Iron is a vital nutrient, and the high levels contained in meat-rich Western diets have long been presumed safe. But Sullivan has identified several trends suggesting that the dangers of “normal” iron levels may dwarf those of high cholesterol. For example, women’s cholesterol levels change little after menopause, yet their iron levels rise sharply, and so do their heart-attack rates. Experts have traditionally blamed hormonal changes for the sudden surge in cardiovascular illness. But Sullivan challenged that notion in a landmark 1981 article. Drawing on data from the nation’s largest risk-factor survey, he showed that surgical removal of the uterus (the site of menstrual bleeding) causes an increase in heart-attack risk even if the ovaries are left to produce estrogen. The implication seemed obvious: without menstrual bleeding, the body retains more iron, and that iron somehow damages the cardiovascular system.
Sullivan’s proposal met a wall of silence, but he kept finding new uses for it. Unlike mainstream thinking, the iron hypothesis accounted logically for the fact that young women with a genetic disorder causing extremely high cholesterol rarely suffer any consequences until after menopause. It also helped explain the enigma of Seventh-day Adventist men, who experience only half as many heart attacks as one would expect to see among nonsmokers with average cholesterol counts. Seventh-day Adventists eat eggs and dairy products freely, but their diet is devoid of iron-rich meats. Most important, the iron hypothesis made sense of puzzling global disease patterns. In a 1989 study, Harvard chemist Randall Lauffer showed that while a country’s average cholesterol reading may not correspond directly to its heart-attack rate, its combined cholesterol-and-iron count usually does.
What the iron theorists lacked, until last week, was a controlled study showing what happens to otherwise similar people who have different iron levels. From 1984 through 1989, Dr. Jukka Salonen and his colleagues at the University of Kuopio plotted heart-attack rates against iron levels and 18 other risk factors in 1,931 men from eastern Finland. The results were astounding. Taken by itself, the level of so-called bad cholesterol (LDL) in a man’s blood didn’t significantly affect his heart-attack risk. The level of ferritin (the protein that houses iron in the bloodstream) affected it dramatically: every 1 percent variation in ferritin brought a 4 percent difference in risk. Heart attacks were twice as common in men with ferritin counts over 200 than in those with lower readings. And men with both high iron and high cholesterol were fully four times as likely to be stricken.
Arresting as they are, the Finnish findings don’t close the case against iron. Even if iron is the villain it appears to be, no one yet knows whether lowering people’s iron levels will prevent heart attacks. But finding out should be easy. By giving up three units of blood each year, the average man could achieve the iron status of a premenopausal woman. To gauge the effects of that regimen, a researcher would need only to follow a large group of regular blood donors for several years, comparing their heartattack rates with those of qualified nondonors. Sullivan proposed just such a study 11 years ago, when he first floated his hypothesis. In light of the new evidence, perhaps he or someone else will finally get the support to carry it out.
Should we be changing our lives in the meantime? Dr. Basil Rifkind, a cardiovascular expert at the National Heart, Lung and Blood Institute, favors holding out for stronger evidence. “I don’t think we can advise the public on the basis of a single study,” he says. But others think modest precautions are already in order. Knowing your iron level can’t hurt; large diagnostic labs now offer iron readings as part of a basic blood workup. And unless you have a serious deficiency, iron supplements are not a good idea. Avoiding meat (especially liver) and fortified cereals may be prudent as well. No one can yet say that becoming a regular blood donor will save your life, but it’s harmless-and it may help save someone else.
