I Can’t Believe It’s Not Science
Consuming butter does not increase the risk of heart disease, a recent study found. Those who believed in the accuracy of U.S. government dietary guidelines — which for decades have demonized saturated fats — were doubtless taken by surprise. But for those of us who follow nutrition and politics, it’s just another government nutritional “gospel” that science has revealed to be misguided.
Yet, government agencies continue to spend millions to nudge consumers into following guidelines that may do little to improve health for most and may even result in harm.
For nearly half a century, the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services (HHS) have put out dietary guidelines telling Americans to eat less sodium, cholesterol, and saturated fat — i.e., red meat and full-fat dairy, including butter — and to eat more whole grains, fruits, and vegetables, among other directives. These recommendations emanated from hearings held in the mid-to-late 1970s by the Senate Select Committee on Nutrition and Human Needs, despite a “boisterous mob of critics,” including those within the scientific community who pleaded with the Committee to wait for more research “before we make announcements to the American public.” In response, Committee Chairman Sen. McGovern responded that “Senators don’t have the luxury that the research scientist does of waiting until every last shred of evidence is in.”
Since the Committee issued its report in 1977, those patient research scientists have repeatedly called into question or undermined many of the Committee’s original recommendations. Increasing the level of dietary salt, for example, appears to lead to hypertension only in a small percentage of the population; and in some, lowering dietary salt can, in fact, result in higher blood pressure. Moderate levels of dietary cholesterol no longer seems to be linked to heart disease. And full-fat dairy has been shown to reduce the risk of obesity and diabetes.
To be fair, the Dietary Guidelines Advisory Committee (DGAC), which is comprised of a handful experts, diligently evaluate the research on what constitutes a healthy diet every five years. And sometimes they alter recommendations to reflect the changing scientific understanding. For example, the most recent guidelines finally did away with limits on dietary cholesterol and backed away — ever so slightly — from previously stringent sodium recommendations. But such changes are rare and often come long after shifts within the scientific community. The real issue is that government agencies pass judgement on developing science in the first place.
Scientific progress is not achieved via committee — whether Congressional or scientific. Rather, science advances toward an understanding of reality through years — often decades — of research, with scientists fighting for their own hypotheses. They present, defend, test, and modify their ideas over time. Whichever side offers the most compelling argument “wins” by gradually becoming the predominant theory. Soon, other researchers gravitate toward that theory, basing their own research on it.
Congress, of course, is an inherently political entity. And so when it — or any other government-appointed body — privileges one theory over another, it creates bias that trickles down to the research community. The problem is not simply that the government makes decisions on the basis of imperfect information, but that government intervention, itself, can distort the development of research.
For example, the theory that dietary fat plays a large role in cardiovascular disease was controversial in the scientific community, even as the government began relying on it to develop the first federal nutritional guidelines. In fact, a lot of the existing research contradicted it. Nevertheless, the theory flourished. Why? In part, no doubt, because researchers — many of whom rely on government grants — faced risks associated with bucking the new zeitgeist created by the government.
Fortunately, the latest dietary guidelines limit the ultra-low sodium recommendation of 1,500 mg per day to those with hypertension or pre-hypertension. But the committee members still warn that food manufacturers “should reformulate foods to make them lower in overconsumed nutrients,” including salt, to help Americans — who consume an average of 3,400 mg of sodium a day — get to their recommended limit of 2,300 mg a day. Lo and behold, the White House pushed the FDA to create “voluntary” sodium reduction guidelines for food manufacturers — all this despite the tenuous connection between higher sodium and hypertension and a recent study (commissioned by the government) that found no benefit in consuming less than 2,300 mg of sodium a day for most people.
Had the government refrained from issuing these recommendations, experts might have focused, instead, on efforts to encourage increased potassium intake by eating more fruits and vegetables. This has been shown to reduce blood pressure effectively while having fewer unintended side effects and possibly conferring unintended benefits.
There are ways that federal agencies can promote dietary advice that could benefit most of the population (such as recommendations to eat more fruit and vegetables). But, in general, nutrition is far too complex and personal an issue for a one-size-fits all, top-down approach. It’s time for the government to relinquish its influence over the scientific and medical communities and let individuals (and their doctors) determine their own optimal diets.
Originally posted to Real Clear Policy.