The Role of Vitamins in Autism Spectrum Disorder: What Do We Know?

Vitamin or mineral supplementation is considered to be the most commonly used medical treatment for autism spectrum disorder (ASD), in addition to other interventions such as neurological and psychological interventions. There is not much evidence of therapeutic efficacy between vitamin and mineral supplementation and improvements in ASD. However, several researchers have noted that patients with ASD have various metabolic and nutritional abnormalities including issues with sulfation, methylation, glutathione redox imbalances, oxidative stress, and mitochondrial dysfunction. There is some evidence that vitamin and mineral supplementation may support these basic physiologic processes. Recently, the nutritional status of ASD patients has been gaining focus in this particular area. Pointing out the nutritional status as a potential etiological factor for attention/communication disorders, more importance has been given to this particular point. Moreover, autistic specific considerations like the feature and behavior of ASD might be increased or at least fall in the higher risk due to the sub-optimal nutritional status.

Tryptophan status in autism spectrum disorder and the influence of supplementation on its level.

Recent reports show that the worldwide incidence of autism spectrum disorder (ASD) is dramatically increasing, although ASD etiology and pathogenesis are still far to be fully elucidated. Some dietary-derived essential compounds, such as the amino acid tryptophan, appear to be impaired in patients with ASD. Tryptophan (Trp) plays a significant role in the human organism and serves as a precursor for a wide range of bioactive compounds, including major neurotransmitters. Research indicates that tryptophan might be deficient in subjects with ASD. Deficiency in the tryptophan level can be retrieved by investigating Trp levels or its major metabolite kynurenine in urines. The purpose of the present study is to quantify tryptophan content in urine samples (n = 236) of ASD patients, who underwent a supplemented dietary panel with B vitamins and magnesium, compared to controls (without this diet regimen). The samples were analyzed with gas chromatography-mass spectrometry. Additionally, the correlation between body mass index (BMI) and the level of this amino acid in urine was accomplished. Basic parameters of urine samples were also evaluated. Statistical evaluations in the concentration of tryptophan in ASD patients with different severity of symptoms were reported. A significant difference in tryptophan levels in all groups was observed. Supplementation with B vitamins and magnesium has an influence on the Trp concentration. Furthermore, no correlation between BMI and tryptophan levels was found. These results assess that the Trp level in ASD subjects is critical and that intake of B vitamins and magnesium with diet might influence its metabolic homeostasis.

Chromatographic determination of harmalans in the urine of autistic children.

This paper presents a new approach to autism - a complex and still enigmatic condition. We present the results of our preliminary research which was based on the detection of the hallucinogenic substance 6- (or 10-)methoxyharmalan in the urine samples of autistic children with the use of chromatographic methods. Additionally, we aim to describe the relationship between the level of tryptophan and harmalan, and the influence of supplementation on the level of this compound. We applied HPLC-UV/vis, HPLC-DAD and LC-MS in order to determine McIsaac's compound in the urine samples obtained from autistic children (n = 132) and healthy individuals (n = 10). The level of tryptophan was quantified with the use of GC-MS. Our research shows the presence of the McIsaac's compound in 110 samples of ASD children contrary to healthy children, where it was not found. No relationship between the level of tryptophan and 6-methoxyharmalan was noticed. The study shows a strong influence of melatonin supplementation on the presence of the McIsaac's compound. We believe that the results of our research can contribute to a better understanding of autism spectrum disorders. Moreover, our findings can form the basis for other studies focused on autism, eventually making it possible to understand its etiology.