In this week's "What's Ailing You," a viewer in Fairfield wants to know how to build muscle.

New Canaan author and nutritionist Jill Castle says protein shakes can pack various benefits and risks. She says they can help feed your muscles and curb your appetite because protein has been proven to make you feel full and satisfied for hours.

Castle recommends limiting protein shake intake to one a day. She says they pack so much protein and vitamins that you can overload your kidneys, and they can work against you if you are trying to lose weight.

"Most Americans get enough (protein). If we get too much, if we're not burning it with exercise, we're just storing it as fat and that translates to weight gain," says Castle.

Castle says in some cases, protein shakes contain ingredients that we shouldn't be ingesting. Testing has found lead, arsenic and mercury in some products.

News 12 Connecticut wants to know "What's Ailing You." You ask the medical question and we'll work to find you an expert's answer. Send your questions by way of Facebook or Twitter using the hashtag #WhatsAilingYou.