David L. Katz, MD
Photo: Mackenzie Stroh
Q: I'm a healthy 39-year-old woman, but I seem to be suffering from yeast infections more and more frequently, and I think my diet is to blame. Are there foods that are a definite no-no for me?
— Susan D'Angelo
Cambridge, Ontario

A: Vaginal yeast infections are most often caused by a fungus called Candida albicans. Yeast loves sugar, which may help explain why women who get a lot of it in their diet seem to suffer more infections. Some research suggests that women with recurrent episodes may also have slightly more trouble metabolizing blood sugar—their levels rise a bit higher after a meal. So limiting your intake of simple sugars, white flour, and starchy snacks may be helpful.

You may hear advice about avoiding foods that contain yeast, from bread to beer, but I'm not convinced this is necessary, because the scientific support is so limited.

There is evidence that probiotics—friendly bacteria—can be protective against yeast infections (friendly bacteria crowd out any candida that try to roost there). Acidophilus is the one that seems to help most. You can take it as a supplement—follow the dosing instructions on the package—or get it from a cup of live-culture yogurt daily.