Vitamins that may be helpful

Uncontrolled and double-blind research shows that vitamin B6 can be helpful for autistic children.^{3 4 5} In these trials, children typically took between 3.5 mg and almost 100 mg of B6 for every 2.2 pounds of body weight, with some researchers recommending 30 mg per 2.2 pounds of body weight. Although toxicity was not reported, such amounts are widely considered to have potential toxicity that can damage the nervous system; these amounts should only be administered by a doctor. One prominent researcher has suggested that vitamin B6 is better supported by research than is drug treatment in dealing with autism.⁶

Some autistic children suffer from chronic diarrhea. In a study of children with autistic spectrum disorders and persistent diarrhea for many years, supplementing with 500 mg of glucosamine per day (spread over the morning and evening meal) for 30 days eliminated the diarrhea in five of six cases.⁷ The authors hypothesized that glucosamine worked by blocking the effect of certain dietary components on the intestinal tract.

In one double-blind trial lasting ten weeks, autistic children given 1 gram vitamin C for each 20 pounds of body weight showed a reduction in symptom severity compared with placebo.⁸ The authors speculate that vitamin C may play a positive role because of its known effects on a hormone pathway typically disturbed in children with autism.

Some researchers have added magnesium to vitamin B6, reporting that taking both nutrients may have better effects than taking B6 alone.⁹ The amount of magnesium—10 to 15 mg per 2.2 pounds of body weight—is high enough to cause diarrhea in some people and should be administered by a doctor. Doctors will often try vitamin B6 or the combination of B6 and magnesium for at least three months to see whether these nutrients help autistic children. In a preliminary trial, one group of researchers found that relatively small daily amounts of magnesium (6 mg per 2.2 pounds of body weight) and vitamin B6 (0.6 mg per 2.2 pounds of body weight) improved symptoms by about 50% in children with autism or a related condition (pervasive developmental disorder).¹⁰