TCS Daily


Global Warnings: Salt, Fat And The Abuse Of Science

By Kenneth Green - April 9, 2001 12:00 AM

Fatty foods are bad for your heart. Salty foods raise your blood pressure. For decades now, Americans have swallowed these axioms of dietary wisdom, and paid a pretty penny for fat-free and low-salt foods. But recent articles in Science suggest that things may not be as they seem, and the benefits of salt and fat restriction may have been grossly overstated. Indeed, the focus on fat and salt may well have had unintended consequences that lead people to greater risk, not less.

Let's look at fat first. Conventional wisdom has it that eating a diet high in fat is the leading cause of coronary heart disease and a myriad of other illnesses. But as Gary Taubes recent Science article, "The Soft Science of Dietary Fat," makes clear, statements of certainty regarding the relationship between dietary fat and health have been somewhat overstated. In 1984, the president of the American Heart Association at the time opined that if everyone followed government guidelines to reduce dietary fat, "we will have (arteriosclerosis) conquered by the year 2000." Of course, not everyone went along, though many did: the amount of dietary fat in American diets dropped from 40 percent of total calories to 34 percent, and average serum cholesterol levels have dropped as well.

Given the way that dietary authorities portray the strong linkage between fat intake and mortality, one might expect a corresponding decrease in heart disease from the observed reductions in fat intake. But one would expect wrongly - despite the drop of fat intake, in which consumers spent untold millions of dollars eating lower-fat foods, there has been no reduction in the incidence of heart disease at all. Any drops in mortality are attributed not to prevention, but to more aggressive treatment of heart disease. Now, an American Heart Association analyst says, "I don't consider that this disease category has disappeared, or anything close to it."

In fact, the Taubes' article suggests that the tunnel-vision focus on fat, combined with unsupportable claims about the benefits of low-fat diets, may have caused increases in obesity and diabetes rates, while providing little or no benefit in coronary disease reduction.

Well what about salt? The conventional wisdom on salt was that dietary salt led to elevated blood pressure, a leading cause of heart disease, stroke, and kidney failure. Reducing dietary salt intake, it was suggested, would result in huge reductions in the incidence of heart disease and stroke in the general population. But as Taubes pointed out in a 1998 Science article on "The (Political) Science of Salt," the politicization of the debate over salt was severe. In 1976, then-president of Tufts University called salt "the most dangerous food additive of all." A 1978 campaign by the Center for Science in the Public Interest called salt "the deadly white powder you already snort," and lobbied Congress to require food labeling on high-salt foods.

But reality doesn't seem to be living up to the hype. As Taubes points out, "After decades of intensive research, the apparent benefits of avoiding salt have only diminished. This suggests either that the true benefit has now been revealed and is indeed small, or that it is nonexistent, and researchers believing they have detected such benefits have been deluded by the confounding influence of other variables."

As with dietary fat, the tunnel-vision focus on salt may well have done more harm than good. As Dr. David A. McCarron pointed out in his 1998 article on "Diet and Blood Pressure," "The emphasis on sodium as the single dietary culprit is counterproductive to our significantly reducing cardiovascular risk for most of us and diverts attention from the issues we need to address."

Beside simply missing the mark on their claims and inviting unintended consequences, the debates over salt and fat show hallmarks of politicization virtually identical to that taking place in the debate over global warming, over environmental chemicals, and over genetically modified organisms.

First is the isolation and demonization of anyone trying to overturn the applecart. As the 2000 Science article on fat points out, through the years, "skeptics and apostates have come along repeatedly, only to see their work almost religiously ignored as the mainstream medical community sought consensus on the evils of dietary fat." Does this seem familiar? It should. In a recent lecture to his college students, Al Gore suggested that for the media to even cover contrary views of climate change was illegitimate, and didn't serve the public trust.

Second is the labeling of anyone who disagrees with orthodoxy as being an industry stooge. On salt, the 1998 article points out that "many who advocate salt reduction insist publicly that the controversy is 1) either nonexistent, or 2) due solely to the influence of the salt lobby and its paid consultant-scientists. The article quotes Jeff Cutler, a research director for the National Institutes of Health as saying that even publishing articles about the controversy would "play into the hands of the salt lobby." The article goes on to explain that "over the years, advocates of salt reduction have often wielded variations on the 'totality of the data' defense to reject any finding that doesn't fit the orthodox wisdom." Familiar? Several years ago, then-Secretary of Interior Bruce Babbitt actually claimed that anyone disputing the scientific certainty of global warming was "Un-American," and implied they were all stooges of oil interests.

From global warming, to environmental chemicals to low-level air and water pollutant exposure, any divergence from the claims of radical environmentalists that "the science is in and we must act" are treated as heresy, and charges of science-for-sale are heard constantly. The politicized debate over salt and fat, what some call the "fifth major food group," offers a cautionary tale to remember when impassioned advocates argue that the science is in, we must act now, and anyone who disagrees is an industry-funded skeptic.

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