Epilepsy.com previously has reviewed the subject of complementary/alternative medicines and vitamins with respect to epilepsy (read more). A recent review article by Lee and Chung in Epilepsy & Behavior 2010, volume 18, pages 139-50, has critically examined the scientific evidence about selected supplements.

• Vitamin E: Several controlled studies pointed to a beneficial effect of 250-400 IU (international units) of vitamin E, but some studies showed no benefit.  Doses of Vitamin E above 400 IU per day can cause severe side effects, such as heart failure, excessive blood clotting and decreased immunity. 
• Fish Oils: Fish oils are rich in omega-3-polyunsaturated fatty acids.  One controlled study showed mild benefit, but others did not.
• Magnesium: Treatment with magnesium sulfate is documented to help control seizures due to the condition called eclampsia (toxemia) of pregnancy.  It is also of value for seizures in people whose magnesium levels are low.  Benefit has not been proven for ordinary seizures.
• Folic acid: Folic acid is useful to prevent certain birth defects in pregnant women. Several studies have shown no benefit of folic acid for seizure control.
• Melatonin: Melatonin is the brain’s natural sleep hormone. Studies of melatonin 1-5 mg per night showed possible benefit, but one study showed worsening, and no study has yet been done using a placebo control group or large numbers of patients. Benefits might relate to increasing sleep, which can help some to reduce their seizures.
• Selenium: Selenium is a trace metal whose deficiency can lead to seizures. Some people with epilepsy have low selenium levels. A few case reports have suggested that daily selenium supplementation in the range of 3-5 mg/kg (recommended daily intake is 55 mg per day) can reduce seizures.  But no scientific study has yet evaluated benefit of selenium for seizure control in people who are not deficient in selenium.

Complementary medicines and supplements are still medicines, and should be used with caution. Being “natural’ does not mean being free from the possibility of producing side effects.  A decision to take any medicine should be based on effectiveness and safety, which can only be evaluated by careful scientific studies.