In the largest study of its kind, researchers with the Autism Speaks Autism Treatment Network (ATN) found that supplements and special diets for children with autism commonly result in excessive amounts of some nutrients and deficiencies in others. In particular, they found that many of the children in their study were consuming high and potentially unsafe levels of vitamin A, folic acid and zinc while not getting enough calcium and vitamin D.
The study appears this week in the Journal of the Academy of Nutrition and Dietetics. The research was supported through the ATN’s role as the federally funded Autism Intervention Research Network on Physical Health (AIR-P).
“Few children with autism spectrum disorder need most of the micronutrients they are commonly given as multivitamins,” says lead researcher Patricia Stewart, a nutritionist in the Autism Speaks ATN at the University of Rochester Medical Center. “[This] often leads to excess intake that may place children at risk for adverse effects. When supplements are used, careful attention should be given to adequacy of vitamin D and calcium intake.”
The authors encourage families and healthcare providers to individually assess diet and nutrient levels in children with autism who are on restricted diets. Many children with autism tend to be picky, or selective, eaters. And many are on gluten-free/casein-free diets, which eliminate wheat and milk products.
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The study included 368 children, ages 2 to 11 years, diagnosed with autism and being seen at one of five Autism Speaks ATN sites: Cincinnati Children's Hospital, University of Arkansas, University of Colorado, University of Pittsburgh and University of Rochester. Twelve percent of the children were on a gluten-free/casein-free diet. And 78 percent were taking nutritional supplements.
A nutritionist trained the children’s caregivers to keep detailed diaries of all foods, drinks and supplements consumed. This included recipes, brand names and photographs of nutritional supplement labels. The researchers then analyzed three days of food records.
Overall, the investigators found that the children were consuming vitamins and minerals in amounts typical of children without autism. They also had similar deficiencies. Most commonly these involved vitamins D, E, calcium, potassium and choline.
However, many of the children in the study who were taking supplements were getting potentially unsafe amounts of vitamin A, folate and zinc. In addition, overconsumption of vitamin C and copper was common among participants ages 2 to 3, and excess manganese and copper was common for those 4 to 8 years old.
Of particular concern, around half of the children who had autism and were taking supplements were still not getting enough calcium. Around a third were not getting enough vitamin D.
As a group, the children on a gluten-free/casein-free diet got more magnesium and vitamin E than the other children did. This may be due to the substitution of soy and nut-based products for dairy, the researchers note. Children on a gluten-free/casein- this diet were also more likely to be getting enough vitamin D than were the other children.
“Feeding and nutrition are major issues for many children with autism,” comments developmental pediatrician Paul Wang, Autism Speaks’ head of medical research. “This new study shows that both nutritional deficiencies and nutritional excesses are common. We don't know the consequences of all these nutritional imbalances. But some could be important.”
For example, Dr. Wang notes that low calcium intake may contribute to the unusually high rate of bone fractures seen in children with autism.
“Many children and families affected by autism can greatly benefit from the support of nutritionists and feeding specialists to ensure both immediate and long-term health,” Dr. Wang concludes. The 14 medical centers in the Autism Speaks ATN provide such expertise and work actively to help educate healthcare providers and families in their surrounding communities.