Gut Health

Nutrients connected to Gut Health

A link means the body needs the nutrient for this, or that low intake is linked to it. It does not mean extra supplements help if your intake is already adequate; each link shows how strong the evidence is.

• Inulin and chicory root fibrePreliminary or mixed

  Inulin acts in the gut: it feeds bacteria (Bifidobacterium rose in trials) and can cause gas and bloating.

• Fibre supplements (psyllium, methylcellulose, calcium polycarbophil and others)Clinically supported

  Bulk-forming fibre adds bulk and fluid to stool and eases constipation (psyllium evidence). Other claims are weaker.

• SennaClinically supported

  Short-term relief of constipation; long use can leave the bowel dependent on laxatives.

• KiwifruitPreliminary or mixed

  Small trials and a 2022 meta-analysis suggest two to three kiwifruit a day may ease constipation (low certainty); larger trials are needed.

• OnionsDocumented risk

  Fructans (FODMAPs) in onion can bother some people with IBS; individual tolerance varies.

• PlumsClinically supported

  Prunes (dried plums) eased mild to moderate constipation in trials; a guideline rates most diet evidence low certainty. Results are for dried plums, not fresh.

• Prunes (Dried Plums)Clinically supported

  Prunes have the best human evidence for easing mild to moderate constipation: one 40-person trial beat psyllium, and a dietitian guideline includes two prune statements, mostly low certainty.

• Gut Health Blends (Probiotic, Fiber, Enzymes)Preliminary or mixed

  The main target of these blends; evidence is strain- and ingredient-specific and mostly for IBS and diarrhea types.

• Lactobacillus and Bifidobacterium probioticsPreliminary or mixed

  Probiotics are taken for gut complaints; specific strains have tentative trial support for some of them. Results belong to the exact strain and condition studied.

• Lactobacillus rhamnosus GGClinically supported

  Same as the digestive system: condition-specific support only, for this strain, not general gut health.

• Lactobacillus reuteri (Limosilactobacillus reuteri)Preliminary or mixed

  Studied for infant colic and childhood diarrhoea with mixed results, for one strain (DSM 17938) only.

• Bifidobacterium (infantis, longum, lactis, breve)Preliminary or mixed

  The trials of Bifidobacterium strains are about bowel symptoms (IBS pain, constipation). Findings are strain-specific and mixed.

• Saccharomyces boulardiiClinically supported

  Studied mainly to prevent diarrhoea linked to antibiotics (S. boulardii CNCM I-745). Results are for this yeast and these uses only, with low certainty in the AGA review; trials for other uses are mixed.

• Bacillus coagulans, Bacillus subtilis and spore-forming probioticsPreliminary or mixed

  The trials of named Bacillus strains were all on gut symptoms. Results are strain-specific and mixed.

• Akkermansia, Faecalibacterium and next-generation probioticsLab or animal research only

  These organisms live in the gut and are being studied as possible future gut-targeted biotherapeutics. Human evidence for supplements is limited.

• Prebiotic fibresPreliminary or mixed

  Fermentable fibres such as inulin and FOS raise Bifidobacterium counts and modestly raise stool frequency in trials, but effects on symptoms are mixed and certainty is low.

• Aloe veraDocumented risk

  Aloe latex taken by mouth can cause abdominal pain, cramps and diarrhea (NCCIH). FDA found inadequate data on safety and effectiveness of aloe ingredients as over-the-counter laxatives.

• FennelPreliminary or mixed

  Same evidence as the digestive system: limited infant colic trials and traditional use only in adults.

• PeppermintClinically supported

  Studied mainly for IBS symptoms with enteric-coated oil; very low certainty evidence.

• Cascara sagradaClinically supported

  Its anthraquinones stimulate bowel movements and change water and salt absorption in the gut, which softens stool. Short-term use only.

• Chicory rootClinically supported

  Chicory inulin raised stool frequency in people with constipation in small trials and a meta-analysis; this applies to inulin, not every chicory product.

• PsylliumPreliminary or mixed

  Used for bowel regularity and IBS; evidence is clearer for constipation.

• CilantroDocumented risk

  Fresh cilantro has been linked to cyclosporiasis, a parasite infection of the small intestine; CDC says washing may not remove the parasite.

• Rhubarb rootClinically supported

  Rhubarb root is a stimulant laxative recognised in the EU for short-term relief of occasional constipation (up to one week). Trials of this use were not found in the sources we read.

• White kidney bean extractDocumented risk

  Raw or undercooked kidney beans contain a lectin that can cause food poisoning with vomiting and diarrhea; this concerns the whole bean, not manufactured extracts.

• Asafoetida (hing)Preliminary or mixed

  IBS meta-analysis listed asafoetida but few findings were repeated.

• Asafoetida (hing)Preliminary or mixed

  Same irritable bowel finding; remedy trials, not food amounts.

• AlfalfaDocumented risk

  Digestive side effects and sprout-related infections are documented; no digestive benefit was shown.

• Prickly ash (northern)Documented risk

  Sources say it may increase stomach acid and should be avoided with ulcers, IBS, ulcerative colitis or Crohn's disease. This is a caution, not a benefit.

• PearsPreliminary or mixed

  Fiber from fruit such as pears is part of eating for regular bowel movements (NIDDK); pear-specific trials were not found.

• DatesPreliminary or mixed

  Dates added stool frequency in a small trial but did not change the gut bacteria groups measured.

• FigsPreliminary or mixed

  Fig syrup and paste were studied for constipation; limited evidence.

• ParsnipsPreliminary or mixed

  Fiber supports digestion in general (NHS); this is not a parsnip-specific finding.

• JicamaPreliminary or mixed

  Inulin-type fibers feed gut bacteria; effects shown for purified fibers, not jicama. Can cause gas or bloating in some people.

• Green PeasDocumented risk

  Pulse meals caused more gut symptoms (gas, bloating) in people with a sensitive gut or IBS.

• Globe ArtichokesPreliminary or mixed

  Inulin-type fibers had prebiotic effects in human trials, but those trials used isolated inulin, not the artichoke vegetable.

• SauerkrautPreliminary or mixed

  A 2025 crossover trial in 87 healthy adults found changes in single gut bacterial species after sauerkraut; the authors concluded the healthy microbiome is rather resilient. No symptom or disease outcome was reported.

• Peppermint OilClinically supported

  IBS capsule trials.

• Senna Tea (Laxative Teas)Documented risk

  Sources warn against continued use because it can weaken normal bowel activity.

• Oat Straw TeaDocumented risk

  Oats are often cross-contaminated with gluten grains; people with celiac disease should ask a clinician and look for a gluten-free label.

• LentilsDocumented risk

  Gas is the most common reported symptom; in lentil trials most people reported none to mild symptoms. Galacto-oligosaccharides are mainly found in beans and pulses (hospital low-FODMAP leaflet).

• Chickpeas (Garbanzo Beans)Documented risk

  Gas is a common effect of pulses; galacto-oligosaccharides are mainly found in beans and pulses (hospital low-FODMAP leaflet), which limits canned chickpeas to 2 tbsp at a meal in its elimination phase.

• Split PeasDocumented risk

  Gas is a common effect of pulses; galacto-oligosaccharides are mainly found in beans and pulses (hospital low-FODMAP leaflet). We read no split-pea-only gas trial.

• Pigeon PeasDocumented risk

  Gas is a common effect of pulses; galacto-oligosaccharides are mainly found in beans and pulses (hospital low-FODMAP leaflet). We read no pigeon-pea-only gas trial.

• Black-Eyed Peas (Cowpeas)Documented risk

  Gas is a common effect of pulses; in three feeding studies black-eyed peas had the lowest share of people reporting more gas in week 1 (19%), falling later.

• Navy BeansDocumented risk

  Extra gas is a common effect; people with irritable bowel syndrome may react more strongly.

• White Beans (Cannellini & Great Northern)Documented risk

  Extra gas is a common effect; people with irritable bowel syndrome may react more strongly.

• Lima BeansDocumented risk

  Extra gas is a common effect; people with irritable bowel syndrome may react more strongly.

• Mung BeansDocumented risk

  Extra gas is a common effect; people with irritable bowel syndrome may react more strongly.

• Adzuki BeansDocumented risk

  Extra gas is a common effect; people with irritable bowel syndrome may react more strongly.

• Bean Sprouts (Mung & Lentil Sprouts)Documented risk

  Sprouts are a documented source of foodborne illness outbreaks, including mung bean sprouts in a 1988 UK Salmonella outbreak.

• Cranberry Beans (Borlotti)Documented risk

  Raw or undercooked beans carry lectins that can cause vomiting and diarrhea, and beans ferment in the gut to cause gas and bloating in some people. Both are documented but avoidable with cooking and, for gas, smaller portions.

• Tepary BeansDocumented risk

  Raw tepary beans have very high lectin activity per the plant reference and gas-causing sugars; cooking reduces the lectin, and gas is common with beans.

• Urad Dal (Black Gram)Documented risk

  Raw legumes carry lectins and other antinutrients that cooking reduces, and beans ferment in the gut to cause gas in some people. No black gram poisoning report was read.

• Moth Beans (Matki)Documented risk

  Raw legumes carry lectins and other antinutrients that cooking reduces, raw sprouts carry a bacterial risk, and beans ferment in the gut to cause gas in some people.

• Horse Gram (Kulthi)Documented risk

  Raw seed contains lectins and trypsin inhibitors that cooking reduces; beans can also cause extra gas.

• Bambara GroundnutDocumented risk

  Raw seeds hold trypsin inhibitors, tannins, phytate and oxalate that cooking reduces; beans can also cause extra gas.

• Hyacinth Beans (Lablab)Documented risk

  Mature dry seeds contain cyanogenic glycosides, lectins and trypsin inhibitors that cooking reduces; beans can also cause extra gas.

• Winged BeansDocumented risk

  Raw dry seeds contain lectins and trypsin inhibitors that heat destroys; beans can also cause extra gas.

• Jack Beans (Caution)Documented risk

  Raw seeds contain lectin, canavanine and other toxic factors that are only partly removed by heat in animal studies; a related bean has caused poisoning when undercooked.

• Prune JuicePreliminary or mixed

  Prune juice reduced hard stools in one trial of adults with chronic constipation; limited evidence.

• CarrageenanPreliminary or mixed

  Safety debate for gut inflammation; no large trial.

• Diosmectite (Smectite)Clinically supported

  Used for acute diarrhea in children, with low-certainty evidence.

• Coconut Shell CharcoalDocumented risk

  Nausea, vomiting, constipation and blockage cautions are documented.

• Eating Clay (Geophagy)Documented risk

  Blockage and infection are listed complications of eating non-food items.

• Castor OilClinically supported

  Stimulant laxative action when swallowed; not a general gut-health product.

• Vitamin DDeficiency link

  Poor absorption in gut disorders can lower vitamin D levels. This is about gut disease affecting vitamin D, not vitamin D treating the gut.

• Lactobacillus acidophilus and the acidophilus groupPreliminary or mixed

  Named acidophilus strains have been tested for diarrhoea, C. difficile and IBS with low-certainty results; the species alone has little evidence.

• TurmericPreliminary or mixed

  Traditional herbal use in the European Union supports turmeric for mild digestion problems such as fullness and gas in adults. Studies hinted at a benefit, but their design flaws meant firm conclusions could not be drawn.

• Slippery elmPreliminary or mixed

  Same traditional gut use; evidence is thin and from a combination product.

• Turkey tailPreliminary or mixed

  One small trial of PSP showed gut-bacteria changes described as prebiotic-like.

• Almond mushroom (Agaricus subrufescens)Preliminary or mixed

  Two 21-day single-blinded trials of a branded extract (50 people each) reported symptom improvements in ulcerative colitis and Crohn's disease; only the ulcerative colitis trial separated from placebo in the abstract.

• Rose petalsPreliminary or mixed

  Some benefit for constipation symptoms in a 2025 review of 13 studies.

• Bamboo mushroomLab or animal research only

  A polysaccharide restored gut bacteria and gut-barrier proteins in antibiotic-treated mice. No human data.

• CarawayPreliminary or mixed

  The EU accepts caraway tea for bloating and gas as a traditional use only; trials tested a peppermint-plus-caraway oil capsule.

• Lotus seed (lian zi)Documented risk

  A supplier reference lists constipation and abdominal distention as reasons not to use lotus seed; two of 20 people in a small trial reported constipation. Evidence is limited.

• Fennel seedPreliminary or mixed

  Same evidence as the digestive system.

• WheatgrassPreliminary or mixed

  Used for active ulcerative colitis symptoms; one small one-month trial was positive and a 2013 review called the studies limited.

• YaconPreliminary or mixed

  Prebiotic effect on gut bacteria and stool habits in small studies.

• Perilla (shiso)Preliminary or mixed

  Pilot trial for stomach and bowel discomfort; small and preliminary.

• Korean mint (huo xiang)Preliminary or mixed

  A formula trial in IBS-D reported relief; the single plant has not been tested in people for gut health.

• Citrus Fruits (overview)Established role

  Whole citrus provides dietary fiber; juice has less.

• BananasPreliminary or mixed

  Green banana in porridge helped children with persistent diarrhoea in one trial; resistant starch effects in the gut were seen in mice only.

• FumitoryPreliminary or mixed

  Traditionally used for fullness and gas. The one IBS trial found no benefit over placebo, so support is limited.

• Daikon RadishPreliminary or mixed

  Fermented vegetable foods are linked with gut-related outcomes in observational work; daikon alone was not studied.

• Chili PeppersDocumented risk

  Chili can bring on burning or pain in sensitive guts; long-term effects were mixed in small trials.

• Fennel BulbPreliminary or mixed

  Fiber from vegetables supports regular bowel habits per the NHS; this is general fiber advice, not a fennel bulb result.

• Onion powderDocumented risk

  Onion is high in fructans that can worsen IBS symptoms in some people; measured in fresh onion, not powder.

• Tigernuts (Chufa)Preliminary or mixed

  Small horchata study of gut bacteria.

• Anise TeaPreliminary or mixed

  Same traditional-use acceptance for bloating and gas.

• Whole Wheat & Wheat BerriesPreliminary or mixed

  Fiber from grains adds stool bulk (general cereal fiber evidence). Effects on gut bacteria from wheat types are only in small trials.

• SpeltPreliminary or mixed

  Fiber from grains adds stool bulk (general cereal fiber evidence). Effects on gut bacteria from wheat types are only in small trials.

• Farro (Emmer)Preliminary or mixed

  Fiber from grains adds stool bulk (general cereal fiber evidence). Effects on gut bacteria from wheat types are only in small trials. Not farro-specific.

• Khorasan Wheat (Kamut)Preliminary or mixed

  Fiber from grains adds stool bulk (general cereal fiber evidence). Effects on gut bacteria from wheat types are only in small trials.

• BulgurPreliminary or mixed

  Fiber from grains adds stool bulk (general cereal fiber evidence). Effects on gut bacteria from wheat types are only in small trials.

• FreekehPreliminary or mixed

  Fiber from grains adds stool bulk (general cereal fiber evidence). Effects on gut bacteria from wheat types are only in small trials. Not freekeh-specific.

• Water Kefir (Tibicos)Preliminary or mixed

  Small trial: gut bacteria shifted; mild gas and bloating common.

• KombuPreliminary or mixed

  Changes in gut bacteria in one trial.

• Whey Protein PowderDocumented risk

  Lactose in less-filtered whey can cause digestive symptoms in people who are lactose intolerant; amounts by product were not found in the sources read.

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