MADISON A University of Wisconsin-Madison researcher has detected a higher rate of seizures among children with autism who were fed infant formula containing soy protein rather than milk protein.
The study found excess seizures among girls and in the total sample of 1,949 children. The soy-seizure link reached borderline significance among boys, who comprised 87 percent of the children described in the database under study.
Seizures caused by uncontrolled electrical currents in the brain occur in many neurological disorders including epilepsy, Alzheimer's disease, Down syndrome and autism.
About 25 percent of infant formula sold in the United States is based on soy protein.
Study author Cara Westmark, a senior scientist in the UW-Madison department of neurology, says her investigation was sparked by mouse studies of a drug that, it was hoped, would inhibit seizures by blocking signals that excite nerve cells. "It was pure serendipity that we happened to look at soy," she says.
To simplify the mouse study, she replaced the standard lab chow, which had a variable composition, with a diet containing purified ingredients. Unexpectedly, that diet reduced the rate of seizures by 50 percent compared to standard chow, Westmark says.
"We were intrigued that a dietary alteration was as effective as many medicines in reducing seizure incidence and wanted to pursue that finding," she says. "We found that the main difference between the diets was the protein source. The standard diet was soy-based, while the purified diet was casein, or dairy, based."
The mechanism of action is unknown, but Westmark points to the high level of plant-derived estrogens in soy products as a possible cause of the excess seizures.
People eat a lot of soy products, and when Westmark began to look for the effect in people, she decided to focus on infants, who may consume nothing but formula. Knowing that people with a
|Contact: Cara Westmark|
University of Wisconsin-Madison