For Brandon Greaves, a gluten- and casein-free (GFCF) diet improved his gastrointestinal and behavioral symptoms and even led to increased language and social function. Nixing soy — another common problem food — helped, too. Kenneth Bock, MD, a family practice doctor in Rhinebeck, New York, and author of Healing the New Childhood Epidemics (Ballantine, 2007), says that although no dietary treatment works for every child, he cuts out gluten and casein for nearly all of his ADHD and autistic patients, for at least a period of time. The GFCF diet “turns lives around,” Bock says. But, despite rising popularity among parents and doctors, the GFCF diet remains controversial.

Current anecdotal evidence suggests that elimination diets may help a surprising number of these kids. “Two-thirds of autistic children and around half of children with ADHD will benefit from a gluten- and casein-free diet,” Laake says. But other experts say better research on the subject is needed. The few studies published to date each had design flaws and results contradict one another. Stay tuned, however: The results from a randomized, double-blind, placebo-controlled study sponsored by the National Institute of Mental Health are expected out this year.

Laake advises an “elimination and challenge” approach, where one food is removed at a time and the child is monitored for symptoms. If no improvement is seen within one month, the food is reintroduced. “The best test is the child's own body,” Laake says. Because gluten and casein are among the most common intolerances, Laake recommends eliminating foods that contain these first, followed by soy, corn, yeast, and other commonly reactive foods, if necessary.