two single trials from different groups, a blood-marker outcome, and no replication.

Form and dose studied

Walnut oil (Persian walnut) and chia seed oil; amounts used are in the studies table only.

Who was studied

People with type 2 diabetes and high blood fats (walnut oil); women with obesity on a diet (chia oil).

Limits

Results are for those groups only. Both are lab markers, not heart attacks or strokes. Units were not given in the abstracts.

Why researchers looked

ALA-rich oils are often promoted for heart health, and blood fats are the easiest thing to measure.

Traditional use

Proposed mechanism Preliminary mechanism

The mechanism was not established in the abstracts read. A 2024 review of perilla oil lists lipid-lowering effects, mostly from lab work.

A proposed mechanism does not show that the effect happens in people.

None reported in the abstracts.

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Heart attacks, strokes and deaths

Not enough evidence

No trial read tested chia, hemp, perilla or walnut oil on heart attacks, strokes or deaths, so nothing can be said about these outcomes for the oils.

2 studiesNot applicable.

Studies, doses and limits

What the trials found

A search of PubMed found no outcome trial of these four oils for heart events. The general question of ALA and the heart is covered on the flaxseed oil and plant omega-3 page.

Results

Insufficient evidence for the four oils.

Why this rating

No trials of these oils on heart events were found.

Limits

The search was a targeted PubMed search, not a full systematic review.

Why researchers looked

Heart disease is the main reason plant omega-3 is promoted.

Traditional use

Proposed mechanism Not established

Not applicable.

A proposed mechanism does not show that the effect happens in people.

Do not use an oil to treat heart symptoms; see the Safety tab for urgent signs.

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Eczema (atopic dermatitis) with hemp seed oil

Very low certainty

One small 2005 trial found that eczema symptoms and use of skin medicines improved on hemp seed oil compared with olive oil. It has not been repeated in the sources read.

1 studiesHemp seed oil taken by mouth; the amount used is in the studies table…

Studies, doses and limits

What the trials found

In a 20-week crossover trial, blood linoleic acid, ALA and GLA rose after hemp seed oil, and dryness and itch scores improved (P=0.027) and use of skin medicines fell (P=0.024) compared with olive oil. Skin water loss fell but not by a margin that passes the usual 0.05 cut-off (P=0.074).

Results

Possible improvement in dryness, itch and medicine use in eczema.

Effect sizes as reported

Dryness and itch P=0.027; medicine use P=0.024; water loss P=0.074.

Why this rating

Very low: one small trial from 2005, single-blind, symptoms from a questionnaire, no replication found.

Form and dose studied

Hemp seed oil taken by mouth; the amount used is in the studies table only.

Who was studied

People with atopic dermatitis in Finland.

Limits

Sample size was not in the abstract. The comparison oil was olive oil, so it shows hemp oil against another oil, not against nothing.

Why researchers looked

Hemp seed oil has both omega-6 and omega-3 fats, and an old trial reported benefits for eczema.

Traditional use

Proposed mechanism Preliminary mechanism

The trial authors suggest the benefit came from the balanced supply of polyunsaturated fats. This is their idea, not a proven mechanism.

A proposed mechanism does not show that the effect happens in people.

Hemp seed oil can carry THC traces; see Safety.

Gut bacteria and constipation with perilla oil

Very low certainty

A trial in 36 female athletes found changes in gut bacteria and less constipation with the higher perilla oil intake. These are small changes in markers.

2 studiesPerilla oil mixed into a jelly; amounts are in the studies table only.

Studies, doses and limits

What the trials found

After 8 weeks, the higher-intake group had fewer Proteobacteria (P=0.036), more butyrate-producing Lachnospiraceae (P=0.007), lower urinary indoxyl sulphate (P=0.010) and a larger fall in constipation score than placebo (P=0.035 between groups).

Results

Small changes in gut bacteria and in constipation score in athletes.

Effect sizes as reported

Proteobacteria P=0.036; Lachnospiraceae P=0.007; indoxyl sulphate P=0.010; constipation P=0.035.

Why this rating

Very low: one small trial in one group of athletes, and bacteria counts are not illness outcomes.

Form and dose studied

Perilla oil mixed into a jelly; amounts are in the studies table only.

Who was studied

Female athletes in Japan.

Limits

Small, short, athletes only. Only the abstract was read.

Why researchers looked

Perilla oil is a traditional Japanese seed oil, and omega-3 fats may influence gut bacteria.

Traditional use

Proposed mechanism Preliminary mechanism

The authors say omega-3 intake may shift gut bacteria. A review lists effects on gut bacteria, mostly from lab work.

A proposed mechanism does not show that the effect happens in people.

None reported in the abstract.

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Mood after childbirth with perilla oil

Very low certainty

A small Japanese study found fewer high depression scores after birth in women who took perilla oil than in an earlier comparison group. The comparison was not randomised, so the result is weak.

1 studiesPerilla oil (ALA) or fish oil.

Studies, doses and limits

What the trials found

Women took perilla oil or fish oil for 12 weeks from mid-pregnancy. The share with a high Edinburgh depression score was 12.0% in the perilla group (P=0.044 against a historical control of 21.6%) and 22.3% in the fish oil group (P=0.882). The two groups tended to differ (P=0.059). Bonding scores did not change.

Results

A possible lower rate of high depression scores with perilla oil, not confirmed.

Effect sizes as reported

Perilla 12.0% vs fish oil 22.3% vs historical control 21.6% (high score).

Why this rating

Very low: the comparison group was from an earlier study, the sample size was not in the abstract, and two authors are linked to oil companies.

Form and dose studied

Perilla oil (ALA) or fish oil.

Who was studied

Healthy first-time mothers in Japan.

Limits

Not a concurrent placebo comparison. The effect on actual postpartum depression diagnosis was not tested.

Why researchers looked

Omega-3 fats have been studied for mood around pregnancy, and perilla oil is an ALA source.

Traditional use

Proposed mechanism Not established

The authors suggest ALA may stabilise mood. This is not established.

A proposed mechanism does not show that the effect happens in people.

Pregnancy: see Safety.

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Breast milk fats after chia oil in pregnancy

Very low certainty

In a small trial, women who took chia oil in late pregnancy and while nursing had more ALA in their milk and a short rise in milk DHA, but not in their blood DHA.

1 studiesChia oil from the third trimester; the amount is in the studies table…

Studies, doses and limits

What the trials found

In 40 women, the chia group had more ALA and EPA in red blood cells and more ALA in milk. DHA in red blood cells did not change and DHA in milk rose only in the first 3 months of nursing.

Results

Changes in milk and blood fat levels; no infant outcomes were measured.

Effect sizes as reported

No numbers in the abstract.

Why this rating

Very low: one small trial, a fat-level outcome, and no placebo oil.

Form and dose studied

Chia oil from the third trimester; the amount is in the studies table only.

Who was studied

Healthy pregnant and nursing women in Chile.

Limits

Fat levels in milk are not the same as better outcomes for the baby.

Why researchers looked

ALA and DHA in milk matter for infant feeding, so researchers tested whether chia oil changes them.

Traditional use

Proposed mechanism Human physiology

ALA from the oil is partly converted to longer omega-3 fats. This trial measured the result.

A proposed mechanism does not show that the effect happens in people.

See Safety for pregnancy and breastfeeding.

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Blood sugar in type 2 diabetes with walnut oil

Very low certainty

One open trial found lower HbA1c and fasting blood sugar with walnut oil. There was no placebo, so the result is weak.

1 studiesWalnut oil; amount in the studies table only.

Studies, doses and limits

What the trials found

In 100 people with type 2 diabetes, HbA1c fell from 7.00 to 6.37 (P=0.005) and fasting blood sugar from 158.37 to 137.91 (P=0.001) in the walnut oil group after 3 months. The control group had no intervention and its changes were not significant. Blood pressure and weight did not differ.

Results

Lower blood sugar markers in one open trial.

Effect sizes as reported

HbA1c -7.86% (P=0.005); fasting glucose -8.24% (P=0.001).

Why this rating

Very low: no placebo or blinding mentioned, one trial, one country.

Form and dose studied

Walnut oil; amount in the studies table only.

Who was studied

Adults with type 2 diabetes in Iran.

Limits

Other diet changes were not described in the abstract. People with diabetes should not change treatment because of an oil.

Why researchers looked

The trial authors say polyunsaturated fats may help prevent type 2 diabetes and improve blood fats.

Traditional use

Proposed mechanism Not established

Not established in the abstract.

A proposed mechanism does not show that the effect happens in people.

Ask the diabetes care team before adding any oil to a plan.

¹⁶

Inflammation, brain, weight and other effects

Not enough evidence

Reviews list many effects of these oils, mostly from lab and animal work. They are not proven in people.

3 studiesNot applicable.

Studies, doses and limits

What the trials found

The 2024 reviews of perilla oil list these effects and say large human trials are still needed. No human trial of these oils on inflammation markers, memory or weight management was read.

Results

Insufficient evidence in people.

Why this rating

Insufficient: lab and animal work only.

Limits

Only abstracts of the reviews were read, so which of the effects they cover were studied in people was not checked.

Why researchers looked

Seed oils have been tested in cells and animals for many conditions.

Traditional use

Proposed mechanism Preliminary mechanism

Reviews mention antioxidant, anti-inflammatory, lipid-lowering, blood sugar, brain and immune effects, plus changes in gut bacteria, mostly from lab work.

A proposed mechanism does not show that the effect happens in people.

Not applicable.

^{9 4 14}

Connections to the rest of health

How Chia, Hemp, Perilla and Walnut Oils connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Evidence status	Context	Studies
Balanced Nutrition	High certainty	How much plant omega-3 (ALA) each oil supplies: All four oils carry ALA, the plant omega-3 fat, but in very different amounts. Chia oil and perilla oil are rich in it. Hemp and walnut oils have more of the omega-6 fat linoleic acid than ALA.	^{15 3 4 14 19 24}
Heart Health	High certainty	How much plant omega-3 (ALA) each oil supplies: All four oils carry ALA, the plant omega-3 fat, but in very different amounts. Chia oil and perilla oil are rich in it. Hemp and walnut oils have more of the omega-6 fat linoleic acid than ALA.	^{15 3 4 14 19 24}
Heart Health	Mixed findings	Turning ALA into fish-type omega-3 (EPA and DHA): The body can turn some ALA into EPA and a little DHA. Experts disagree on whether that is enough. These four oils have not been tested as a swap for fish or algae oil.	^{19 1 15}
Brain Health	Mixed findings	Turning ALA into fish-type omega-3 (EPA and DHA): The body can turn some ALA into EPA and a little DHA. Experts disagree on whether that is enough. These four oils have not been tested as a swap for fish or algae oil.	^{19 1 15}
Heart Health	Low certainty	Blood fats: cholesterol and triglycerides: One trial of walnut oil in people with type 2 diabetes, and one of chia oil in women with obesity, found lower cholesterol and triglycerides. Each is a single trial, so the evidence is thin.	^{17 11 9}
Cholesterol Balance	Low certainty	Blood fats: cholesterol and triglycerides: One trial of walnut oil in people with type 2 diabetes, and one of chia oil in women with obesity, found lower cholesterol and triglycerides. Each is a single trial, so the evidence is thin.	^{17 11 9}
Heart Health	Not enough evidence	Heart attacks, strokes and deaths: No trial read tested chia, hemp, perilla or walnut oil on heart attacks, strokes or deaths, so nothing can be said about these outcomes for the oils.	^{4 14}
Healthy Skin	Very low certainty	Eczema (atopic dermatitis) with hemp seed oil: One small 2005 trial found that eczema symptoms and use of skin medicines improved on hemp seed oil compared with olive oil. It has not been repeated in the sources read.	²
Inflammation Balance	Very low certainty	Eczema (atopic dermatitis) with hemp seed oil: One small 2005 trial found that eczema symptoms and use of skin medicines improved on hemp seed oil compared with olive oil. It has not been repeated in the sources read.	²
Gut Health	Very low certainty	Gut bacteria and constipation with perilla oil: A trial in 36 female athletes found changes in gut bacteria and less constipation with the higher perilla oil intake. These are small changes in markers.	^{8 9}
Digestive Support	Very low certainty	Gut bacteria and constipation with perilla oil: A trial in 36 female athletes found changes in gut bacteria and less constipation with the higher perilla oil intake. These are small changes in markers.	^{8 9}
Mood Balance	Very low certainty	Mood after childbirth with perilla oil: A small Japanese study found fewer high depression scores after birth in women who took perilla oil than in an earlier comparison group. The comparison was not randomised, so the result is weak.	⁵
Womens Wellness	Very low certainty	Mood after childbirth with perilla oil: A small Japanese study found fewer high depression scores after birth in women who took perilla oil than in an earlier comparison group. The comparison was not randomised, so the result is weak. Breast milk fats after chia oil in pregnancy: In a small trial, women who took chia oil in late pregnancy and while nursing had more ALA in their milk and a short rise in milk DHA, but not in their blood DHA.	^{5 15}
Balanced Nutrition	Very low certainty	Breast milk fats after chia oil in pregnancy: In a small trial, women who took chia oil in late pregnancy and while nursing had more ALA in their milk and a short rise in milk DHA, but not in their blood DHA.	¹⁵
Blood Sugar Balance	Very low certainty	Blood sugar in type 2 diabetes with walnut oil: One open trial found lower HbA1c and fasting blood sugar with walnut oil. There was no placebo, so the result is weak.	¹⁶
Metabolic Health	Very low certainty	Blood sugar in type 2 diabetes with walnut oil: One open trial found lower HbA1c and fasting blood sugar with walnut oil. There was no placebo, so the result is weak.	¹⁶
Inflammation Balance	Not enough evidence	Inflammation, brain, weight and other effects: Reviews list many effects of these oils, mostly from lab and animal work. They are not proven in people.	^{9 4 14}
Brain Health	Not enough evidence	Inflammation, brain, weight and other effects: Reviews list many effects of these oils, mostly from lab and animal work. They are not proven in people.	^{9 4 14}

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Nutrition	Biological association	High certainty	Studied for: How much plant omega-3 (ALA) each oil supplies Studied for: Breast milk fats after chia oil in pregnancy	^{15 3 4 14 19 24}
Whole Body	Biological association	High certainty	Studied for: How much plant omega-3 (ALA) each oil supplies Studied for: Turning ALA into fish-type omega-3 (EPA and DHA)	^{15 3 4 14 19 24 1 9}
Cardiovascular System	Biological association	Mixed findings	Studied for: Turning ALA into fish-type omega-3 (EPA and DHA) Studied for: Blood fats: cholesterol and triglycerides	^{19 1 15 17 11 9 4 14}
Heart Circulation	Biological association	Low certainty	Studied for: Blood fats: cholesterol and triglycerides Studied for: Heart attacks, strokes and deaths	^{17 11 9 4 14}
Skin	Biological association	Very low certainty	Studied for: Eczema (atopic dermatitis) with hemp seed oil	²
Integumentary System	Biological association	Very low certainty	Studied for: Eczema (atopic dermatitis) with hemp seed oil	²
Gut Health	Biological association	Very low certainty	Studied for: Gut bacteria and constipation with perilla oil	^{8 9}
Digestive System	Biological association	Very low certainty	Studied for: Gut bacteria and constipation with perilla oil	^{8 9}
Stress Mood	Biological association	Very low certainty	Studied for: Mood after childbirth with perilla oil	⁵
Reproductive System	Biological association	Very low certainty	Studied for: Mood after childbirth with perilla oil Studied for: Breast milk fats after chia oil in pregnancy	^{5 15}
Blood Sugar Support	Biological association	Very low certainty	Studied for: Blood sugar in type 2 diabetes with walnut oil	¹⁶
Endocrine System	Biological association	Very low certainty	Studied for: Blood sugar in type 2 diabetes with walnut oil	¹⁶
Nervous System	Biological association	Not enough evidence	Studied for: Inflammation, brain, weight and other effects	^{9 4 14}

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Seed and tree nut allergy	Adverse effect or risk	Reported reactions (seeds)	Reactions are reported to the seeds and nuts; oil allergen content is unknown. Preparation or compound: Perilla, chia and walnut	^{6 13 21}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Blood EPA and DHA levels	Biological association	Very low certainty	Measured in trials: EPA higher, DHA mostly unchanged. A lab change is not the same as a health benefit.	^{15 19}
LDL cholesterol	Biological association	Low certainty	Measured in trials: lower in two trials. A lab change is not the same as a health benefit.	^{17 11}
Triglycerides	Biological association	Low certainty	Measured in trials: lower in two trials. A lab change is not the same as a health benefit.	^{17 11}
HbA1c and fasting blood sugar	Biological association	Very low certainty	Measured in trials: lower in one open trial. A lab change is not the same as a health benefit.	¹⁶
Skin dryness, itch and medicine use	Biological association	Very low certainty	Measured in trials: improved in one small trial. A lab change is not the same as a health benefit.	²
Gut bacteria and constipation score	Biological association	Very low certainty	Measured in trials: changes in bacteria and constipation in one trial. A lab change is not the same as a health benefit.	⁸

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
EPA and DHA	Preliminary mechanism	Human	ALA is a precursor but converts only in part, mostly to EPA.	^{19 1}
Omega-6 fats	Preliminary mechanism	Human relevant	Hemp and walnut oils are mostly omega-6 linoleic acid.	^{3 14}

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Alpha-linolenic acid (ALA)	Biological association	Human	Essential fat; starting material for EPA and DPA in the body (limited). Preparation or compound: Seed or nut oil	^{15 3 4 19}
Linoleic acid (LA)	Biological association	Human	Essential omega-6 fat; its role was not examined further in the sources read. Preparation or compound: Seed or nut oil	^{3 14 24}
Gamma-linolenic acid (GLA)	Biological association	Human	Blood GLA rose after hemp seed oil in one eczema trial. Preparation or compound: Hemp seed oil	^{2 3}
Tocopherols (vitamin E forms), phytosterols, phenolics	Biological association	Lab	Antioxidant components; a review says they vary with processing. Preparation or compound: Seed or nut oil	^{24 3 14}
Delta-9-THC and other cannabinoids (hemp seed oil)	Biological association	Human relevant contaminant	THC is the psychoactive cannabinoid; seed oil should contain very little. Preparation or compound: Residue from the plant on the seeds	^{10 7}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).

Evidence at a glance: what the research found for 10 outcomes

1High certainty

1Low certainty

5Very low certainty

1Mixed findings

2Not enough evidence

Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.

How much plant omega-3 (ALA) each oil supplies 6 studies High certainty Turning ALA into fish-type omega-3 (EPA and DHA) 3 studies Mixed findings Blood fats: cholesterol and triglycerides 3 studies Low certainty Heart attacks, strokes and deaths 2 studies Not enough evidence Eczema (atopic dermatitis) with hemp seed oil 1 study Very low certainty Gut bacteria and constipation with perilla oil 2 studies Very low certainty Mood after childbirth with perilla oil 1 study Very low certainty Breast milk fats after chia oil in pregnancy 1 study Very low certainty Blood sugar in type 2 diabetes with walnut oil 1 study Very low certainty Inflammation, brain, weight and other effects 3 studies Not enough evidence

The evidence

The research centre for Chia, Hemp, Perilla and Walnut Oils. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing ingredient summary, read the Linus Pauling Institute, NCCIH and NHS pages, checked seed values in a saved copy of USDA data, matched plant names in GBIF, and re-read PubMed abstracts for each study. Only abstracts were read for studies. The NIH Office of Dietary Supplements pages were blocked and are marked unread.

Study library: every study we checked 24

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Burdge 2022 alpha-Linolenic acid interconversion is sufficient as a source of longer chain omega-3 polyunsaturated fatty acids in humans: An opinion. Lipids · PMID 35908848 · DOI	Opinion review	Review of human ALA supplement and tracer studies	Dietary ALA Not specific to any one oil	The author argues the view that conversion is too low is not well supported: study designs differ, findings are inconsistent, and no robust agreement is possible. He argues that conversion is nutritionally adequate, since vegetarians who eat no EPA or DHA show no reported harm. No numbers in the abstract (Not applicable) Methods, limits and funding Outcomes: How well ALA is turned into EPA and DHA Limitations: An opinion article, not a systematic review. It argues one side of a debate. Read from the abstract only. Funding and conflicts: Funding not stated in the abstract. Read: abstract
Callaway 2005 Efficacy of dietary hempseed oil in patients with atopic dermatitis. J Dermatolog Treat · PMID 16019622 · DOI	Randomised controlled trial	People with atopic dermatitis (eczema), Finland	Hempseed oil Hemp seed oil (Cannabis sativa) 20 weeks (crossover) · vs Olive oil	After hemp seed oil, blood linoleic acid, ALA and GLA rose, skin dryness and itch scores improved and use of skin medicines fell, compared with olive oil. Dryness and itch P=0.027; skin medicine use P=0.024; water loss through skin P=0.074 (not significant at 0.05). (Not given in the abstract) Methods, limits and funding Outcomes: Blood fatty acids, skin water loss, questionnaire on dryness, itch and medicine use Limitations: Single-blind (as the abstract states), small, symptoms from a questionnaire, one trial from 2005 with no replication found. The sample size was not in the abstract. Funding and conflicts: Funding not stated in the abstract (PubMed lists non-US government research support). Registration: Not stated in the abstract Read: abstract
Floares Oarga 2025 Chemical Profile, Bioactive Constituents and In Vitro Growth Stimulation Properties of Cold-Pressed Hemp Seed Oils from Romanian Varieties: In Vitro and In Silico Evaluation. Plants (Basel) · PMID 41304617 · DOI	Laboratory analysis lab	3 Cold-pressed hemp seed oils from three Romanian varieties (products, not people)	Cold-pressed hemp seed oil Hemp seed oil (Cannabis sativa)	Oils were mostly linoleic acid (49.4 to 51.9%), oleic acid (16.3 to 22.8%) and alpha-linolenic acid (9.8 to 14.4%), with omega-6 to omega-3 ratios of 3.93 to 5.53. Gamma-linolenic acid was also present. In the lab dish, one oil encouraged growth of one probiotic strain. Linoleic 49.4-51.9%; oleic 16.3-22.8%; ALA 9.8-14.4%; omega-6:omega-3 3.93-5.53 (Not applicable) Methods, limits and funding Outcomes: Fatty acid profile, phenolics, carotenoids, and growth of probiotic bacteria in a dish Limitations: Three varieties from one country; the bacteria work is a lab dish test only. Funding and conflicts: Authors declare no conflicts of interest. Read: abstract
Guan 2024 Perilla Seed Oil and Protein: Composition, Health Benefits, and Potential Applications in Functional Foods. Molecules · PMID 39598647 · DOI	Narrative review mixed	Review of composition and reported health effects (mostly lab and food-science work)	Perilla seed oil and protein Perilla seed oil (Perilla frutescens)	The review says perilla seed oil has a high level of ALA, a favourable ratio of unsaturated to saturated fat, and tocopherols and phytosterols, and reports antioxidant, anti-inflammatory and cardiovascular protective effects. It discusses challenges and future research. No numbers in the abstract (Not applicable) Methods, limits and funding Outcomes: Composition, antioxidant, anti-inflammatory and heart-related effects Limitations: A narrative review read from the abstract only. It does not rate how strong the human evidence is. Funding and conflicts: Authors declare no conflicts of interest. Read: abstract
Harauma 2023 Effects of Varied Omega-3 Fatty Acid Supplementation on Postpartum Mental Health and the Association between Prenatal Erythrocyte Omega-3 Fatty Acid Levels and Postpartum Mental Health. Nutrients · PMID 37892462 · DOI	Randomised controlled trial	Healthy first-time mothers from mid-pregnancy, Japan	Perilla oil (ALA) or fish oil (EPA+DHA) Perilla seed oil (Perilla frutescens) About 2.0 g a day of omega-3 (ALA 2.4 g in the perilla group; EPA+DHA 1.7 g in the fish oil group), as stated in the abstract 12 weeks from mid-pregnancy · vs Historical control from an earlier observational study	A smaller share of the perilla oil group had a high depression score than the historical control. The fish oil group did not differ from the control, and the two groups only tended to differ from each other. High EPDS (9 or more): perilla 12.0% (P=0.044 vs control); fish oil 22.3% (P=0.882); historical control 21.6%; perilla vs fish oil P=0.059. Bonding scores: no marked effect. (Not given in the abstract) Methods, limits and funding Outcomes: Edinburgh Postnatal Depression Scale (EPDS), mother-to-infant bonding, blood and milk fatty acids Limitations: The control group was not randomised or concurrent, so the result is weak. The sample size was not in the abstract. The authors say the finding only suggests ALA may help. Funding and conflicts: Two authors belong to an endowed course funded by Ota Oil Co., Ltd. and Nissui Corporation (companies in the oil and food business); the abstract says the funders had no role in the study. Registration: Not stated in the abstract Read: abstract
Jeong 2026 Advancing allergen characterization in Perilla seed: an oil body purification approach. Allergy Asthma Clin Immunol · PMID 41618458 · DOI	Laboratory study human-samples	Serum from children allergic to perilla seed, Korea	Perilla seed oil-body proteins Perilla seed (Perilla frutescens)	The abstract calls perilla seed a leading cause of seed-induced anaphylaxis in Korean children and finds that oleosin proteins (about 14 to 15 kDa) are the main allergen. It does not test the refined oil. IgE binding at 12, 14-15, 20, 33 and 50 kDa (Not applicable) Methods, limits and funding Outcomes: Which seed proteins allergic children react to Limitations: A lab test on seed proteins using children's blood samples. It does not say how much allergen is in pressed or refined oil. Funding and conflicts: Authors declare no competing interests. Read: abstract
Kacargil 2026 Determination of cannabinoids in commercial hemp seeds and hemp seed oil products in Turkiye by LC-MS/MS. Forensic Sci Int · PMID 41621128 · DOI	Laboratory analysis n/a	32 12 hemp seed and 20 hemp seed oil products bought in Turkey (products, not people)	Hemp seed oil and seeds Hemp seed oil (Cannabis sativa)	All samples except one oil had detectable THC. Hemp seed oils had delta-9-THC from 0.11 to 31.08 micrograms per mL (mean 6.64), and the mean total THC in oils was above several national limits quoted in the abstract. Oils: delta-9-THC mean 6.64 ug/mL (0.11 to 31.08); mean total THC 10.21 ug/mL; seeds: delta-9-THC mean 0.78 ug/g (Not applicable) Methods, limits and funding Outcomes: THC, delta-8-THC, CBD, CBN and THCA content Limitations: Products from one country. Limits are quoted as the authors give them and not checked at the source. Turkey applies a zero-tolerance rule, which is why the authors raise legal risk. Funding and conflicts: Authors declare no competing interests. Read: abstract
Kawamura 2023 Effect of 8-week intake of the n-3 fatty acid-rich perilla oil on the gut function and as a fuel source for female athletes: a randomised trial. Br J Nutr · PMID 35705194 · DOI	Randomised controlled trial	36 Female athletes training six times a week, Japan	Perilla oil in a jelly Perilla seed oil (Perilla frutescens) 9 g a day, 3 g a day, or placebo jelly (as stated in the abstract) 8 weeks · vs Placebo jelly	In the higher-intake group, harmful-type gut bacteria (Proteobacteria) fell and butyrate-producing bacteria (Lachnospiraceae) rose, urinary indoxyl sulphate fell and constipation scores improved compared with placebo. Proteobacteria P=0.036; Lachnospiraceae P=0.007; indoxyl sulphate P=0.010; constipation score between groups P=0.035. (Not given in the abstract) Methods, limits and funding Outcomes: Gut bacteria, constipation score, urinary indoxyl sulphate Limitations: 36 athletes in three groups, one sport population, short, and a gut microbiota change is not a clinical outcome. Only the abstract was read. Funding and conflicts: Funding not stated in the abstract. Registration: Not stated in the abstract Read: abstract
Li 2024 Perilla Seed Oil: A Review of Health Effects, Encapsulation Strategies and Applications in Food. Foods · PMID 39594031 · DOI	Narrative review mixed	Review of health effects of perilla seed oil, mostly lab work	Perilla seed oil Perilla seed oil (Perilla frutescens)	The review lists these effects, says the oil is prone to oxidation, and says the mechanisms still need to be explained and the benefits confirmed in large human trials. No numbers in the abstract (Not applicable) Methods, limits and funding Outcomes: Antioxidant, anti-inflammatory, lipid-lowering, blood sugar, brain, immune and gut bacteria effects Limitations: A narrative review read from the abstract only; the abstract itself calls for large human trials. Funding and conflicts: Authors declare no competing interests. Read: abstract
Lindekamp 2024 Quantification of sixteen cannabinoids in hemp seed edible oils and the influence of thermal processing on cannabinoid contents and profiles. Food Addit Contam Part A · PMID 38588664 · DOI	Laboratory analysis n/a	30 30 commercial hemp seed edible oils (products, not people)	Hemp seed edible oil Hemp seed oil (Cannabis sativa) Heating test: up to 200 C for up to 60 minutes	Total cannabinoids ranged from 9 to 279 mg per kg. Delta-9-THC ranged from 0.2 to 6.7 mg per kg. Three samples were above the EU maximum of 7.5 mg per kg (as the abstract states it) for hemp seed oils. Heavy heating cut total cannabinoids by 38% and raised delta-9-THC by 22%. Delta-9-THC 0.2 to 6.7 mg/kg; 3 of 30 samples over the EU limit; heating: -38% total, +22% delta-9-THC (Not applicable) Methods, limits and funding Outcomes: Cannabinoid content including delta-9-THC Limitations: Product testing from one market and time, not human data. The abstract does not say which country the oils came from. Funding and conflicts: Funding not stated in the abstract. Read: abstract
Oliveira-de-Lira 2018 Supplementation-Dependent Effects of Vegetable Oils with Varying Fatty Acid Compositions on Anthropometric and Biochemical Parameters in Obese Women. Nutrients · PMID 30037019 · DOI	Randomised controlled trial	75 Women with obesity (BMI 30 to 39.9) on a reduced-calorie diet, Brazil	Chia oil (one of four arms: coconut, safflower, chia, soybean placebo) Chia seed oil (Salvia hispanica) 8 weeks · vs Soybean oil (placebo)	The chia oil group had larger falls in total cholesterol, LDL and triglycerides and a rise in HDL, while coconut oil had the larger effect on belly fat and blood sugar. Each oil gave a different pattern. Chia group change: cholesterol -45.36 +/- 0.94; LDL -42.53 +/- 22.65; triglycerides -49.74 +/- 26.3; HDL +3.73 +/- 1.24 (P=0.007). Units not given in the abstract. (Not given in the abstract) Methods, limits and funding Outcomes: Weight, body fat, blood fats, blood sugar and HbA1c Limitations: About 19 women per group, 8 weeks, everyone on a diet that causes weight loss. The comparison oil (soybean) also has fats, so this is oil versus oil, not oil versus nothing. Not clear from the abstract that the chia group differed from placebo in a formal test for each marker. Funding and conflicts: Authors declare no conflict of interest. Registration: Not stated in the abstract Read: abstract
Ovat 2026 Impact of CBD and hemp oil use on drug test results: a systematic review. Int J Legal Med · PMID 41942676 · DOI	Systematic review	Review of 12 studies on CBD oil and hemp oil use and drug tests	CBD oil and hemp oil Hemp seed oil (Cannabis sativa), and CBD oil Studies from March 2014 to March 2024	Five of eight studies found these oils did not produce results above cut-off levels, but trace levels near detection limits were found. Positive results mainly arise from the product itself (undeclared or too much THC, mislabelling, contamination). Oversight of labelling is uneven. 12 of 477 results met the criteria; 5 of 8 studies found no result above cut-off (Not applicable) Methods, limits and funding Outcomes: Whether use of these oils leads to a positive THC drug test Limitations: Few studies, mixed designs, and the review covers CBD oil as well as hemp seed oil. Only the abstract was read. Funding and conflicts: Not stated in the abstract. Read: abstract
Porr 2026 Chia Seed Allergy: Emerging Clinical Evidence, Molecular Allergens, and the Unresolved Question of Cross-Reactivity. Nutrients · PMID 42797010 · DOI	Narrative review	Review of case reports, case series and lab work on chia seed allergy	Chia seed Chia seed (Salvia hispanica)	Clinical evidence is limited to a few case reports and one case series of immediate reactions, skin signs and anaphylaxis. Lab work finds proteins that bind IgE, with cross-reaction to sesame, but that does not prove a real-world allergy. Prevalence and risk cannot be stated. No numbers in the abstract (Not applicable) Methods, limits and funding Outcomes: Allergic reactions to chia seed Limitations: Seed allergy, not oil allergy. The abstract does not discuss chia oil. Funding and conflicts: Authors declare no conflicts of interest. Read: abstract
Shen 2026 Walnut oil from raw material to physiological function: an integrated process-chain perspective on quality, oxidative stability, authentication and health effects. Food Funct · PMID 42861681 · DOI	Narrative review mixed	Review of walnut oil quality and health studies (preclinical and human)	Walnut oil Walnut oil (Juglans regia and Juglans sigillata)	The review says walnut oil has high proportions of linoleic and alpha-linolenic acids and variable tocopherols, phytosterols and phenolics. Composition and oxidation state vary with raw material, processing and storage. Direct human studies mostly look at short-term surrogate endpoints. No numbers in the abstract (Not applicable) Methods, limits and funding Outcomes: Fatty acids, tocopherols, oxidation, and health-related outcomes Limitations: Published online October 2026; read from the abstract only. It separates animal findings from human evidence. Funding and conflicts: Funding not stated in the abstract. Read: abstract
Valenzuela 2015 Modification of Docosahexaenoic Acid Composition of Milk from Nursing Women Who Received Alpha Linolenic Acid from Chia Oil during Gestation and Nursing. Nutrients · PMID 26247968 · DOI	Randomised controlled trial	40 Healthy pregnant women aged 22 to 35, Chile	Chia oil Chia seed oil (Salvia hispanica) 16 mL a day (as stated in the abstract) From the third trimester to 6 months of nursing · vs Normal diet (no oil)	Chia oil raised ALA and EPA in red blood cells and ALA in milk. DHA in red blood cells was not changed, and DHA in milk rose only during the first 3 months of nursing. No numbers in the abstract; 21 controls and 19 in the chia group. (Not given in the abstract) Methods, limits and funding Outcomes: ALA, EPA and DHA in red blood cells and breast milk Limitations: Small, no placebo oil, and it measured fat levels, not baby outcomes. Only the abstract was read. Funding and conflicts: Funding not stated in the abstract. Registration: Not stated in the abstract Read: abstract
Zibaeenezhad 2016 The Effect of Walnut Oil Consumption on Blood Sugar in Patients With Diabetes Mellitus Type 2. Int J Endocrinol Metab · PMID 28115966 · DOI	Randomised controlled trial	100 Adults with type 2 diabetes, Iran	Walnut oil Walnut oil (Juglans regia) 15 g a day (as stated in the abstract) 3 months · vs No intervention (no placebo)	HbA1c and fasting blood sugar fell in the walnut oil group; blood pressure, weight and BMI did not differ between groups. The comparison group got no placebo. HbA1c from 7.00 to 6.37 (mean fall 7.86%, P=0.005); fasting blood sugar from 158.37 to 137.91 (mean fall 8.24%, P=0.001); control group changes not significant. (Not given in the abstract) Methods, limits and funding Outcomes: Blood pressure, fasting blood sugar, HbA1c, weight, BMI Limitations: No placebo and no blinding is mentioned, so expectations and other diet changes could explain part of the result. Small, single-centre, 3 months. Funding and conflicts: Funding not stated in the abstract. Registration: Not stated in the abstract Read: abstract
Zibaeenezhad 2017 Effects of walnut oil on lipid profiles in hyperlipidemic type 2 diabetic patients: a randomized, double-blind, placebo-controlled trial. Nutr Diabetes · PMID 28394361 · DOI	Randomised controlled trial	100 Adults aged 35 to 75 with type 2 diabetes and high blood fats, Iran	Persian walnut oil Walnut oil (Juglans regia) 15 cc a day (as stated in the abstract) 90 days · vs Placebo	Compared with placebo, total cholesterol, triglycerides and LDL were lower and the cholesterol-to-HDL ratio was lower. HDL showed a trend upward that did not reach significance. Treatment difference: total cholesterol -30.04 (P<0.001); triglycerides -15.04 (P=0.021); LDL -30.44 (P<0.001); total/HDL ratio -0.72 (P<0.001); HDL +2.28 (P=0.06). Share reaching LDL below 100: 20% vs 0%. (Not given in the abstract) Methods, limits and funding Outcomes: Total cholesterol, triglycerides, LDL, HDL, cholesterol-to-HDL ratio Limitations: One trial in one country and one disease group. The abstract does not give units, the oil type (cold-pressed or refined), or whether other foods changed. Lab markers are not heart attacks or strokes. Funding and conflicts: Authors declare no conflict of interest. Registration: Not stated in the abstract Read: abstract
s-gbif-taxa GBIF species match (checked 2026-10-26): Salvia hispanica L. (2926992), Cannabis sativa L. (5361880), Perilla frutescens (L.) Britton (5341394), Juglans regia L. (3054368) · Source	Database record n/a			Methods, limits and funding Read: full-text
s-lpi-efa Linus Pauling Institute, Oregon State University: Essential Fatty Acids (page updated May 2019) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-nccih-omega3 NCCIH (US National Institutes of Health): Omega-3 Supplements: What You Need To Know (last updated November 2024) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-nhs-food-allergy NHS: Food allergy (last reviewed 20 August 2026) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-nhs-vegan NHS: The vegan diet (last reviewed 5 June 2026) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-ods-omega3 NIH Office of Dietary Supplements: Omega-3 Fatty Acids fact sheet · Source	Reference database n/a			Methods, limits and funding Read: not-read
s-usda-sr-legacy USDA FoodData Central, SR Legacy (April 2018 release): chia seeds (FDC 170554), hemp seed hulled (FDC 170148), walnut oil (FDC 171030) · Source	Nutrient database n/a			Methods, limits and funding Read: full-text

What we do not know yet

No trial of these oils on heart attacks, strokes or deaths was found.
Each use rests on one small trial, with no repeats found.
The NIH Office of Dietary Supplements fact sheets were blocked, so any official upper limit is not stated.
No source says how much allergen refined or pressed oil carries.
No percentage of ALA for perilla oil, and no per-spoon figures for chia, hemp or perilla oil, were found.
Capsule quality (label accuracy, contaminants) was not surveyed.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue before the page changes.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Metabolic 2

●

LDL cholesterol

Lower in two trials in trials

The cholesterol carried by LDL particles, often called bad cholesterol.

Low certainty

Results and what it means

Why it was measured

A common marker of heart disease risk.

Statistical vs. clinical meaning

A blood-marker change; it does not show fewer heart attacks.

Safety implication

None specific.

Study	Result	People	Product
¹⁷	LDL treatment difference -30.44 versus placebo (P<0.001); 20% reached LDL below 100 versus 0%.	100 adults with type 2 diabetes and high blood fats	Persian walnut oil, 90 days
¹¹	Chia group LDL change -42.53 +/- 22.65 (units not given).	75 women with obesity on a diet	Chia oil, 8 weeks, versus soybean oil

^{17 11}

●

Triglycerides

Lower in two trials in trials

A type of blood fat that rises after eating and in some metabolic conditions.

Low certainty

Results and what it means

Why it was measured

A common marker of heart and metabolic risk.

Statistical vs. clinical meaning

A blood-marker change; it does not show fewer heart attacks.

Safety implication

None specific.

Study	Result	People	Product
¹⁷	Triglycerides treatment difference -15.04 (P=0.021).	100 adults with type 2 diabetes and high blood fats	Persian walnut oil, 90 days
¹¹	Chia group triglyceride change -49.74 +/- 26.3 (units not given).	75 women with obesity on a diet	Chia oil, 8 weeks

^{17 11}

Other 4

●

Blood EPA and DHA levels

EPA higher, DHA mostly unchanged in trials

The amounts of the fish-type omega-3 fats EPA and DHA in blood cells or milk.

Very low certainty

Results and what it means

Why it was measured

To see whether plant ALA raises the fish-type omega-3s.

Statistical vs. clinical meaning

A change in a blood marker; it does not show a health benefit.

Safety implication

None specific.

Study	Result	People	Product
¹⁵	Chia oil raised red blood cell ALA and EPA but not DHA; milk DHA rose only in the first 3 months of nursing.	40 pregnant women	Chia oil from the third trimester

^{15 19}

●

HbA1c and fasting blood sugar

Lower in one open trial in trials

HbA1c shows average blood sugar over about 3 months; fasting glucose is a single morning reading.

Very low certainty

Results and what it means

Why it was measured

To see whether walnut oil changes blood sugar control.

Statistical vs. clinical meaning

A blood-marker change; it does not show fewer complications.

Safety implication

None specific.

Study	Result	People	Product
¹⁶	HbA1c from 7.00 to 6.37 (P=0.005); fasting glucose from 158.37 to 137.91 (P=0.001); control group not significant.	100 adults with type 2 diabetes	Walnut oil, 3 months, versus no intervention

¹⁶

●

Skin dryness, itch and medicine use

Improved in one small trial in trials

Questionnaire scores for skin dryness and itch, and how often skin medicines were used.

Very low certainty

Results and what it means

Why it was measured

To see whether hemp seed oil changes eczema symptoms.

Statistical vs. clinical meaning

Symptom scores are subjective; one trial only.

Safety implication

None specific.

Study	Result	People	Product
²	Dryness and itch improved (P=0.027); dermal medication use fell (P=0.024); skin water loss P=0.074.	People with atopic dermatitis	Hemp seed oil, 20 weeks, versus olive oil

●

Gut bacteria and constipation score

Changes in bacteria and constipation in one trial in trials

Counts of bacteria groups in stool and a constipation questionnaire.

Very low certainty

Results and what it means

Why it was measured

To see whether perilla oil changes the gut.

Statistical vs. clinical meaning

Gut bacteria changes are markers, not illnesses.

Safety implication

None specific.

Study	Result	People	Product
⁸	Proteobacteria fell (P=0.036), Lachnospiraceae rose (P=0.007) and constipation scores improved (P=0.035 between groups) in the higher-intake group.	36 female athletes	Perilla oil in jelly, 8 weeks

⁸

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 3

Hemp seed oil can carry traces of THC. Hemp seed oil comes from a plant that makes THC, and testing has found traces in oils. In 30 hemp seed oils, delta-9-THC ranged from 0.2 to 6.7 mg per kg and 3 were above the EU maximum of 7.5 mg per kg (as the abstract states it). In 20 oils bought in Turkey the mean delta-9-THC was 6.64 micrograms per mL. A review says trace levels were found near detection limits in studies of hemp and CBD oils, and that positive drug tests mainly arise from the product itself (undeclared or excess THC, mislabelling, contamination). This matters for people who are drug tested or live where THC rules are strict. Laboratory product testing and systematic review ^{10 7 12}
Seed and nut allergies: perilla, chia and walnut. Perilla seed is described as a leading cause of seed-induced anaphylaxis in Korean children, and lab work finds oleosin proteins as the main allergen. Chia seed allergy is reported in a few case reports and one case series, with possible cross-reaction to sesame that is not shown to matter in real life. The NHS lists tree nuts such as walnuts among the most common allergic foods. None of the sources read says how much allergen refined or pressed oil carries, so people with a seed or tree nut allergy should ask their allergy team before using these oils. Laboratory study, case reports and authoritative guidance ^{6 13 21}
The oils spoil easily. Oils rich in polyunsaturated fat turn rancid more readily than saturated fats (Linus Pauling Institute). A 2024 review says perilla oil is prone to oxidation, and a 2026 review says the oxidation state of walnut oil varies with processing and storage. Check the label and date, keep the oil cool and closed, and do not use it if it smells sharp or bitter. Authoritative guidance and reviews ^{19 9 14}

Side effects 5

Effect	How often	Severity and recovery	Evidence
Digestive upset (heartburn, nausea, diarrhoea) and fishy or unpleasant taste The NCCIH page is mostly about fish-type omega-3 and does not name hemp or perilla oil.	No frequency found. NCCIH says side effects of omega-3 supplements are usually mild.	Usually mild Not stated in the sources read.	Authoritative guidance (omega 3 supplements as a group, mostly fish type) ²⁰
Allergic reactions, including anaphylaxis These studies are about seeds or nuts, not refined oil.	Not known. For chia seed, prevalence cannot be stated; for perilla seed, one study of Korean children calls it a leading cause of seed anaphylaxis.	Can be severe Not applicable.	Case reports and laboratory studies (seeds); no oil specific data ^{6 13 21}
Unexpected THC on a drug test (hemp seed oil) Risk depends on the product.	Five of eight studies in a review found no result above cut-off; trace levels were seen near detection limits.	Legal or work consequences, not a physical harm Not applicable.	Systematic review and product testing ^{12 10 7}
Extra calories Oils are concentrated fat. In the chia oil trial everyone was also on a reduced-calorie diet.	Walnut oil has 884 kcal per 100 g by USDA data.	Not a side effect as such Not applicable.	Nutrient database ²⁴
No harm was reported in the trial abstracts Abstracts may leave out adverse events; full texts were not read.	The walnut oil, chia oil, hemp oil and perilla oil trials read did not report adverse effects in their abstracts.	Not applicable Not applicable	Trial abstracts (not a safety study) ^{17 11 2 8}

Liver

No liver injury from chia, hemp, perilla or walnut oil was found in the sources read. No search of a liver injury database was run.

How often. No frequency was found.

Monitoring. No agency monitoring advice was found.

This is a safety connection. It is not evidence that Chia, Hemp, Perilla and Walnut Oils supports liver health.

Medicines and supplements 4

With	Why it matters	Importance	Evidence	What to do
Blood thinners (anticoagulants) and antiplatelet drugs prescription	The Linus Pauling Institute says high doses of several plant seed oils (it names black currant, borage, evening primrose and flaxseed oil) and fish oil may reduce platelet clumping and should be used with caution with anticoagulants.	The source does not name chia, hemp, perilla or walnut oil. A similar effect from ALA-rich oils is possible in theory but is not shown for these four.	Authoritative guidance (general class concern; theoretical for these oils) Very low certainty ¹⁹	Tell a doctor or pharmacist before use, especially before surgery or if you bruise or bleed easily.
Phenothiazine medicines (such as chlorpromazine) and GLA-containing oils prescription	The Linus Pauling Institute says gamma-linolenic acid supplements, such as evening primrose and borage oil, may raise seizure risk in people on phenothiazines.	Hemp seed oil contains some gamma-linolenic acid (it rose in blood after hemp oil in the eczema trial), but the source names other oils, not hemp. No report of this problem with hemp oil was read.	Authoritative guidance for other oils; not established for hemp oil Very low certainty ^{19 2}	If you take a phenothiazine, ask a doctor or pharmacist before using hemp oil.
Diabetes medicines and blood pressure medicines prescription	No interaction was described in the sources read. The walnut oil trials were done in people with type 2 diabetes; the abstracts do not detail their other treatment.	Unknown. One trial (no placebo) saw lower blood sugar; changes in blood sugar could matter for people on glucose-lowering medicines.	No data; trial abstracts only Not enough evidence ^{16 17}	Ask the diabetes care team before adding a new oil.
Other omega-3 supplements (fish, krill or algal oil) supplement	Additive intake of omega-3 fats. No harmful interaction was found in the sources read.	Not described.	No data Not enough evidence ²⁰	Tell a pharmacist about all supplements you take.

Who should check first 6

Situation	Advice	Evidence
Allergy to seeds or tree nuts (perilla, chia, sesame, walnut)	These oils may not suit someone with a seed or tree nut allergy. Ask an allergy specialist; the sources read do not say how much allergen the oils carry.	Laboratory studies, case reports and authoritative guidance ^{6 13 21}
Pregnancy	A trial gave women chia oil from the third trimester, and another gave perilla oil from mid-pregnancy, with no adverse effects reported in the abstracts. No official statement on these oils in pregnancy was found. Ask a doctor or midwife before use.	Trial abstracts and no official statement ^{15 5}
Breastfeeding	The chia oil trial continued into nursing and reported no adverse effects in the abstract. No official statement was found. Ask a doctor or midwife.	Single trial abstract ¹⁵
Children	No trial of these oils in children was read, and perilla seed allergy is described in children in Korea. Do not give supplements to children without asking a doctor.	No data; allergy study ⁶
People who are drug tested, or live where THC is illegal	Hemp seed oil can contain traces of THC. The review found drug-test positives came mainly from the product itself. Choose with care and ask the employer or testing body if it matters.	Systematic review and product testing ^{12 10 7}
Kidney or liver disease	No source read gave advice on these oils for kidney or liver disease. Ask a doctor.	No data

Overdose, product quality and regulators

Summary. These are food oils and no serious poisoning from them was found in the sources read. The sources point to allergy, spoiled oil and, for hemp seed oil, THC traces.

Animal. Not reviewed; reviews of these oils are mostly animal and lab work.

Human doses studied. Amounts used in trials appear only in the studies list.

High dose or long term signals. Trials lasted 8 weeks to 6 months of nursing. Long-term safety was not described in the abstracts.

Overdose response. Not described in the sources read.

Genotoxicity. Not researched.

Quality varies. The best evidence is for hemp seed oil, where products differ widely in cannabinoid content, and for all four oils, which oxidise easily.

THC and other cannabinoids in hemp seed oil. 30 commercial hemp seed oils had total cannabinoids from 9 to 279 mg per kg and delta-9-THC from 0.2 to 6.7 mg per kg; 3 exceeded the EU maximum of 7.5 mg per kg. Heating at 200 C for 60 minutes raised delta-9-THC by 22%. A second study of 20 oils found more delta-9-THC (up to 31.08 micrograms per mL). ^{10 7}

Labelling and oversight. A systematic review says oversight of CBD and hemp oils is uneven, creating gaps in quality control and labelling. Many are marketed as THC-free yet trace amounts may be present. ¹²

Rancidity (all four oils). Polyunsaturated fats oxidise more easily than saturated fats (Linus Pauling Institute). Perilla oil is prone to oxidation (2024 review), and the oxidation state of walnut oil varies with raw material, processing and storage (2026 review). The Linus Pauling Institute says fat-soluble antioxidants such as vitamin E play an important role in preventing PUFA oxidation. ^{19 9 14}

Supplement quality in general. No source read tested capsules of these oils for label accuracy, pesticides or heavy metals.

Body	Action	Date
NCCIH, US National Institutes of Health (omega-3 supplements) (United States)	Says side effects of omega-3 supplements are usually mild (unpleasant taste, bad breath, bad-smelling sweat, headache, heartburn, nausea, diarrhoea) and notes ALA is found in plant oils such as flaxseed, soybean and canola and in chia seeds and walnuts. Does not discuss hemp or perilla oil. source	2024-11
NHS (United Kingdom): The vegan diet (United Kingdom)	Lists ground linseed (flaxseed) oil, rapeseed oil, chia seeds, shelled hemp seeds and walnuts as vegan omega-3 sources. This is about foods, not these oils as supplements. source	2026-06-05
NHS (United Kingdom): Food allergy (United Kingdom)	Lists tree nuts such as walnuts among the most common allergic foods. source	2026-08-20
US National Academy of Medicine (Food and Nutrition Board), as tabulated by the Linus Pauling Institute (United States)	Adequate intakes for ALA: males 14 and over 1.6 g a day; females 14 and over 1.1 g; pregnancy 1.4 g; breastfeeding 1.3 g. These are food targets for the public, not advice to take supplements. source	2002 (figures); page updated 2019-05

When to get medical help

Swelling of the face, lips or throat, trouble breathing, wheeze, or a spreading rash after taking any of these oils or eating the seeds: call emergency services.
Unusual bleeding, large bruises, or black or bloody stools or vomit if you take blood thinners: get medical help the same day.
Severe or lasting stomach pain or diarrhoea that does not settle: stop the oil and see a doctor.
Chest pain, sudden weakness on one side or sudden trouble speaking: call emergency services. An oil is not a treatment for these.

Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

What are chia, hemp, perilla and walnut oils?

They are oils pressed from chia seeds, hemp seeds, perilla seeds and walnuts. All four supply ALA, a plant omega-3 fat, and are rich in polyunsaturated fat.

^{19 20}

Which has the most ALA?

Chia oil is described as up to 60% ALA and perilla oil as high in ALA. Hemp seed oil was 9.8 to 14.4% ALA in three samples. Walnut oil gives 1.4 g of ALA per tablespoon, against 7.3 g for flaxseed oil (Linus Pauling Institute).

^{15 4 3 19}

Are they as good as fish oil?

No evidence says so. The body turns only part of ALA into EPA and little into DHA, and experts disagree on whether that is enough. No trial of these oils tested a swap for fish or algae oil.

^{19 1}

Are they good for vegans?

The NHS lists chia seeds, shelled hemp seeds, walnuts and flaxseed oil as vegan omega-3 foods. That is about foods; for direct EPA and DHA without fish, see the algal oil page.

²²

Do they lower cholesterol?

Walnut oil lowered cholesterol and LDL in a 100-person trial in type 2 diabetes, and chia oil did so in a 75-woman trial in obesity. Each is a single trial of blood markers.

^{17 11}

Do they help with diabetes?

One open trial with no placebo found lower HbA1c and fasting blood sugar with walnut oil. It needs confirming, and people with diabetes should ask their care team before changes.

¹⁶

Do they help skin, gut or mood?

One small trial found less eczema dryness and itch with hemp seed oil, one found gut bacteria changes with perilla oil in athletes, and one found fewer high depression scores with perilla oil against a historical control. All are very low certainty.

^{2 8 5}

Can hemp seed oil make me fail a drug test?

Hemp seed oil can carry traces of THC. A review found most studies saw no result above cut-off, but trace levels occurred, and positives came mainly from the product content. Ask a testing body if it matters.

^{10 12 7}

Can they cause allergy?

Seed and tree nut allergies are possible. Perilla seed is a leading cause of seed anaphylaxis in Korean children, chia seed allergy is reported in case reports, and the NHS lists walnuts among common allergic foods. The sources do not say how much allergen the oils carry.

^{6 13 21}

Are they safe with blood thinners?

The Linus Pauling Institute cautions that some seed oils and fish oil may reduce platelet clumping, but it does not name these four oils. Any effect is theoretical. Ask a doctor or pharmacist.

¹⁹

Are they safe in pregnancy or for children?

Trials gave chia oil and perilla oil in pregnancy and reported no adverse effects in the abstracts, but no official statement was found. No trial in children was read. Ask a doctor or midwife.

^{15 5}

How should they be stored?

These oils spoil easily because they are rich in polyunsaturated fat. Follow the label, keep them cool and closed, and do not use oil that smells sharp or bitter.

^{19 9 14}

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-26
Last substantive update: 2026-10-26
How we research: We started from our existing ingredient summary, read the Linus Pauling Institute, NCCIH and NHS pages, checked seed values in a saved copy of USDA data, matched plant names in GBIF, and re-read PubMed abstracts for each study. Only abstracts were read for studies. The NIH Office of Dietary Supplements pages were blocked and are marked unread.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. One perilla study has authors linked to oil companies, as noted.

Sources 24

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

Burdge GC. alpha-Linolenic acid interconversion is sufficient as a source of longer chain omega-3 polyunsaturated fatty acids in humans: An opinion.. Lipids. 2022. PMID 35908848. DOI 10.1002/lipd.12355. (abstract)
Callaway J, Schwab U, Harvima I et al.. Efficacy of dietary hempseed oil in patients with atopic dermatitis.. J Dermatolog Treat. 2005. PMID 16019622. DOI 10.1080/09546630510035832. (abstract)
Floares Oarga D, Obistioiu D, Hulea A et al.. Chemical Profile, Bioactive Constituents and In Vitro Growth Stimulation Properties of Cold-Pressed Hemp Seed Oils from Romanian Varieties: In Vitro and In Silico Evaluation.. Plants (Basel). 2025. PMID 41304617. DOI 10.3390/plants14223465. (abstract)
Guan L, Zhu L, Zhang X et al.. Perilla Seed Oil and Protein: Composition, Health Benefits, and Potential Applications in Functional Foods.. Molecules. 2024. PMID 39598647. DOI 10.3390/molecules29225258. (abstract)
Harauma A, Yoshihara H, Hoshi Y et al.. Effects of Varied Omega-3 Fatty Acid Supplementation on Postpartum Mental Health and the Association between Prenatal Erythrocyte Omega-3 Fatty Acid Levels and Postpartum Mental Health.. Nutrients. 2023. PMID 37892462. DOI 10.3390/nu15204388. (abstract)
Jeong K, Kim E, Gantulga P et al.. Advancing allergen characterization in Perilla seed: an oil body purification approach.. Allergy Asthma Clin Immunol. 2026. PMID 41618458. DOI 10.1186/s13223-026-01012-6. (abstract)
Kacargil CU, Soyturk H, Aydin AA et al.. Determination of cannabinoids in commercial hemp seeds and hemp seed oil products in Turkiye by LC-MS/MS.. Forensic Sci Int. 2026. PMID 41621128. DOI 10.1016/j.forsciint.2026.112836. (abstract)
Kawamura A, Nemoto K, Sugita M. Effect of 8-week intake of the n-3 fatty acid-rich perilla oil on the gut function and as a fuel source for female athletes: a randomised trial.. Br J Nutr. 2023. PMID 35705194. DOI 10.1017/S0007114522001805. (abstract)
Li M, Jiang N, Guo G et al.. Perilla Seed Oil: A Review of Health Effects, Encapsulation Strategies and Applications in Food.. Foods. 2024. PMID 39594031. DOI 10.3390/foods13223615. (abstract)
Lindekamp N, Triesch N, Rohn S, Weigel S. Quantification of sixteen cannabinoids in hemp seed edible oils and the influence of thermal processing on cannabinoid contents and profiles.. Food Addit Contam Part A. 2024. PMID 38588664. DOI 10.1080/19440049.2024.2319270. (abstract)
Oliveira-de-Lira L, Santos EMC, de Souza RF et al.. Supplementation-Dependent Effects of Vegetable Oils with Varying Fatty Acid Compositions on Anthropometric and Biochemical Parameters in Obese Women.. Nutrients. 2018. PMID 30037019. DOI 10.3390/nu10070932. (abstract)
Ovat DY, Bezci E, Balica K et al.. Impact of CBD and hemp oil use on drug test results: a systematic review.. Int J Legal Med. 2026. PMID 41942676. DOI 10.1007/s00414-026-03790-5. (abstract)
Porr C, Vidrighin A, Catana AC et al.. Chia Seed Allergy: Emerging Clinical Evidence, Molecular Allergens, and the Unresolved Question of Cross-Reactivity.. Nutrients. 2026. PMID 42797010. DOI 10.3390/nu18183027. (abstract)
Shen Y, Qian L, Wang Z et al.. Walnut oil from raw material to physiological function: an integrated process-chain perspective on quality, oxidative stability, authentication and health effects.. Food Funct. 2026. PMID 42861681. DOI 10.1039/d6fo03549c. (abstract)
Valenzuela R, Bascunan K, Chamorro R et al.. Modification of Docosahexaenoic Acid Composition of Milk from Nursing Women Who Received Alpha Linolenic Acid from Chia Oil during Gestation and Nursing.. Nutrients. 2015. PMID 26247968. DOI 10.3390/nu7085289. (abstract)
Zibaeenezhad M, Aghasadeghi K, Hakimi H et al.. The Effect of Walnut Oil Consumption on Blood Sugar in Patients With Diabetes Mellitus Type 2.. Int J Endocrinol Metab. 2016. PMID 28115966. DOI 10.5812/ijem.34889. (abstract)
Zibaeenezhad MJ, Farhadi P, Attar A et al.. Effects of walnut oil on lipid profiles in hyperlipidemic type 2 diabetic patients: a randomized, double-blind, placebo-controlled trial.. Nutr Diabetes. 2017. PMID 28394361. DOI 10.1038/nutd.2017.8. (abstract)
. GBIF species match (checked 2026-10-26): Salvia hispanica L. (2926992), Cannabis sativa L. (5361880), Perilla frutescens (L.) Britton (5341394), Juglans regia L. (3054368). . . (full-text)
. Linus Pauling Institute, Oregon State University: Essential Fatty Acids (page updated May 2019). . . (full-text)
. NCCIH (US National Institutes of Health): Omega-3 Supplements: What You Need To Know (last updated November 2024). . . (full-text)
. NHS: Food allergy (last reviewed 20 August 2026). . . (full-text)
. NHS: The vegan diet (last reviewed 5 June 2026). . . (full-text)
. NIH Office of Dietary Supplements: Omega-3 Fatty Acids fact sheet. . . (not-read)
. USDA FoodData Central, SR Legacy (April 2018 release): chia seeds (FDC 170554), hemp seed hulled (FDC 170148), walnut oil (FDC 171030). . . (full-text)

Where to buy

Check the label first. Whatever you buy, look for these:

The amount of the active ingredient per serving, not just the front-label claim
A third-party testing mark (USP, NSF or ConsumerLab)
Other ingredients and allergens
Ask a pharmacist about interactions with your medicines

Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.

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Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.