Study On The Association Between Vitamin A Nutritional Status And Structure Of Gut Microbiota In Children With Autism Spectrum Disorder

Objective: This study aimed to investigate dietary and blood vitamin A nutritional status and its influencing factors in children with autism spectrum disorder,analysis the association between vitamin A and the structure of gut microbiota,and determine specific bacteria associated with vitamin A.Methods: This cross-sectional study was conducted in six special education institutions in Changsha city,Hunan Province,from October2020 to October 2021.A total of 160 children with ASD were enrolled.Basic information of children and their families was collected by electronic questionnaire,severity of ASD symptoms was assessed by Social Response Scale,food intake frequency and nutrient intake of various foods were assessed by food frequency questionnaire and 3-day food diary,respectively.Fasting venous blood was collected for vitamin A and vitamin D concentration,feces were collected for 16 s high-throughput sequencing analysis of gut microbiota characteristics.Results :(1)Inadequate vitamin A intake accounted for 41.2% of children with ASD.Only 40.0% of children with ASD took adequate vitamin A-rich fruits and vegetables(≥7 times/week),30.0% of children with ASD took adequate animal liver(≥1 time/month).Children in the larger age group were more likely to have inadequate vitamin A intake than those in the younger age group(OR = 15.775,95% CI:2.862～86.960,P = 0.002),low frequency of vitamin A-rich fruits and vegetables intake was a risk factor for insufficient vitamin A intake(OR =3.343,95% CI: 1.125～9.931,P = 0.03).(2)Vitamin A deficiency(including marginal deficiency)was found in 30.9% of children with ASD.There was A significant positive correlation between vitamin A supplementation and vitamin A level(P =0.013).(3)Environmental factor analysis of intestinal flora showed that,in basic factors,gestational age and severity of ASD symptoms contributed the most to the structural variation of intestinal flora in children with ASD;in food frequency,refined grains,processed meats and vitamin A-rich fruits and vegetables made the biggest contribution.In nutrient intake,fat and carbohydrate contributed the most;Among the blood biochemical indexes,vitamin A contributed the most.(4)There was a significant negative correlation between frequency of vitamin A-rich fruits and vegetables intake and Simpson among ASD children(P < 0.05).The relative abundance of Christensenellaceae was higher in children with inadequate intake of vitamin A-rich fruits and vegetables than in children with adequate intake(P < 0.05).Compared with children with adequate animal liver intake of ASD,the relative abundance of Clostridium was higher in children with inadequate intake(P < 0.05).Compared with ASD children with adequate vitamin A intake,children with inadequate vitamin A intake had lower relative abundance of Blautia and Lachnospiraceae(P < 0.05).(5)There was a significant negative correlation between ASD serum vitamin A level and Chao1(P < 0.05).Compared with ASD children with vitamin A adequacy,the relative abundance of Veillonella and Barnesiellaceae were higher in children with vitamin A inadequacy(P <0.05).Conclusion: The deficiency of vitamin A intake accounted for a high proportion in children with ASD.Dietary and serum vitamin A levels were associated with lower intestinal microbial diversity and increasing beneficial bacteria and decreasing harmful bacteria colonization.Our study suggests that vitamin A may affect the severity of ASD through gut microbiota.