FRIDAY, June 5, 2015 (HealthDay News) -- Well-intentioned parents of children with autism may think that special diets or supplements can help their child, but a new study suggests that often these efforts lead to problems.
As the researchers explain, many children with an autism spectrum disorder (ASD) are picky eaters, and parents may direct them to nutritional supplements, or gluten- or casein-free diets.
However, the study reported June 4 in the Journal of the Academy of Nutrition and Dietetics found that these regimens leave children still deficient in some nutrients, such as calcium. On the other hand, special diets and supplements can cause children to take in excessive amounts of other nutrients, such as vitamin A, the researchers said.
"Each patient needs to be individually assessed for potential nutritional deficiencies or excess," study lead researcher Patricia Stewart, assistant professor of pediatrics at the University of Rochester Medical Center in Rochester, N.Y., said in a journal news release.
One other expert agreed.
"Children with an autism spectrum disorder are not very different nutritionally from non-ASD children," said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at the Cohen Children's Medical Center of New York, in New Hyde Park, N.Y.
"Giving children with an autism spectrum disorder a multivitamin/mineral supplement will not correct many of the nutritional deficiencies seen in these children," he added, "and may in fact lead to excess amounts of some nutrients in the bloodstream."
The new study involved 368 children aged 2 to 11 years who were treated at five different Autism Speaks specialty centers. Autism Speaks is a nonprofit organization that sponsors autism research and conducts awareness and outreach activities.
The study participants had all been diagnosed with autism, Asperger's syndrome or another so-called "pervasive developmental disorder." The children's caregivers kept a three-day food diary, which recorded the amounts of food the kids ate as well as the drinks and supplements they took.
After analyzing the children's food diaries, the researchers found the kids with an ASD were consuming amounts of nutrients that were similar to other children who did not have autism. They also had the same deficiencies often seen in the general population.
In addition, even among those who took supplements, up to 55 percent of the children with an ASD remained deficient in calcium, while up to 40 percent didn't get enough vitamin D, the study found.
The kids on the gluten-free and casein-free diet ate more magnesium and vitamin E, but they were still deficient in calcium, Stewart's team found.
Much of these special diets and supplements are unnecessary, the authors said, because even children with picky eating habits still get most of their essential nutrients from the food they eat. That's because many of today's foods are fortified with essential vitamins and minerals, the researchers explained.
And, the study authors suggested, that could explain why some kids with autism are getting too much of certain nutrients, such as vitamin A, folic acid and zinc.
"Few children with ASD need most of the micronutrients they are commonly given as multivitamins, which often leads to excess intake that may place children at risk for adverse effects," Stewart said. "When supplements are used, careful attention should be given to adequacy of vitamin D and calcium intake," she added.
Adesman pointed out that some parents with a child with autism may believe that nutrition is somehow key to their child's symptoms.
"Although this study identified nutritional deficiencies and excesses in some children with ASD, this study was not specifically trying to link the nutritional status of these children as a cause for their autism spectrum disorder," he said.
Autism is a neurobehavioral disorder that is now estimated to affect about one in 68 American children, according to the U.S. Centers for Disease Control and Prevention.
Autism Speaks provides more information on complementary treatment approaches for autism.