Impact of vitamin deficiency on microbiota composition and immunomodulation: relevance to autistic spectrum disorders.

OBJECTIVES: Inappropriate vitamin supply is a public health problem and is related to abnormalities in brain development, immune response and, more recently, in changes of gut microbial composition. It is known that low levels of vitamin in early life are linked to increased susceptibility to neurodevelopmental disorders, such as Autism Spectrum Disorders (ASD). Unfortunately, the possible peripheral influences of vitamin deficiency that leads to alterations in the gut microbiota-immune-brain axis, one important modulator of the ASD pathology, remain unclear. This narrative review discusses how the impact of vitamin deficiency results in changes in the immune regulation and in the gut microbiota composition, trying to understand how these changes may contribute for the development and severity of ASD. METHODS: The papers were selected using Pubmed and other databases. This review discusses the following topics: (1) vitamin deficiency in alterations of central nervous system in autism, (2) the impact of low levels of vitamins in immunomodulation and how it can favor imbalance in gut microbiota composition and gastrointestinal (GI) disturbances, (3) gut microbiota imbalance/inflammation associated with the ASD pathophysiology, and (4) possible evidences of the role of vitamin deficiency in dysfunctional gut microbiota-immune-brain axis in ASD. RESULTS: Studies indicate that hypovitaminosis A, B12, D, and K have been co-related with the ASD neuropathology. Furthermore, it was shown that low levels of these vitamins favor the Th1/Th17 environment in the gut, as well as the growth of enteropathogens linked to GI disorders. DISCUSSION: GI disorders and alterations in the gut microbiota-immune-brain axis seems to be linked with ASD severity. Although unclear, hypovitaminosis appears to regulate peripherally the ASD pathophysiology by modulating the gut microbiota-immune-brain axis, however, more research is still necessary to confirm this hypothesis.

[Colon lactoflora of rats with alimentary polyhypovitaminosis and modified fat component of diet].

The examination was carried out on male Wistar rats with an initial weight 97-121 g. Influence of vitamin provision and composition of fat component in semisynthetic diet on the condition of lactoflora population of intestine were studied. The deficiency of vitamins was caused by fivefold decrease of amount of vitamin mixture added to the feed and by elimination of vitamin E from this mixture. The modification of fat component was made by substitution of sunflower oil for linseed oil in equal amount (the ratio of vegetable oil and animal fat (lard) was 1:1). Duration of the first phase of the experiment was 28 days. Vitamin deficiency in rats, receiving feed with sunflower oil, was accompanied by significant decrease of vitamins A, E, B1 and B2 in the liver, but did not affect the quantity of lactobacilli in caecum content of rats. Enrichment of the diet deficient in vitamins with polyunsaturated omega 3 fatty acids was associated with a statistically significant increase in number of lactobacilli in the intestine compared with the control group (9.78+/-0.08 opposite 8.82+/-0.33 Ig CFU/g, p=0.018) and group of rats with vitamin deficiency (9.03+/-0.18 Ig CFU/g p = 0.006). On the second stage, replenishment of vitamin deficiency was carried out in the next 14 days by increasing the amount of vitamin mixture to 70 and 200% of vitamin content from a diet in control group. The replenishment has not affected the number of caecum lactobacilli irrespectively of the dose of vitamins and fatty component.

Helicobacter pylori and micronutrients.

Helicobacter pylori (HP) infection causes morbidity in several systems, especially in the gastrointestinal tract. The prevalence of disease is inversely related to social-economic and developmental status. It is more common in the developing than in developed countries. In the countries where social-economic status is low, not only HP infection, but also malnutrition and growth failure have a higher prevalence. According to these data, the relationship of nutrition and HP infection is still a question. Does HP infection affect nutritional status? On the contrary, does nutritional status affect HP infection? If so, how? This review was prepared after searching thoroughly almost all of the publications about relationship between HP infections and micronutrients, especially publications pertaining to childhood, from 1990 to 2009 in PubMed. Some valuable adult and experimental publications were also reviewed. These studies related H. pylori to iron, vitamin B12, vitamin C, vitamin A, vitamin E, folate, and selenium. Published studies reveal some evidence that HP has a negative effect on iron, vitamin B12 and vitamin C metabolism, but its influence on others is not clear.