Conscious Choice: Too Much of a Good Thing

April 2003 | Health Conscious

Too Much of a Good Thing

by Bill Sardi

Studies reveal that blood donors exhibit lower rates of many diseases and experience better than average health. Additionally, the centuries-old practice of bloodletting is being revived as a treatment for disorders such as heart disease, cancer and Alzheimer’s. Why would blood reduction improve health parameters? In part, because blood removal helps to control circulating iron levels.

Iron is an essential component of hemoglobin in red blood cells, is associated with strength, and is required for oxygen transport, DNA synthesis, and other processes. But it also has a destructive nature. In its free form it accelerates oxidation or "rusting" of body tissues. Since iron-induced oxidation worsens the course of virtually every disease, iron control could be a universal approach to disease prevention and therapy.

Whereas poor iron intake, or impaired absorption, may lead to anemia, too much iron — iron overload — is even more problematic. After full growth is achieved, at about age 18 or so, excess iron accumulates in the blood of all humans at the rate of one milligram (mg) per day. Women are less at risk for iron buildup than men because of the blood they lose monthly during menstruation. Their rates for heart disease, cancer, and diabetes are also about half those of males. Because men have no direct outlet for iron, by age 40 their iron levels are similar to those of a postmenopausal 70-year-old woman. This amount of iron can lead to premature aging and diseases such as arthritis, cancer, cataracts, diabetes, osteoporosis, and retinal, liver, and brain disorders. Postmenopausal women, or women who have undergone early hysterectomy in their 20s, 30s and early 40s, may experience similar problems.

Recognizing The Problem

Iron overload hasn’t gone completely unnoticed. There are a number of books on the topic, but most are written for health professionals, leaving the public largely unaware of the problem. The emphasis on preventing anemia in children and menstruating women has detracted attention from progressive iron buildup in adult men and postmenopausal women.

Upon closer inspection, many health-promoting practices inadvertently control iron. For example, taking an aspirin a day to prevent heart attacks and strokes causes blood loss via the digestive tract on the order of about a tablespoon per day. This results in iron loss. By exercising, a person loses about one miligram of iron through sweat. Fasting and vegetarian diets, both of which promote longevity in animals and humans, limit iron consumption because red meat contains the highly absorbable heme iron. Whether or not related to iron consumption, restricting red meat consumption has been shown in various studies to reduce the risk of colon cancer.

In healthy individuals there is little if any unbound iron circulating in the blood. In all disease states, however, unbound iron (also called free iron) is released at sites of inflammation and can spark uncontrolled oxidation. Fortunately, there are numerous automatic mechanisms in the body that help to control iron. This is important because pathogenic organisms such as viruses, bacteria and fungi require iron for growth.

Blood tests for iron levels are often useful, but the results of these tests are confounded in states of prolonged inflammation or disease. A skilled hematologist is often the best professional from whom to obtain personal information concerning blood iron levels.

Humans absorb only a fraction of the iron they consume, but there are many controlling factors. Iron absorption rates from food vary widely, from less than 1 percent to nearly 100 percent. Generally, iron in plant foods is not as well absorbed as iron from meat: Only 5 percent of iron in plant foods is available, vs. 30 to 50 percent of iron from meat.

Vitamin C increases iron absorption. However, there is no evidence that vitamin C leads to iron overload. Thus vitamin C should not be avoided by meat-eaters for this reason, since studies show high-dose vitamin C supplements are associated with a decreased risk for heart disease, cancer, cataracts and other disorders. A vegetarian diet does not generally cause iron-deficiency anemia because there is more vitamin C in plant-food diets, which enhances absorption. Bioflavonoids (found in berries, coffee, green tea, pine bark, quercetin, and the rind of citrus fruits, particularly blueberry, cranberry, elderberry, and grape seed) and phytic acid (a component of whole grains and seeds such as sesame) bind to iron and other minerals in the gastric tract and help to limit iron availability.

For those at risk for iron overload, it may be wise to avoid iron in multivitamins and shun fortified foods that provide more than 25 percent of the recommended daily intake for iron. No doctor should prescribe iron tablets for patients who complain of fatigue without blood tests and a thorough health history. Iron-rich foods such as red meat and molasses may prevent anemia and build strength during the growing years but in adulthood may lead to iron overload among men and postmenopausal women. Those individuals who learn how to achieve iron balance will maintain the most desirable state of health throughout life

Bill Sardi is a health journalist and consumer advocate in Diamond Bar, CA.

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