A helping of turkey

IT’S a Thanksgiving Day ritual -- lolling around after dinner complaining that the turkey has made you sleepy. This myth (yes, it’s a myth) emerges from the fact that turkey contains the amino acid tryptophan, which can play a role in sleep.

But to have this effect, tryptophan must be taken on an empty stomach -- and in much higher doses than one can consume in food. It may, however, have another effect. A new study suggests this natural substance may have an effect on the immune system.

Stanford University scientist Lawrence Steinman and his research group recently discovered that in an animal model, a metabolite of tryptophan can soothe an overactive immune system. Diseases such as multiple sclerosis and rheumatoid arthritis are caused by an overactive immune system that attacks the body.

Though there is no evidence that eating lots of turkey or chicken (which may contain more tryptophan) can cure or improve immune system disorders, the research eventually could lead to a medication for such conditions.

“We’re moving very hard and fast to organize a well-controlled clinical trial in the area of multiple sclerosis,” says Steinman, whose study was published this month in the journal Science. “Modulating a diet may be a hard way to do it. But if we can find chemicals that do make a difference, we can develop drugs to get those levels up.”