How can you avoid having too much iron? (Scientific update: a review of recent scientific papers related to vegetarianism).

Iron deficiency is certainly a health problem. Too much stored iron can also be problematic; it has been tentatively associated with heart disease, cancer, and diabetes. Generally, iron stores, as measured by serum ferritin, increase with age until about the sixth decade when they level off. A large study of elderly Americans found that close to 13% had high iron stores, suggesting that iron absorption was not reduced when iron stores were high, as is usually the case. Researchers examined the diets of these individuals to find out if dietary factors or supplement use contributed to the risk of having high stores of iron. They found that those subjects who took more than 30 milligrams daily of iron supplements tended to have high iron stores. Eating more than four servings of red meat per week also increased the risk of having high iron stores, as did eating fewer than seven servings of whole grains per week. Vitamin C, found in fruit, increases iron absorption, so eating more than 21 servings of fruit a week, along with the other previously mentioned factors, also increased risk of elevated iron stores. These findings suggest that older Americans should limit the amount of red meat that they eat, eat more whole grains, and avoid high-dose iron supplements unless prescribed by a health care professional.

Fleming DJ, Tucker KL, Jacques PF, et al. 2002. Dietary factors associated with the risk of high iron stores in the elderly Framingham Heart Study cohort. Am J Clin Nutr 76:1375-84.