Q: I found the radiation leaks from Japan’s tsunami-damaged nuclear plants truly frightening. Someone at my health-food store said everyone should start eating more seaweed. How would that help? — Deirdre, San Diego A: We love seaweed as a low-calorie, high-nutrient addition to soups, salads and sandwiches. And many types of seaweed contain alginate, which prevents about 78 percent of radioactive products from being absorbed by your bones and teeth. Seaweed also contains iodine, which takes up residence in your thyroid and keeps any radioactive iodine that’s around from being able to settle there, where it can cause cancer.

But like the potassium iodide tablets that flew off the shelves after Japan’s disaster, seaweed won’t protect you from radiation burns, sickness or cancer elsewhere in your body. Plus, eating large amounts of iodine-laden seaweed every day when you’re in no radiation danger has a downside: It actually can slow or halt healthy thyroid activity.