Ask Tufts Experts

I have fish a few times a week but heard about new guidelines warning against eating fish because of high mercury levels. Should I cut back on my fish intake?

Probably not. The new guidelines apply only if you are a woman who may become or is currently pregnant, a nursing mother, or a young child—mercury can cause neurological damage in unborn babies and young children. Even for these groups, out-and-out “avoid” advice applies only to certain species of fish.

They should not eat any shark, swordfish, king mackerel, or tilefish. As for other types of fish, the government recommends that the vulnerable groups eat up to 12 ounces a week.

Note: Canned white albacore tuna has more mercury than canned light tuna, so only one 6-ounce can of albacore tuna should be consumed in a week by women of childbearing age or children.

You recently wrote that a calcium build-up in the arteries can signal an impending heart attack. Is the build-up the result of too much calcium in the diet?

No. “The calcium that builds up in arteries is independent of the calcium you consume, most of which goes into your bones,” says Alice Lichtenstein, DSc, director of the Cardiovascular Nutrition Laboratory at Tufts. What happens is that deposits of fatty plaque in the arteries contribute to the production of a protein that binds minute amounts of calcium circulating in the blood. Thus, the artery walls become “calcified.”