Ask the Dietitian
By Althea Zanecosky, MS, RD, LDN
Mid-Atlantic Dairy Association
March 2010
Q: There’s been lots of questions as to what causes autism. I’ve heard that dairy foods can cause or aggravate autism in children. Is there any scientific research about this?
A: According to the Autism Society of America, more than 500,000 Americans have some form of autism. This developmental disability typically appears during the first three years of life and is characterized by problems interacting and communicating with others. Many individuals exhibit repeated body movements such as hand-flapping or rocking and may resist changes in routine. In some cases, they may display aggressive or self-injurious behavior.
There is no known single cause for autism, but it is generally accepted that it is caused by abnormalities in brain structure or function. Brain scans show differences in the shape and structure of the brain in autistic versus non-autistic children. Researchers are investigating a number of theories, including the link between heredity, genetics and medical problems. Studies exploring a dietary link to autism have been less than convincing, and the notion has not generally been accepted by experts in the field.
Two University of Florida animal studies investigated the connection between autism and an individual's inability to properly break down a protein found in milk. The researchers found that when not completely digested, a certain milk protein produces a compound called exorphins. Exorphins can be taken up by areas of the brain known to be involved in autism where they cause cells to dysfunction. These animal findings suggested that a digestive flaw, such as a malfunctioning enzyme in the intestine, could be where the trouble lies.
Whether there is any scientific basis to the animal claims is being put to the test in humans. Children's Hospital of Pittsburgh is looking into parents that were saying anecdotally that food changes could be helpful with their child’s autism. While the Pittsburgh researchers say there is no concrete biological evidence to show diets have any impact on children with autism, they are investigating the effectiveness of three alternative diet therapies in the treatment of autism: use of a supplement known as omega-3 fatty acid (the healthy oil found in some fish and flaxseed); a diet free of wheat and milk protein; and a diet that restricts sugar. Studies at the University of Rochester Medical Center are examining the effects that a gluten- and casein-free diet may have on children with autism.
Scientists say it is likely that both genetics and environment play a role in autism and that there currently is no cure. The National Institute of Neurological Disorders and Stroke (NINDS) states “There are a number of controversial therapies or interventions available for autistic children, but few, if any, are supported by scientific studies. Parents should use caution before adopting any of these treatments.” Current studies do not provide sufficient evidence of any causal relationship of dairy foods and autism and do not support changing advice on the consumption of milk. For more information about autism, the following Web sites may be helpful:
National Institute of Mental Health at http://www.nimh.nih.gov/publicat/autism.cfm
Autism Society of America at http://www.autism-society.org