Variety of food or lack of puts autistic kids at risk for poor nutrition

May 4 2009

The strong preference kids with autism have for certain foods places them at risk for nutritional deficiencies because their diets lack sufficient variety, according to research from Cincinnati Children's Hospital Medical Center at this year's Pediatric Academic Societies meeting in Baltimore.

Presenting their findings May 4, the researchers said screening children for the amount of variety of food in their diets may be a good clinical marker to predict which children might be at risk for nutrition problems. Kids with low food variety scores who are at risk could then be referred to dieticians or therapists to help them expand food choices and improve nutrition, said Michelle Zimmer, M.D., lead investigator and a pediatrician in the division of Developmental and Behavioral Pediatrics at Cincinnati Children's.

The study is one of two presented by Dr. Zimmer and colleagues this year at PAS that deal with autism, the second one showing that the red blood cells of children with autism have low levels of a fatty acid linked to cognitive function. This finding, the researchers report, warrants further research into how the low fatty acid levels may trigger biochemical changes in the brain linked to autism.

The team found that levels of docosahexanoic acid and total omega-3 fatty acids were significantly lower in the red blood cells of autistic children than in normally developing children. Omega-3 fatty acids are nutritionally important substances considered vital to the normal development of children.

Evidence of abnormal fatty acid metabolism in children with autism runs counter to at least one previous study that suggested no difference between normally developing and autistic children. The different results between studies may be explained by the current research focusing on an older group of children, Dr. Zimmer said.

"The fatty acid docosahexanoic is linked to other mental health issues, and this raises questions about whether there are functional issues in neural cells involving a deficiency of essential fatty acids," said Dr. Zimmer. "The main point of the study is we cannot rule that fatty acids are part of the story of what is going on with kids who have autism."

Dr. Zimmer said its possible older children with autism have had more time to use up their bodies' stores of omega-3 fatty acids and are unable to replenish those stores. The 21 children with autism in this study were between the ages of 3 and 18 years, as were the 20 age-matched normally developing children and 10 if their siblings who served as control subjects.

The research team is conducting a larger study with more children to verify its PAS findings. Dr. Zimmer said another study is also under design to give essential omega-3 fatty acids, such as docosahexanonic acid, to children with autism to see what impact it has on brain chemistry and/or the disorder.

Increasing foods rich in omega-3 fatty acids in the diets of autistic children has been suggested by some researchers as potentially beneficial, Dr. Zimmer said. Although doing so would not have a negative impact on the children, until studies are conducted it isn't known what affect, if any, it might have, she added. Also, given the findings of the previous study on the lack of food variety among kids with autism, augmenting their diets could be challenging.

Most of the 19 autistic children in the food study had much lower food variety scores in their diets than typically developing children. A majority of the children with autism also suffered from nutritional deficiencies. The researchers concluded children with autism and low food variety scores are at risk for mild and serious nutritional deficiencies.

Researchers participating in studies were from the division of Developmental and Behavioral Pediatrics and division of Neurology at Cincinnati Children's. Researchers from the department of Pathology at the University of Cincinnati participated in the study on food variety.

The PAS meeting is the largest international meeting focused on research in child health. It is sponsored by the American Academy of Pediatrics, the American Pediatric Society, the Society for Pediatric Research, and the Ambulatory Pediatric Association.