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McJunk Science


McDonald's just announced it will use a different cooking oil to reduce the amount of trans fatty acids in its fried foods. It sounds like an advance for corporate responsibility and public health. But it's actually a big fat mistake.

The Food and Drug Administration inexplicably has yearned for the last several years to require information about so-called "trans fats" on food nutrition labels. Support for the FDA's plans came in a report released this summer by the National Academy of Sciences' Institute of Medicine, which concluded that no amount of trans fats is safe to eat.

Trans fats, according to the report, raise blood levels of low-density lipoprotein -- the supposedly "bad" cholesterol -- and increase the risk of coronary heart disease. Because trans-fatty acids are "unavoidable in ordinary diets," the Institute of Medicine "recommended that trans fatty acid consumption be as low as possible while consuming a nutritionally adequate diet."

The implications of this report are pretty radical. Margarine, for instance, must be unsafe in any quantity -- never mind that the federal nutrition nannies have spent the last 30 years weaning us away from butter in favor of this supposedly "heart-healthy" substitute. There are also no safe amounts of vegetable shortening or food cooked or made with shortening such as pastries, crackers, and fried foods. All of them contain the dreaded trans fats -- vegetable oils that have been altered to be firm at room temperature.

Don't throw away your favorite foods just yet, however. These recommendations don't have much scientific substance. First, there is no evidence at all that trans fats increase heart disease risk in humans. None of the six studies of human populations consuming trans fats come close to linking them with heart disease. No doubt this is why the Institute of Medicine barely even mentioned their existence in its report and didn't rely on them in the slightest to support its conclusion.

Instead, the report relied on laboratory and clinical studies reporting that trans-fat consumption increased low-density lipoprotein cholesterol levels. This is a far cry, though, from scientifically linking trans fats with heart disease.

Moreover, it's not even clear that elevated cholesterol necessarily leads to heart disease and death. In the much-vaunted Framingham Heart Study -- where 5,200 men and women in Framingham, Mass., have been extensively studied in over 1,000 published reports since 1948 -- high cholesterol was not associated with increased heart disease risk after age 47. After age 47, in fact, those whose cholesterol went down had the highest risk of a heart attack. "For each 1 mg/dl drop of cholesterol there was an 11 percent increase in coronary and total mortality," reported the study's authors.

Harvard University researcher Walter Willett acknowledged to science writer Gary Taubes in a recent New York Times Magazine cover story, "What If Fat Doesn't Make You Fat," that though our cholesterol levels have been falling, the incidence of heart disease has not. "That is very disconcerting. It suggests that something else bad is happening," Mr. Willett commented.

Yes, well, whatever "bad" is happening, there certainly is no cause to believe that it's trans fats. Mr. Willett's acknowledgment that the cholesterol-heart disease link is more myth than fact is particularly noteworthy since he is largely responsible for railroading trans fats.

Mr. Willett co-authored every study that claims to link trans-fat consumption with heart-disease risk. Despite his claims, these studies invariably report no or weak statistical associations between trans-fat consumption and heart-disease incidence, and do not rule out other risk factors.

Conveniently, Mr. Willett also co-authors review articles of the trans-fat studies -- including his own -- in which he reiterates his dubious conclusions. Is it too much to ask for some independent researcher -- that is, someone independent from Mr. Willett -- to replicate his claims before the FDA, the Institute of Medicine, and McDonald's lynch trans fats?

My favorite Willett study that fails to link trans fats with heart disease -- one involving 90,000 nurses followed for 20 years -- also fails to link total fat intake, saturated-fat intake, animal-fat intake and cholesterol intake with heart disease.

This is no surprise.

As Mr. Taubes pointed out in his article, the simplistic notion that dietary fat is bad was a political and business judgment, not a scientific one. Despite ambiguous science, in 1977 a Senate committee led by Sen. George McGovern issued a report advising Americans to consume less fat to avoid "killer diseases," then supposedly sweeping the country. The politically dutiful National Institutes of Health soon joined the antifat bandwagon, a move that spawned the low-fat food industry -- a boon to consumer choice but not necessarily one with a beneficial health impact.

McDonald's may be able to pull off the great cooking oil switch without a noticeable flavor difference, and consumers may think they're eating healthier. But there's no evidence they, in fact, will be. In any event, food cooked in the new oil will have the same calories as foods cooked in the old oil. Meet the new oil, the same as the old oil.

McDonald's wants to be a leader in the newthink of "corporate social responsibility." That's fine, but imposing junk science on consumers is not a good start.

Mr. Milloy, a scholar at the Cato Institute and publisher of JunkScience.com, is the author of "Junk Science Judo: Self-defense Against Health Scares and Scams" (Cato Institute, 2001).

Updated September 9, 2002

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