For most women, the issue is getting enough iron. For adult men and postmenopausal women, the problem could be getting too much iron. Since men and older women don't lose iron through monthly periods, even the smallest intake will generally provide their daily needs. One study recently documented the high incidence of elevated iron stores in the elderly (American Journal of Clinical Nutrition, 2001, vol. 73, no. 3). When researchers tested 1,016 white Americans, ages 67 to 96, they found only 1 percent to be iron deficient, whereas 13 percent had excessive iron levels.

A 1980s study of Finnish men linked high iron stores with increased risk of heart attacks. And some experts suspect that elevated iron amounts increase heart disease risk, since rates among women do increase when their monthly periods stop. However, the current data don't prove that high iron levels cause heart disease, according to the National Institutes of Health. "The research is controversial, but err on the side of caution," says Chris Rosenbloom, RD, PhD, associate professor and chair of Georgia State University's department of nutrition, in Atlanta. "I tell men and postmenopausal women to look for multivitamins with minimal amounts of iron, if they use multivitamins at all," Rosenbloom says. Multivitamins labeled as "men's formulas" or "senior formulas" have been created with the minimal iron requirements of these groups in mind. It's best, of course, to check with your doctor before taking any supplement.

Besides these potential long-term results of iron overload, taking too much iron can also cause constipation, vomiting and diarrhea in the short term. For children, an iron overdose is potentially deadly, which is why it's very important to put all prenatal vitamins or iron-containing pills safely out of their reach. It's rare to get toxic levels of iron from food alone, so if you don't have to take supplements, don't. Pass the beans, please.