Can Vitamin Deficiency Cause Seizures?

Vitamin deficiency can absolutely cause seizures, and the link is better established than most people realize. Several B vitamins, vitamin D, and even vitamin E have documented roles in seizure development when levels drop low enough. The mechanism varies by vitamin: some affect how the brain makes its calming chemical signals, others throw off calcium levels, and still others damage the protective coating on nerve fibers. The connection is strongest in infants and young children, but adults are not immune, especially in specific circumstances that deplete vitamins faster than the body can replace them.

Vitamin B6 Has the Strongest and Oldest Connection to Seizures

Of all the vitamins tied to seizures, B6 (pyridoxine) has the most robust evidence and the longest history. The active form of B6 serves as a required helper molecule for the enzyme that produces GABA, the brain’s primary inhibitory neurotransmitter. When B6 runs low, GABA production drops, and without enough GABA to keep neurons in check, electrical activity in the brain can spiral into a seizure.¹ This is not a theoretical concern. In adults, B6 deficiency from dietary gaps, liver disease, pregnancy, or certain medications has caused seizures that resolved with supplementation.²

One well-known trigger is isoniazid, a tuberculosis drug that interferes with B6 metabolism. An isoniazid overdose can cause rapid-onset seizures and dangerous metabolic changes, and pyridoxine is the established treatment for reversing them.³ Emergency departments stock intravenous pyridoxine specifically for this scenario, and it is one of the clearest examples of a vitamin acting as a direct antidote for seizure activity.

In newborns and infants, there are also rare genetic conditions where the body cannot properly use or recycle B6 even when dietary intake is adequate. These children develop severe, medication-resistant seizures that respond dramatically to high-dose pyridoxine. When a baby presents with unexplained seizures that do not respond to standard anti-seizure drugs, a pyridoxine trial is a standard part of the workup.⁴

Vitamin D Causes Seizures Through Calcium, Not Directly

Vitamin D does not act on neurons the way B6 does. Instead, it controls how much calcium your body absorbs and keeps in circulation. When vitamin D drops very low, blood calcium follows it down, and low calcium (hypocalcemia) makes nerve cells fire more easily. The result can be muscle twitching, spasms, and full seizures. This is especially dangerous in infants, whose calcium needs are high relative to their body size and whose stores are thin.

A study comparing infants with hypocalcemic seizures to healthy controls found that 90% of affected infants had severe vitamin D deficiency, with blood levels below 10 ng/mL. Their mothers were also deficient, at a rate of 85%, compared to 50% in the control group.⁵ Breastfed infants born to mothers with very low vitamin D are at particular risk because breast milk alone does not supply enough vitamin D to compensate, and dietary or cultural factors that limit sun exposure in the mother compound the problem.⁶

The practical implication here is that vitamin D-related seizures are almost always treatable and preventable. Correcting the vitamin D deficit restores calcium, and the seizures stop. But the path is indirect: if your vitamin D is merely low rather than severely deficient, and your calcium is normal, a seizure from this mechanism is unlikely. The seizure threshold involves calcium, not vitamin D per se.

Vitamin B12 Deficiency and the Developing Brain

B12 deficiency can cause seizures, though the mechanism is less straightforward than with B6. B12 is essential for maintaining the myelin sheath that insulates nerve fibers and for producing certain neurotransmitters. When B12 drops low enough, demyelination and direct neuronal damage can follow. In infants, whose nervous systems are still developing rapidly, even moderate deficiency can have outsized effects.

A study of children presenting with their first unprovoked seizure found B12 deficiency in the patient group, with seizure types ranging from generalized tonic-clonic events to more unusual patterns like infantile spasms.⁷ Separately, case reports have documented infants developing infantile spasms, a particularly severe seizure type, from B12 deficiency that traced back to the mother’s nutritional status.⁸

One striking case involved an 11-month-old with progressive seizures, developmental regression, and failure to thrive. The child’s mother turned out to have undetectable B12 levels from previously undiagnosed pernicious anemia, an autoimmune condition where the body cannot absorb B12. Once the child received B12 supplementation, metabolic abnormalities corrected and neurological function improved across the board.⁹ Long-term brain imaging in cases like these can show lasting structural changes, including reduced myelin and smaller-than-expected brain structures, even after treatment.¹⁰ The message is that while supplementation can reverse acute seizures, delayed treatment risks permanent neurological damage.

When Folate Cannot Reach the Brain

Folate deficiency linked to seizures is a slightly different story from the other vitamins. Ordinary dietary folate deficiency rarely causes seizures on its own. The seizure connection becomes important when there is a defect in folate transport, specifically the system that moves folate from the bloodstream across the barrier into the brain and spinal fluid. In people with mutations in the FOLR1 gene, which encodes the folate receptor on this barrier, the brain ends up starved of folate even when blood levels look normal.

This condition, called cerebral folate deficiency, typically shows up in early childhood with seizures that resist standard anti-seizure medications, along with problems with coordination, movement, and cognitive development.¹¹ The seizures can be intractable, meaning conventional drugs do not control them, but folinic acid (a form of folate that can bypass the broken transport system) often helps significantly.¹² A separate but related transport defect involves the proton-coupled folate transporter, which causes both systemic and cerebral folate deficiency and also leads to seizures and developmental delay.¹³

These are rare conditions, but they matter because they are treatable. A child with drug-resistant epilepsy whose spinal fluid shows low folate levels may have a condition that responds beautifully to a vitamin supplement. Missing the diagnosis means years of unnecessary seizures and neurological decline.

Thiamine, Biotin, and Vitamin E

Beyond the B6-D-B12-folate group, a few other vitamins have documented links to seizures, though the clinical scenarios tend to be narrower.

Thiamine (B1) deficiency is best known for causing Wernicke’s encephalopathy, a condition involving confusion, eye movement abnormalities, and unsteady gait. Seizures are not the hallmark feature, but they do occur. In non-alcoholic patients with Wernicke’s encephalopathy, most seizures have been generalized convulsive events, thought to result from abnormal brain metabolism caused by the thiamine deficit.¹⁴ Brain MRI in these patients typically reveals a distinctive pattern of symmetric signal changes in the thalamus, mammillary bodies, and areas around the brain’s fluid-filled channels.¹⁵

Biotin deficiency causes seizures through a different pathway. An inherited condition called biotinidase deficiency prevents the body from recycling biotin, and seizures are the most common initial symptom, sometimes appearing before any skin or metabolic signs.¹⁶ This is why newborn screening programs in many countries test for biotinidase deficiency: catching it early and supplementing biotin prevents seizures and brain damage entirely.

Vitamin E deficiency and seizures overlap in a rare genetic condition called ataxia with vitamin E deficiency (AVED). A case from northern Norway documented a patient who developed progressive coordination problems and epilepsy starting at age five, caused by mutations that impaired vitamin E handling. When vitamin E supplementation was finally started 25 years later, seizures and other neurological problems stopped progressing.¹⁷ Vitamin E protects neuronal membranes from oxidative damage, so when levels are chronically absent, neurons accumulate damage that can eventually become irreversible.

Why Maternal Nutrition Matters So Much for Infant Seizures

A recurring theme across many of these vitamins is that the mother’s nutritional status during pregnancy and breastfeeding directly determines whether the infant is at risk. Babies are born with whatever stores they accumulated across the placenta, and exclusively breastfed infants depend entirely on the mother’s current levels for their ongoing supply. A mother who is severely deficient in vitamin D, B12, or B6 can pass that deficit to her child, sometimes with devastating consequences.

The B12 case mentioned earlier, where an infant’s seizures traced back to the mother’s undiagnosed pernicious anemia, is a good example.⁹ With vitamin D, infants whose mothers had very low levels showed mean blood concentrations around 5 ng/mL, well below the deficiency threshold, and these infants were the ones presenting with hypocalcemic seizures.⁵ Cultural factors play a role: populations with limited sun exposure, restrictive diets, or clothing that limits skin exposure to sunlight tend to have higher rates of maternal vitamin D deficiency and, consequently, more neonatal seizures from this cause.⁶

For vegan or vegetarian mothers, B12 is the critical concern, since the vitamin is found naturally only in animal products. Without supplementation, a vegan mother’s B12 stores can become depleted during pregnancy and breastfeeding, putting the infant at risk. These babies may appear healthy at birth but develop seizures and regression months later as their reserves run out.

Anti-Seizure Medications That Deplete Vitamins

There is an ironic twist in the relationship between vitamins and seizures: some of the medications used to treat epilepsy actively deplete certain vitamins, potentially making the problem worse over time. This is best documented with folate and B12.

Drugs like carbamazepine and phenytoin lower folate through multiple routes. They interfere with folate absorption in the gut, compete with folate for receptor binding on intestinal cells, slow down folate-metabolizing enzymes, and speed up folate breakdown in the liver.¹⁸ The result is that people who take these medications long-term can develop folate deficiency as a side effect of treatment. A systematic review confirmed this bidirectional relationship: epilepsy leads to nutritional deficiencies through medication effects and dietary changes, while malnutrition itself can be a risk factor for further seizure activity.¹⁹

This is why neurologists who manage epilepsy long-term often monitor vitamin levels and recommend supplementation. It is not just a feel-good wellness measure; it addresses a known pharmacological side effect that could theoretically undermine seizure control.

Adults at Higher Risk

While the most dramatic examples of vitamin-related seizures involve infants, certain adult populations face elevated risk. People with eating disorders are vulnerable because severe caloric restriction depletes multiple vitamins simultaneously, and the electrolyte disturbances that accompany malnutrition (especially low magnesium) compound the seizure risk. The interplay between Wernicke’s encephalopathy from thiamine depletion and other malnutrition-related metabolic problems in this group is still being studied.²⁰

Bariatric surgery patients represent another high-risk group. After procedures that alter the digestive tract, absorption of B12, folate, thiamine, and fat-soluble vitamins like D and E can drop significantly. New-onset seizures after bariatric surgery have been documented and are typically linked to metabolic disturbances including electrolyte abnormalities, though they generally resolve once the underlying cause is addressed.²¹ Chronic alcoholism is a well-known risk factor for thiamine depletion, and people with inflammatory bowel disease, celiac disease, or other malabsorption conditions are vulnerable to multiple deficiencies at once.

Genetic Versus Acquired Deficiency

An important distinction that does not always make it into popular discussions is the difference between a straightforward dietary deficiency and a genetic problem with how the body handles a vitamin. Both can cause seizures, but they look quite different clinically.

Dietary deficiency develops gradually and usually responds well to supplementation at normal doses. You eat more of the vitamin, or take a supplement, and the problem resolves. Genetic conditions, like pyridoxine-dependent epilepsy or cerebral folate transport deficiency, involve mutations that break some part of the vitamin’s metabolic pathway. In these cases, the person may need much higher doses than normal, or a specific form of the vitamin that bypasses the broken step, and they typically need lifelong treatment.

A review of vitamin metabolism-related epilepsy noted that impaired metabolism of thiamine, biotin, B6, B12, and folic acid can all contribute to early-onset seizures and developmental problems in infants, but that timely supplementation can significantly improve outcomes.²² The word “timely” is doing heavy lifting there. For genetic conditions in particular, the window for preventing irreversible brain damage is narrow. Months of untreated seizures in infancy can cause structural changes that supplementation started later cannot undo.

The 1950s Infant Formula Crisis

The connection between B6 and seizures was first recognized not through deliberate research but through an accidental natural experiment. In 1952 and early 1953, a wave of unexplained seizures swept through infants across the United States. The babies had no other signs of illness, no abnormal physical findings, and no laboratory results pointing to a cause. Reports came in from Texas, then Arkansas and California, and eventually from all parts of the country.²³

The common thread turned out to be a specific brand of infant formula that had been processed in a way that destroyed most of its B6 content. Once the connection was identified and the formula was corrected, the epidemic stopped. This episode was a landmark in pediatric nutrition because it provided the first clear proof in humans that B6 deficiency alone could cause seizures. It also shaped modern formula manufacturing standards, which now specify minimum B6 levels to prevent recurrence.

Vitamins as Adjunctive Treatment for Epilepsy

Beyond the question of whether deficiency causes seizures, researchers have explored whether vitamin supplementation might help manage epilepsy even in people who are not technically deficient. The evidence here is more preliminary but growing. A review examining the relationship between vitamins and epilepsy from multiple biological angles found substantial evidence that supplementation could contribute to both treatment and prevention, with particular attention to vitamins D and E.²⁴ The proposed mechanisms include reducing inflammation, protecting against oxidative damage to neurons, and modulating the excitability of nerve cells.

This does not mean people with epilepsy should megadose vitamins hoping for a cure. Vitamin supplementation for epilepsy remains an area of active research, not established clinical practice. But for anyone on long-term anti-seizure medications, ensuring adequate vitamin levels is a reasonable and evidence-supported step, one that addresses both the medication-related depletion mentioned earlier and the possible adjunctive benefits of adequate nutrient status.