There are limitations with most of the research studies into the use of vitamin B6 and magnesium supplements for individuals on the autism spectrum that we have identified to date.
Pfeiffer, S.L. et al. carried out a review of the existing research studies into vitamin B6 and magnesium in 1995. They reported that
“The majority of studies report a favorable response to vitamin treatment. However, interpretation of these positive findings needs to be tempered because of methodological shortcomings inherent in many of the studies. For example, a number of studies employed imprecise outcome measures, were based on small samples and possible repeat use of the same subjects in more than one study, did not adjust for regression effects in measuring improvement, and omitted collecting long-term follow-up data.”
Nye and Brice also carried out a review of the existing research studies into the same intervention for the Cochrane Library in 2005. They reported that
“Only three studies met the inclusion criteria of this review and of these only one study reported adequate data for analysis. Results were inconclusive and sample sizes were small. Therefore, the use of vitamin B6 for improving the behaviour of individuals with autism cannot currently be supported.”
Murza et al also carried out a review of the existing research studies into the same intervention in 2010. They concluded that
“Taken as a whole, the research reported since 2005 support the original conclusions of Nye and Brice, ‘Due to the small number of studies, the methodological quality of studies, and small sample sizes, no recommendation can be advanced based on this review regarding the use of B6-Mg as a treatment for autism. There is simply not sufficient evidence to demonstrate treatment efficacy’.”
For a comprehensive list of potential flaws in research studies, please see ‘Why some autism research studies are flawed’