Nervous System

Nutrients connected to Nervous System

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.

• Vitamin B1 (thiamin)Established role

  Thiamin is needed for a healthy nervous system, and severe lack causes nerve damage. Extra supplements have not been shown to help when intake is adequate.

• Vitamin B3 (niacin)Established role

  Niacin helps keep the nervous system healthy. Untreated severe deficiency can cause nerve damage and mental confusion.

• Vitamin B6Documented risk

  High-dose B6 supplements can cause nerve damage in the arms and legs; the effect often improves after stopping but can be permanent.

• Vitamin B12Established role

  B12 helps keep the nervous system healthy. Low levels can cause numbness, tingling and balance problems, which can be permanent if untreated.

• MagnesiumEstablished role

  Magnesium is needed for normal nerve function. Low levels can cause numbness, tingling and seizures.

• PotassiumEstablished role

  Potassium supports nerve function. Low or high blood potassium can cause weakness, tingling or numbness.

• ManganeseDocumented risk

  Too much manganese can harm the nervous system, causing Parkinson-like signs that are not identical to Parkinson's disease. This is a safety signal, not a benefit.

• TyrosineEstablished role

  The body uses tyrosine to make dopamine, norepinephrine and epinephrine, which the nervous system relies on. This normal role is not proof that extra supplements help.

• Caffeine supplementsClinically supported

  Caffeine is a central nervous system stimulant; its alertness effect lasts roughly four to six hours.

• Caffeine plus L-theanine and brain formulasClinically supported

  Caffeine stimulates the central nervous system; this also explains its jitter and sleep effects.

• GABA supplementsEstablished role

  The body's own GABA is the main calming messenger in the brain. This does not show that GABA taken by mouth reaches or acts on the brain.

• NeemDocumented risk

  Swallowing neem oil has caused seizures, coma and brain damage in case reports; this is a documented harm, not a benefit.

• WormwoodDocumented risk

  Thujone is neurotoxic and causes convulsions in animals at high doses; concentrated wormwood oil is linked to seizures. This is a caution, not a benefit.

• LobeliaDocumented risk

  Higher amounts of lobeline depress the central nervous system (MSK).

• HyssopDocumented risk

  Hyssop essential oil is described as toxic to the nervous system and linked to seizures (e-lactancia); a 1999 report links several essential oils to seizures. Avoid the oil, especially with epilepsy.

• TansyDocumented risk

  Thujone in tansy oil can cause convulsions and loss of consciousness; this is a harm, not a benefit.

• YohimbeDocumented risk

  Yohimbine stimulates the noradrenergic system, causing anxiety, insomnia and tremors; seizures have been reported (MSK, NCCIH).

• KratomDocumented risk

  Kratom's main compounds act on opioid receptors in the brain. This underlies dependence, withdrawal, seizure and overdose concerns; no medical use is approved.

• Star aniseDocumented risk

  Star anise tea has caused seizures and other nerve effects in infants, partly through toxic Japanese star anise mixed into supplies.

• Thuja (northern white cedar)Documented risk

  Thujone in thuja can cause convulsions; the EU herbal committee calls it a neurotoxicant. This is a safety concern, not a benefit.

• False MorelDocumented risk

  Nerve effects (dizziness, ataxia, seizures in severe cases) are documented; MMH lowers GABA production by tying up active vitamin B6.

• EpazoteDocumented risk

  Case reports describe coma, seizures and encephalopathy after epazote oil or strong infusions, especially in children.

• KhatDocumented risk

  Khat contains stimulant chemicals; the DEA reports dependence, mania and psychosis with chronic use. Whether khat is the cause of psychiatric illness is debated.

• MayappleDocumented risk

  Confusion, seizures, coma and nerve damage that can be permanent are reported after poisoning (IPCS).

• Star Fruit (Carambola)Documented risk

  In people with kidney disease star fruit has caused hiccups, confusion and seizures. The suspected toxin is caramboxin; the mechanism evidence is from animals and lab work.

• Chinese five-spiceDocumented risk

  Star anise tea has made infants ill, with seizures reported, and FDA advised against it. This is about tea, not a pinch in cooking.

• Aconite (monkshood)Documented risk

  Aconite alkaloids disrupt sodium channels in nerves and heart muscle; poisoning causes numbness or tingling around the mouth and limbs, and seizures have been reported.

• Belladonna (deadly nightshade)Documented risk

  Belladonna's alkaloids can cause confusion, agitation, hallucinations and, in severe cases, seizures. This is a poisoning risk, not a benefit.

• Angel wingDocumented risk

  The illness is a neurological one: encephalopathy with seizures.

• Cassava (Yuca)Documented risk

  Konzo, a lasting leg paralysis, is linked to long-term reliance on poorly processed bitter cassava; acute cyanide poisoning also affects the nervous system. This is a safety link, not a benefit.

• Poison hemlockDocumented risk

  Poison hemlock affects nerves and muscles: nicotine-like overstimulation then paralysis. This is a poisoning, not a benefit.

• Deadly fibrecapDocumented risk

  Muscarine acts on the automatic (parasympathetic) nerve receptors; tremor and restlessness were reported in the hospital series.

• Ginkgo NutsDocumented risk

  Ginkgo seeds can cause seizures and confusion through ginkgotoxin, mostly after many seeds and especially in children.

• Tea Tree OilDocumented risk

  Swallowed tea tree oil can cause confusion, unsteadiness and coma (NCCIH).

• Eucalyptus OilDocumented risk

  Swallowed oil can cause seizures; skin use has caused seizures in a child.

• Nutmeg OilDocumented risk

  Case reports and a poison-center series document drowsiness, agitation, coma and seizures after large nutmeg intakes (spice).

• Camphor Oil (Dangers)Documented risk

  Seizures, breathing depression and coma are described after swallowing, and seizures after heavy skin use in young children.

• Hyssop OilDocumented risk

  Hyssop oil is among oils that reviews and case reports link to seizures, mostly after swallowing.

• Sage Oil (Dalmatian and Spanish)Documented risk

  Sage oil has caused seizures, including in a baby and a 5-year-old; thujone and camphor are the suspected cause.

• Star Anise TeaDocumented risk

  Infants given star anise tea have had seizures and other nervous-system reactions, linked to toxic Japanese star anise contamination.

• Wormwood Tea (Dangers)Documented risk

  Thujone causes convulsions in animals; poisoning with thujone-rich oil reported in people.

• Borax (Sodium Borate)Documented risk

  Seizures, confusion and coma are described after large or long-term swallowing, especially in infants.

• B-Complex FormulasDocumented risk

  High B6 intake can cause nerve damage (numbness in the arms and legs); EFSA calls this well established.

• Vitamin EDeficiency link

  Severe, long-lasting vitamin E deficiency damages the nervous system. This is seen with malabsorption and inherited disorders, not usually in people eating a normal diet.

• Vitamin B2Established role

  The NHS says riboflavin helps keep the nervous system healthy.

• Vitamin B9 (folate and folic acid)Clinically supported

  Folic acid helps the baby's brain and spinal cord form normally in early pregnancy (neural tube). High doses can also hide B12 deficiency, which can harm nerves.

• CalciumEstablished role

  Calcium helps nerves send and receive messages.

• IodineDeficiency link

  Enough iodine in pregnancy and early life supports normal brain development; deficiency can impair it. This is about deficiency, not extra supplements.

• CopperEstablished role

  Copper helps keep nerves healthy, and low copper can affect the nervous system. Extra copper has not been shown to help people who already get enough.

• PhosphorusEstablished role

  Phosphorus supports nerve signalling. Severely low blood phosphate can cause confusion and seizures, but this is a medical emergency, not a supplement question.

• BCAAs (leucine, isoleucine, valine)Documented risk

  In maple syrup urine disease these amino acids build up and are toxic to the brain and other organs, so people with it should avoid BCAA products unless their metabolic team advises.

• GlycineEstablished role

  Glycine takes part in normal nerve-cell function. This is a normal role, not proof that extra glycine helps.

• TaurineLab or animal research only

  Taurine is one of the most abundant amino acids in the brain and is involved in nervous system development and cell protection. This is lab and animal-based understanding; it does not show that extra supplements help.

• Fish oilEstablished role

  The NHS notes omega-3 supports a baby's nervous system development in pregnancy and breastfeeding. This is a normal role of omega-3; it does not show extra supplements help people who already eat enough.

• Omega-3 fatty acids (ALA, EPA and DHA)Established role

  DHA is a major building block of the brain and retina. This is its normal role; it does not show that extra supplements improve brain function.

• Alpha-lipoic acidPreliminary or mixed

  Studied for nerve symptoms (pain, burning, tingling in the feet) in diabetes. Results are mixed by mouth and more favourable but lower quality by IV; NCCIH calls the possible benefit weak.

• Citicoline and alpha-GPCPreliminary or mixed

  Choline-containing compounds feed membrane and nerve-messenger pathways, but benefits for the nervous system in healthy people are not shown.

• PhosphatidylserineEstablished role

  PS is a normal part of nerve-cell membranes and the body makes it. Whether a supplement adds anything is unproven.

• Choline (supplement forms: bitartrate, phosphatidylcholine and others)Established role

  Choline is used to make acetylcholine, a messenger between nerve cells, and cell-membrane phospholipids.

• Bacopa monnieriPreliminary or mixed

  Cognitive tests are the main outcomes studied; effects on the nervous system itself are not established.

• Botanical and mushroom nootropicsPreliminary or mixed

  Studied for cognitive outcomes; evidence is limited and mixed.

• Huperzine A and other herbal cholinesterase productsLab or animal research only

  It blocks an enzyme in the nervous system, as some dementia medicines do, which is why medicine questions arise.

• SageDocumented risk

  Thujone in common sage is reported to be neurotoxic; large amounts of sage oil have caused seizures.

• St. John's wortDocumented risk

  With certain antidepressants or other serotonin-affecting drugs it may increase serotonin-related side effects, which can be serious.

• PassionflowerPreliminary or mixed

  Used for calming and sleep; may cause drowsiness, dizziness and confusion, and might slow the nervous system with anesthesia.

• ValerianDocumented risk

  Valerian may add to the sedating effect of alcohol or sedatives, and stopping suddenly after long use may cause withdrawal effects.

• FeverfewPreliminary or mixed

  Used to try to prevent migraine. A Cochrane review found mixed, low-quality evidence; the EU approval rests on traditional use.

• ButterburPreliminary or mixed

  A specific root extract may reduce how often migraines occur in adults, according to NCCIH; evidence is limited and the 2012 neurology recommendation was withdrawn over safety.

• HorsetailDocumented risk

  Horsetail contains thiaminase, which breaks down thiamine; Canada requires thiaminase-free products because of possible irreversible brain damage in people already thiamine deficient.

• EucalyptusDocumented risk

  Swallowed eucalyptus oil can cause drowsiness, seizures and coma, and skin use has caused seizures in children.

• KavaDocumented risk

  Kava can cause drowsiness and impaired reflexes, and adds to the effect of alcohol and sedatives such as benzodiazepines.

• Blue lotusDocumented risk

  Blue lotus products have been linked to sedation, confusion and changed perception in emergency cases; the plant's alkaloids are reported to act on dopamine pathways. Benefits for the nervous system were not shown.

• GuaranaDocumented risk

  As a caffeine source guarana stimulates the central nervous system; insomnia and, at high amounts, seizures are reported.

• Wild lettuceDocumented risk

  Eaten, wild lettuce caused drowsiness, loss of consciousness, agitation and hallucinations in eight reported patients.

• Graviola (soursop)Documented risk

  Observational studies link regular graviola fruit, juice and leaf-tea use to a severe parkinsonism in the French Caribbean, and lab work shows nerve-cell toxicity. The cause is not proven.

• PennyroyalDocumented risk

  Published poisoning cases include seizures, brain swelling and severe epilepsy after exposure, including two infants.

• RueDocumented risk

  Convulsions and dizziness are listed among the effects of swallowing rue. A safety caution, not a benefit.

• Mucuna pruriens (velvet bean)Preliminary or mixed

  The seed contains levodopa, and small trials in Parkinson's found movement benefit; the 2025 review calls the evidence limited. It is a drug-strength source, not a general nerve tonic.

• Griffonia (5-HTP source)Documented risk

  5-HTP raises serotonin and can combine dangerously with antidepressants and other serotonin-raising medicines.

• Betel nut (areca nut)Documented risk

  Reviews describe dependence driven by arecoline acting on brain chemical systems. This is a risk, not a benefit.

• MorelDocumented risk

  Neurological symptoms such as dizziness and unsteadiness were common after morel ingestion (53.3% in France; 65.4% in a review of 52 ingestions).

• Bala (country mallow)Documented risk

  NCCIH links ephedra to seizure and psychosis; Sida cordifolia is named by the FDA as another ephedrine source. Bala-specific data not found.

• Poke root (pokeweed)Documented risk

  MedlinePlus lists seizures, headache and loss of consciousness among poisoning symptoms; Ohio State lists convulsions with large amounts.

• Albizia (mimosa tree bark)Documented risk

  A consumer drug reference warns of excessive sleepiness and added effects with sedating medicines. This is a caution, not proof of benefit.

• Sarpagandha (Indian snakeroot)Documented risk

  Label and case report describe depression and parkinsonism with reserpine, including from a herbal product.

• Tagara (Indian valerian)Documented risk

  Tagara is used for its calming effect on the nervous system, so it may add to drowsiness from alcohol and sedatives. This is carried over from common valerian; no tagara study was found.

• NutmegDocumented risk

  Large amounts have caused delirium, agitation and drowsiness in poison-center and case reports.

• MaceDocumented risk

  A child who ate six dried pieces of mace became very drowsy and stiff; large amounts of mace or nutmeg can affect the nervous system. This is not about cooking amounts.

• Apricot kernel (bitter)Documented risk

  Cyanide released from amygdalin can cause confusion, seizures, coma and nerve damage (NCI, FDA).

• Sophora flavescens (ku shen)Documented risk

  Matrine caused brain changes and impaired coordination in mice and harmed nerve-like cells in the laboratory. No human neurotoxicity cases were found; dizziness occurred in poisoning cases.

• LycheeDocumented risk

  The Muzaffarpur outbreak was an acute toxic brain illness in children linked to lychee toxins; it is a regional outbreak, not a general finding.

• OleanderDocumented risk

  Dizziness, confusion, drowsiness and fainting are listed symptoms of oleander poisoning. This is a warning, not a use.

• Lily of the valleyDocumented risk

  Confusion, drowsiness, headache and weakness are listed after poisoning.

• Trichosanthes (tian hua fen)Documented risk

  Injected purified trichosanthin caused confusion, dementia or coma in some HIV trial patients. This is not shown for the dried root.

• Tender nesting polyporeDocumented risk

  Double vision, nystagmus, balance problems and hallucinations were reported; a review links the fungus to delayed encephalopathy.

• Poppy SeedsDocumented risk

  Morphine from contaminated seeds, mainly in tea from unwashed seeds, can affect consciousness; BfR describes impaired consciousness in the worst case.

• Anise and Star Anise OilDocumented risk

  Star anise tea caused seizure-like events in infants, linked to Japanese star anise contamination; the oil itself was not reported.

• Sage TeaDocumented risk

  Thujone is neurotoxic and can cause seizures at high amounts.

• Valerian TeaDocumented risk

  Valerian can cause drowsiness, may impair driving, and should not be combined with alcohol or sedatives (NIH, EMA).

• Kava, Kratom and Blue Lotus TeasDocumented risk

  Same neurological effects described by FDA and the blue lotus case series.

• Pennyroyal Tea (Dangers)Documented risk

  Seizures, brain swelling and severe epilepsy have been reported.

• Wild Lettuce TeaDocumented risk

  Eaten wild lettuce caused confusion, agitation, hallucinations and loss of consciousness in 8 hospital patients.

• Mad Honey (Grayanotoxin Honey)Documented risk

  EFSA lists convulsions, confusion and fainting; the toxin acts on sodium channels and vagal tone.

• Multivitamins for Adults Over 50Documented risk

  Low B12 and high B6 can affect nerves, and folic acid above 1 mg may hide B12 deficiency.

• Pre-Workout SupplementsDocumented risk

  Caffeine jitters and anxiety; beta-alanine tingling (not harmful per ISSN).

• Energy and Focus BlendsPreliminary or mixed

  MedlinePlus says caffeine stimulates the central nervous system; too much can cause restlessness and insomnia. B6 in excess can harm nerves (NHS).

• Vitamin B5Deficiency link

  A lack of pantothenic acid is very rare, but it can cause tingling in the feet. Tingling has many causes, so it is not a way to diagnose deficiency.

• Vitamin B7Deficiency link

  In the inherited disorder biotinidase deficiency, the body cannot recycle biotin, and untreated babies can have seizures, low muscle tone and developmental delay. This is a rare genetic condition, not everyday low intake.

• IronPreliminary or mixed

  The NHS says restless legs syndrome is thought to be tied to iron and dopamine levels, and lists iron deficiency anaemia among linked conditions. The link is a suspected one.

• SeleniumDocumented risk

  Selenosis can include irritability and mild nerve damage.

• MolybdenumDeficiency link

  In the rare inherited disorder molybdenum cofactor deficiency, the body cannot use molybdenum and newborns have seizures and developmental delay. This is a genetic condition, not caused by diet.

• CarnitinePreliminary or mixed

  Acetyl-L-carnitine has been studied for painful nerve damage with some pain reduction in a few trials, but a Cochrane review found no benefit for dementia.

• Beta-alanineDocumented risk

  Tingling (paresthesia) is the best-known effect; the ISSN found no evidence it is harmful and it fades within about an hour or two.

• SaffronDocumented risk

  Headache, dizziness, fatigue, vivid dreams and insomnia were commonly reported in trials, and people with psychiatric conditions may be more sensitive.

• Lemon balmPreliminary or mixed

  Used for its calming effects; lab studies suggest action on brain signalling, human evidence is limited.

• California poppyLab or animal research only

  The extract appears to act on benzodiazepine receptors in mice. This is animal evidence only.

• Asian ginsengDocumented risk

  Insomnia is the common side effect; case reports of mania.

• Panax notoginsengPreliminary or mixed

  Trials of a saponin injection added to standard care for bleeding in the brain reported better outcomes. These findings are for a hospital injection used with standard care, not supplements.

• TribulusDocumented risk

  One case report of seizure alongside liver and kidney injury; animal work links tribulus to GABA receptor effects.

• Blue cohoshDocumented risk

  The nicotine-like alkaloid N-methylcytisine caused fast heartbeat, sweating and muscle twitching in one poisoning case.

• CorydalisDocumented risk

  Drowsiness and dizziness are listed as common side effects, and extra sedation is possible with other sedating medicines.

• Lion's manePreliminary or mixed

  Memory test results come from small trials; nerve findings are laboratory work.

• TremellaPreliminary or mixed

  One small 8-week trial in adults with memory complaints reported benefit versus placebo; it needs repeating.

• GuayusaDocumented risk

  Caffeine can cause jitteriness and tremor; both appeared in trials.

• AjwainPreliminary or mixed

  A 10% cream helped burning-foot symptoms in one small trial but not chemotherapy nerve symptoms in another.

• Cinchona barkDocumented risk

  Confusion and nerve-related symptoms are part of cinchonism.

• Gastrodia (tian ma)Preliminary or mixed

  Used in Chinese medicine for headache and dizziness; human trials tested the purified compound gastrodin for migraine and for delirium after heart surgery, not the whole herb.

• ShankhpushpiLab or animal research only

  Studied for nerve-related effects in cells and animals; no human evidence of benefit was found.

• Horseradish and wasabiPreliminary or mixed

  One small wasabi extract trial reported better memory in older adults.

• Ajwain (carom seed)Preliminary or mixed

  One trial of a 10% skin cream found less burning foot pain; a second trial in people with chemotherapy nerve symptoms found no benefit. Not shown for seeds in food.

• Oat straw (milky oats)Preliminary or mixed

  Used traditionally for mild stress and sleep; thinking-test results are mixed.

• BlueberriesPreliminary or mixed

  Memory findings are limited to older adults with mild cognitive decline; healthy adults showed no clear effect.

• Wild indigoDocumented risk

  The main alkaloid, cytisine, acts on nicotine-type nerve receptors; poisoning signs include tremors and weakness in animals and children per a poisoning guide.

• Lettuce (Romaine & Leaf)Preliminary or mixed

  Higher green leafy vegetable intake was linked to slower cognitive decline in one cohort of older adults; observational and not specific to lettuce.

• Scotch broomDocumented risk

  Poisoning is described with dizziness, headache, sleepiness and widened pupils.

• Sulphur tuftDocumented risk

  Nerve paralysis is listed among the symptoms in one review and was seen in mice given fasciculol; human detail is lacking.

• Common earthballDocumented risk

  Dizziness, short losses of awareness and myoclonia were seen in a minority of French cases; the cause is unidentified.

• Black horehoundPreliminary or mixed

  Sedative-like effects in animals and one open human study; no controlled trials of the herb alone were read.

• Chinese arborvitae seed (bai zi ren)Lab or animal research only

  Mouse work links seed extracts to serotonin and GABA pathways; no human data found.

• Kola NutsDocumented risk

  Caffeine overstimulation (restlessness, jitters, sleep problems) is listed as a possible effect.

• Corn Masa & Corn TortillasDeficiency link

  Pellagra, caused by niacin deficiency, includes poor mental function (MedlinePlus); lime-treated corn prevents the bound-niacin problem.

• MCT OilPreliminary or mixed

  MCT ketogenic diets are used under medical care for epilepsy; ketones are brain fuel.

• Oral Rehydration SaltsDocumented risk

  A mixing error caused very high blood sodium, a seizure and brain swelling in one infant case.

• Sleep Blends (Melatonin, Magnesium, L-Theanine, Herbs)Preliminary or mixed

  Sleep ingredients act on sleep-wake control; sedating effects can add up with alcohol or sedatives.

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