This article reports that children with autism have much higher levels of vitamin B6 in their blood than children who do not have autism, suggesting that children with autism may have difficulty breaking down B6 into its active form, PLP.
According to some studies, the behavior of children with autism can be improved by vitamin B6. In this study, the authors set out to test whether children with autism metabolize vitamin B6 differently from children without autism. They compared the blood levels of vitamin B6 in 35 children with autism (3-9 years old) with those of 11 controls (6-9 years old). They found that children with autism had significantly higher levels of B6 in their blood. The authors discuss how this result is consistent with previous research showing that the enzyme used to break down vitamin B6 is less active in children with autism. They conclude that supplementation with vitamin B6 may help children with autism because even more B6 would be available to be broken down into PLP.