One study found that children with autism had high levels of plasma vitamin B6 pre-supplementation, and this finding was confirmed in a follow-up study, suggesting a metabolic imbalance in B6. Several other studies have also demonstrated increased oxidative stress. One study in Romania found normal levels of vitamin B12 and folate in children with autism compared to controls, but low levels of plasma glutathione. Three studies have demonstrated that children with autism have impaired methylation, decreased glutathione, and oxidative stress, and those studies demonstrated that nutritional supplementation (with vitamin methyl-B12, folinic acid, and trimethylglycine) is beneficial. There have been several studies of the nutritional and metabolic status of children with autism, but each focused on study of only a few biomarkers. We hypothesize that nutritional insufficiency and metabolic imbalances may play a role in autism spectrum disorders (ASD).

More recently the focus has shifted to the relationship between relative metabolic disturbances and developmental disorders, for example those associated with Attention Deficit Disorder, learning disorders, and intellectual development. However, nutritional status depends not only on intake, but also on digestion, absorption, metabolic processing, and metabolic demand. Vitamins, minerals, and essential amino acids are, by definition, essential for human health, primarily due to their critical function as enzymatic cofactors for numerous reactions in the body, such as the production of neurotransmitters and fatty acid metabolism Historically attention has focused on inadequate intake of vitamins and minerals due to poor diet as a major contributing factor to many child health problems in the US and around the world, including anemia (low iron), hypothyroid (low iodine), scurvy (vitamin C deficiency), and rickets (calcium and/or vitamin D deficiency).

Forty-Ninth by Boris Pronsky