The culprit, it turned out, was raw bok choy. The patient had been eating two to three pounds of it every day for several months, in the belief it would help control her diabetes. Instead, the vegetables may have suppressed her thyroid, according to NYU physicians who described the case in a letter in the May 20 issue of The New England Journal of Medicine. Bok choy contains compounds called glucosinolates that have been found to inhibit thyroid function in animals.
“I don’t want to say people shouldn’t be eating raw vegetables, but everything in moderation — even things that are good for us,” said Dr. Michael Chu, an NYU resident physician who was one of the letter’s authors. “This probably wouldn’t have happened if the vegetables were cooked.”