Posts Tagged ‘Dietary Guidelines for Americans’

April 1, 2012.  Piltdown, East Sussex, UK . Two prominent researchers, Drs. Ferdinand I. Charm and June E. Feigen of the University of Piltdown Center for Applied Nutrition (PCAN), submit the following guest review on a ground-breaking area of nutrition.

Nutrition is frequently accused of being a loose kind of science, not defining its terms and speaking imprecisely.  Complex carbohydrates, for example, still refer, in organic chemistry, to polysaccharides such as starches and for many years, it was absolute dogma in nutrition that complex carbohydrates were more slowly absorbed than simple sugars.  Science advances, however, and when measurements were actually made it was found not to be so simple, giving rise to the concept of the glycemic index.  The term “complex,” had since then been used loosely but has currently evolved to have a more precise meaning derived from mathematics, that is, as in complex numbers, having a real part and an imaginary part although the recent Guidelines from the USDA make it difficult to tell which is which.  In any case, the glycemic index has expanded to the concept of a glycemic load and now there is even more hope on the horizon.

Nutrition has borrowed a page from particle physics in the application of quantum chromodynamics. In the way of background, the discovery of the large number of subatomic particles and the need to classify them meant that designations had to go beyond charge and spin to include strangeness and the three flavors of quarks.  Ultimately, it was decided that quarks have an additional degree of freedom, called color and the strong interaction was identified as a color force.  A large amount of evidence supports this idea with interaction via the gluons.

Nutritional Chromodynamics.

A similar idea has arisen in nutrition and it is now clear that the more color, the better and extensive experimental work at CARN is currently under way (Figure 1). The recent CRAYOLA  study showed the value of spectral nutrient density. Support for the theory was summarized in a recent press release:

Blueberries were up there, the wild type being the best.

 “The wild blueberries are blue inside as well as blue outside. The ones we normally eat are sort of white inside. So there are more of the antioxidants in these all-blue blueberries.”

Along the line of color is good, cranberries were close behind as were blackberries.

 But what about vegetables?

 Dried red beans topped the list overall–red kidney and pinto beans were also in the top 10. But surprisingly, so are artichokes. “This is sort of interesting because they are not deeply colored, the inside, the part that we actually consume is white or very pale green but never the less they contain very large amounts of antioxidants.”

 There are nuts that did not make it into the top twenty but did have high enough content worthy of mention– pecans, hazelnuts and walnuts were the ones with the greatest antioxidant content. But the antioxidants are concentrated, so you need only a handful a day to get the amount you need.

 The problem here may be the bland coloration of the nuts. This has been jarring to some theorists, leading many to question whether the Standard Model of nutrition will last, or whether the highly abstract bean-string theory will ultimately prevail.  The recent identification of chocolate with the dark matter that fills the majority of the universe, however, has established the field of nutritional chromodynamics.  Still, critics point to the problem of red meat, one of the very few foods that actually decreased during the epidemic of obesity.  By applying the USDA Nutritional Guidelines, however, this result can be made to vanish.

Figure 1 Souper-Collider at CARN (Centre Alimentaire de Recherche Nucléaire).

Although this is pretty convincing, there is the uncertainty principle.   Because the outcome of a nutritional experiment and its support for the experimenter’s theory rarely commute, it is impossible to simultaneously measure outcome and whether the results mean anything.  Again borrowing from particle physics, there is the concept of the virtual particle that mediates interaction between other particles.  The evolving principle in the field of nutritional chromodynamics is the existence of the  mayon, the virtual particle that mediates the so-called Dietary Weak Interaction or DWI, as in “phytochemicals may prevent cancer.”

And then there is the matter of Quark. Most physicists know that Quark is the German word for sour cream and many physicists on tour in Germany have their picture taken in front of delicatessens selling Quark (at least those who don’t have their picture taken in front of a jewelry store).  Less widely known outside of the German-speaking countries is that Quark colloquially means nonsense or trash.  In any case, it’s pretty clear at this point that, the Tevatron results notwithstanding, blueberries and sour cream are the real Top Quark.

In 1985 an NIH Consensus Conference was able to “establish beyond any reasonable doubt the close relationship between elevated blood cholesterol levels (as measured in serum or plasma) and coronary heart disease” (JAMA 1985, 253:2080-2086).

I have been making an analogy between scientific behavior and the activities of the legal system and following that idea, the wording of the conference conclusion suggests a criminal indictment. Since the time of the NIH conference, however, data on the role of cholesterol fractions, the so-called “good (HDL)” and “bad (LDL)” cholesterols and, most recently, the apparent differences in the atherogenicity of different LDL sub-fractions would seem to have provided some reasonable doubt. What has actually happened is that the nutrition establishment, the lipophobes as Michael Pollan calls them, has extended the indictment to include dietary fat, especially saturated fat at least as accessories on the grounds that, as the Illinois Criminal Code put it “before or during the commission of an offense, and with the intent to promote or facilitate such commission, … solicits, aids, abets, agrees or attempts to aid… in the planning or commission of the offense. . . ..”

A major strategy in the indictment of saturated fat has been guilt by association.  The American Heart Association (AHA), which had long recommended margarine (the major source of trans-fats), has gone all out in condemning saturated fatty acids by linking them with trans-fats.  The AHA website has a truly deranged cartoon film of the evil brothers: “They’re a charming pair, Sat and Trans.  But that doesn’t mean they make good friends.  Read on to learn how they clog arteries and break hearts — and how to limit your time with them by avoiding the foods they’re in.”. While the risk of trans-fats is probably exaggerated — they are a small part of the diet — they have no benefit and nobody wants to defend them; dietary saturated fat, however, is a normal part of the diet, is made in your body and is less important in providing saturated fatty acids in the blood, than dietary carbohydrate.  Guilt by association is a tricky business in courts of law — just having a roommate who sells marijuana can get you into a good deal of trouble — but it takes more than somebody saying that you and the perpetrator make a charming pair.

The failure of the diet-cholesterol-heart hypothesis in clinical trials as been documented by numerous scientific articles and especially in popular books that document the original scientific sources. It is unknown what the reaction of the public is to these books.  However, amazingly, there is only one book I know of that takes the side of the lipophobes and that is Daniel Steinberg’s Cholesterol Wars. The Skeptics vs. the Preponderance of Evidence. A serious book with careful if slightly biased documentation and an uncommon willingness to answer the critics,  it is worth reading.  I will try to discuss it in detail in this and future posts.  First, the title indicates a step down from criminal prosecution.  “Preponderance of the evidence” is the standard for conviction in a civil court and is obviously a far weaker criterion.  One has to wonder why it is that the skeptics have the preponderance of the popular publications — if the scientific evidence is there and health agencies are so determined that the public know about this, why are there so few —  maybe only this one — rebutting the critics.

The Skeptics vs. the Preponderance of Evidence

In any case, what is Steinberg’s case?  The indictment on page 1 is somewhat different than one would have thought.

“….the [lipid] hypothesis relates to blood lipids not dietary lipids as the putative directly causative factor. Although diet, especially dietary lipid is an important determinant of blood lipid levels, many other factors play important roles. Moreover, there is a great deal of variability in response of individuals to dietary manipulations. Thus, it is essential to distinguish between the indirect “diet-heart” connection and the direct “blood lipid — hard” connection failure to make this distinction has been a frequent source of confusion. (his italics)”

What?  Are we really supposed to believe that diet is an incidental part of the lipid hypothesis?  Are we supposed to believe that our cholesterol is just a question of the variability of our response to diet.  Has the message really been that diet is not critical and that heart-disease is just the luck of the draw (until we start taking statins)?  This is certainly the source of confusion in my mind.  Of course by page 5, we are confronted with this:

“In 1966, Paul Leren published his classic five-year study of 412 patients who had had a prior myocardial infarction. He showed that substitution of polyunsaturated fat and saturated fat-rich butter-cream-venison diet favored by the Norwegians reduced their blood cholesterol by about 17 per cent and kept it down.  The number of secondary current events in the treated group was reduced by about one-third and the result was significant at the p < 0.03 level.”

In a future post, I will describe Paul Leren’s classic five-year study which, by 1970, had a follow-up to eleven years and the results will turn out not to be as compelling as described by Steinberg.  For the moment, it is worth considering that, given the strong message, from the AHA, from the American Diabetes Association, from the NIH Guidelines for Americans, the criterion really should be beyond a reasonable doubt. There shouldn’t be even a single failure like the Framingham Study or the Women’s Health Initiative. In fact, the preponderance of the evidence when you add them all up, isn’t there.

Following the government’s nutritional advice can make you fat and sick.

City Journal, May 10, 2011

Last October, embarrassing e-mails leaked from New York City’s Department of Health and Mental Hygiene disclosed that officials had stretched the limits of credible science in approving a 2009 antiobesity ad, which depicted a stream of soda pop transforming into human fat as it left the bottle. “The idea of a sugary drink becoming fat is absurd,” a scientific advisor warned the department in one of the e-mails, a view echoed by other experts whom the city consulted. Nevertheless, Gotham’s health commissioner, Thomas Farley, saw the ad as an effective way to scare people into losing weight, whatever its scientific inaccuracies, and overruled the experts. The dustup, observed the New York Times, “underlined complaints that Dr. Farley’s more lifestyle-oriented crusades are based on common-sense bromides that may not withstand strict scientific scrutiny.”

Under Farley and Mayor Michael Bloomberg, New York’s health department has been notoriously aggressive in pursuing such “lifestyle-oriented” campaigns (see the sidebar below). But America’s public-health officials have long been eager to issue nutrition advice ungrounded in science, and nowhere has this practice been more troubling than in the federal government’s dietary guidelines, first issued by a congressional committee in 1977 and updated every five years since 1980 by the United States Department of Agriculture. Controversial from the outset for sweeping aside conflicting research, the guidelines have come under increasing attack for being ineffective or even harmful, possibly contributing to a national obesity problem. Unabashed, public-health advocates have pushed ahead with contested new recommendations, leading some of our foremost medical experts to ask whether government should get out of the business of telling Americans what to eat—or, at the very least, adhere to higher standards of evidence.

Until the second half of the twentieth century, public medicine, which concerns itself with community-wide health prescriptions, largely focused on the germs that cause infectious diseases. Advances in microbiology led to the development of vaccines and antibiotics that controlled—and, in some cases, eliminated—a host of killers, including smallpox, diphtheria, and polio. These advances dramatically increased life expectancy in industrialized countries. In the United States, average life expectancy improved from 49 years at the beginning of the twentieth century to nearly 77 by the century’s end.

As the threat of communicable diseases receded, public medicine began to turn its attention to treating and preventing health problems that weren’t germ-caused, such as chronic heart disease and strokes, the death rates for which seemed to be soaring after World War II. Some observers cautioned that the apparent increase might be the result of diagnostic advances, which had improved doctors’ ability to detect heart ailments. This possibility, however, failed to deter the press and advocacy groups like the American Heart Association from declaring the arrival of a frightening epidemic.

One theory blamed the problem on the American diet, and in particular on cholesterol—both the kind that you ingest when you eat animal products and the kind that your body produces when you eat saturated fats. It wasn’t an unreasonable idea; cholesterol is, after all, one component of the plaque that clogs arteries and causes heart attacks and strokes. But isolating the true causes of coronary disease proved elusive. Multiple factors—not just diet but other personal habits, such as smoking, and genetics as well—were potential contributors. And measuring the influence of diet was especially difficult because of big variations among individuals in everything from blood composition to their response to different foods. Numerous studies on diet proved so inconclusive that in 1969, the National Institutes of Health found no hard evidence that what people ate had a significant impact on heart disease.

Nevertheless, in the 1970s, Democratic senator George McGovern’s Select Committee on Nutrition and Human Needs decided to fight the apparent epidemic by making recommendations on nutrition. “Our diets have changed radically within the past 50 years,” McGovern declared, “with great and very often harmful effects on our health.” As science writer Gary Taubes notes in Good Calories, Bad Calories, the McGovern committee, in coming up with its diet plan, had to choose among very different nutritional regimes that scientists and doctors were studying as potentially beneficial to those at risk for heart disease. Settling on the unproven theory that cholesterol was behind heart disease, the committee issued its guidelines in 1977, urging Americans to reduce the fat that they consumed from 40 percent to 30 percent of their daily calories, principally by eating less meat and fewer dairy products. The committee also advised raising carbohydrate intake to 60 percent of one’s calories and slashing one’s intake of cholesterol by a quarter.

Some of the country’s leading researchers spoke out against the guidelines and against population-wide dietary recommendations in general. Edward Ahrens, an expert in the chemistry of fatty substances at Rockefeller University, characterized the guidelines as “simplistic and a promoter of false hopes” and complained that they treated the population as “a homogenous group of [laboratory] rats while ignoring the wide variation” in individual diet and blood chemistry. The Food and Nutrition Board of the National Academy of Sciences released its own dietary suggestions, which saw “no reason for the average healthy American to restrict consumption of cholesterol, or reduce fat intake,” and just encouraged people to keep their weight within a normal range.

Even members of McGovern’s committee demurred. In a supplemental foreword to the second edition of the guidelines, ranking Republican senator Charles Percy acknowledged that the scientific record included “extreme diversity of opinion.” Canada’s Department of National Health and Welfare, Percy noted, had recently declared that “evidence is mounting that dietary cholesterol may not be important to the great majority of people”; Great Britain’s Department of Health and Social Security had reached a similar conclusion in 1974. Percy concluded that it was important to inform the public “not only about what is known, but what is controversial.”

Still, the low-fat guidelines gained traction in an era when food advocacy and vegetarianism were rising, as Taubes relates. In 1968, Paul Ehrlich had published his apocalyptic bestseller, The Population Bomb, prophesying mass starvation because the earth could no longer provide enough food for humanity. Ehrlich’s book was out of date as soon as it appeared, thanks to scientific advances that made agriculture more productive worldwide. But it nevertheless gave ammunition to advocates who urged people in developed countries to eat fewer animal products so that the world’s poor, supposedly hungrier and hungrier, could consume more of the grain that wealthy nations turned into feed for domestic animals. In 1971, Frances Moore Lappé’s vegetarian manifesto Diet for a Small Planet hit the bestseller list.

A new kind of health-care advocate, evincing a passion far removed from disinterested scientific inquiry, also took up the campaign for a vegetable-based, low-fat diet. A good example was the Center for Science in the Public Interest, which in 1975 organized a National Food Day that included, the New York Times reported, an “all-out attack” on foods that it considered harmful. On the hit list: prime beef, high in fat and cholesterol.

When the McGovern committee issued its guidelines, these advocacy groups attacked opponents as shills for the food industry—dismissing the National Research Council’s more restrained dietary recommendations, for instance, because some of the scientists who worked on them also served as consultants to industry groups like the Egg Council. By contrast, the advocates noted, the McGovern guidelines were largely the work of a committee staffer, a former newspaper reporter whose very lack of scientific expertise meant that he had no such conflicts.

But the line between advocate and policymaker was blurring on both sides of the debate. One of the important figures promoting the dietary guidelines was Assistant Secretary of Agriculture Carol Foreman, who had formerly been director of the Consumer Federation of America, a cosponsoring organization of National Food Day. “People were getting sick and dying because we ate too much,” she told Taubes. She urged government scientists to tell Americans what to eat, even if “it’s not the final answer.”

The McGovern dietary recommendations weren’t just ahead of the science, though; they were racing ahead of it. Two of the most important U.S. government–sponsored studies on the role of fat and cholesterol in heart disease didn’t appear until the early 1980s, long after the committee had promulgated its advice. The results hardly cleared things up. The first study, known as the Multiple Risk Factor Intervention Trial, followed 12,866 people between the ages of 35 and 57 at risk for heart disease. Some of these subjects were placed on a low-fat, low-cholesterol diet; others were merely told to keep seeing the family doctor. The study found no statistically significant difference in mortality rates between the two groups.

The results of the second study, the Lipid Research Clinics Coronary Primary Prevention Trial, appeared in 1984 and continue to spark debate. Using the drug cholestyramine to reduce high cholesterol rates in a group of male test subjects, the study reported a lower death rate for those on the drug than for subjects who took a placebo. Did this mean that cholesterol was to blame for heart disease, after all? Some observers, including Ahrens, cautioned that the average cholesterol level of the American public was far lower than that of the test group taking cholestyramine, meaning that there was nothing in the study to suggest that a nationwide effort to change citizens’ diets would make much difference in public health. But the press seemed to prefer a narrative that made diet a major cause of heart attacks. A 1984 Time cover story about cholesterol showed a dinner plate turned into an unhappy face, with two sunny-side-up eggs the frazzled-looking eyes above a frowning strip of bacon.

The scientific controversy grew more intense. In 1992, an authoritative review of 19 cholesterol studies worldwide found that, while men with cholesterol levels above 240 were disproportionately likely to suffer heart attacks, men with cholesterol levels below 160 were disproportionately likely to die from all causes, including lung cancer, respiratory disease, and digestive disease—an outcome that suggested a relationship between lowcholesterol levels and disease, something that scientists had never considered. The study also showed no difference in mortality rates for men with cholesterol levels between 160 and 240, even though the guidelines advised keeping levels below 200. Perhaps most surprisingly, the study also found that cholesterol levels made no difference at all in death rates among women. There was little doubt that some public-health researchers wished such research would go away. “Some people don’t want to talk about it,” said Michael Criqui, an epidemiologist at the University of California at San Diego and an associate editor of Circulation, which published the review. “They think it is going to impede public-health measures.”

More recent research has further undermined the cholesterol-as-bad-guy hypothesis. Scientific American summed up the disturbing state of the evidence in April 2010. The magazine cited a meta-analysis—that is, a combination of data from several large studies—of the dietary habits of 350,000 people worldwide, published in The American Journal of Clinical Nutrition, which found no association between the consumption of saturated fats and heart disease. Another recent study noted by Scientific American, by Harvard nutrition and epidemiology professor Meir Stampfer and associates and published in The New England Journal of Medicine, tracked 322 moderately obese people, each following one of three diets: a low-fat, calorie-restricted diet of the sort that the American Heart Association recommends; a so-called Mediterranean diet, rich in vegetables and low in red meat; and a low-carbohydrate diet without any calorie restrictions. Not only did the low-carb dieters lose the most weight, the study found; they also had the healthiest ratio of HDL (so-called good) cholesterol to LDL (bad) cholesterol.

The latest nutritional thinking has indeed zeroed in on carbohydrates as a likely cause of heart disease. Easily digestible carbs, in particular—starches like potatoes, white rice, and bread from processed flour, as well as refined sugar—make it hard to burn fat and also increase inflammations that can cause heart attacks, several studies have concluded. A 2007 Dutch study of 15,000 women found that those who ate foods with the highest “glycemic load,” a measure of portion sizes and of how easily digestible a food is, had the greatest risk of heart disease.

Looking at such evidence, several top medical scientists have concluded that the government’s carb-heavy guidelines may actually have harmed public health. In 2008, three researchers from the Albert Einstein School of Medicine—including the associate dean of clinical research, Paul Marantz, and a former president of the International Hypertension Society, Michael Alderman—observed in The American Journal of Preventive Medicine that since 1977, Americans have largely followed the government’s advice, doubtless as conveyed by the doctors they consulted. Men, for instance, cut their fat intake from 37 percent of their daily calories to 32 percent and increased their carbohydrate intake from 42 percent to 49 percent. Yet over the same three decades, the fraction of American men who were overweight or obese increased from 53 percent of the population to about 69 percent. The doctors wondered whether this correlation was an unintended consequence of telling the entire population to change its eating patterns. “In general,” the doctors wrote, “weak evidentiary support has been accepted as adequate justification for [the U.S. dietary] guidelines. This low standard of evidence is based on several misconceptions, most importantly the belief that such guidelines could not cause harm.” But, they concluded, “it now seems that the U.S. dietary guidelines recommending fat restriction might have worsened rather than helped the obesity epidemic and, by so doing, possibly laid the groundwork for a future increase in CVD,” cardiovascular disease.

It’s true that the particular kind of carbohydrates that the government has always recommended are carbs rich in fiber, which aren’t as quickly digested as those starches implicated by the latest research. But it’s difficult to tell an entire population to change its dietary habits without sowing confusion about such fine points. Further, as an October 2010 article in Nutrition points out, the government’s definition of what constitutes a fiber-rich grain is so broad as to include many foods that might actually promote heart disease because they are too easily digestible. “At a minimum,” says one of the authors of the Nutrition piece, SUNY Downstate Medical Center biologist Richard Feinman, “if you have an area of controversy or ambiguity in the science, you shouldn’t be issuing guidelines to the entire population.”

The guidelines themselves quietly acknowledge that they may have worsened public health. The 2000 version eliminated the recommendation to reduce intake of overall fat in favor of carbs, noting “the possibility that overconsumption of carbohydrates may contribute to obesity.” But that was as far as the government would go. It retained the advice to limit consumption of saturated fat and to keep intake of cholesterol to 300 milligrams per day, for example, even though dietary cholesterol—that is, the cholesterol we ingest by eating animal products—has been discounted by many researchers as a source of plaque buildup. (It was this advice about dietary cholesterol that led doctors, starting in the 1970s, to counsel patients to avoid eggs. Subsequent studies have concluded that any restrictions on eating them are “unwarranted for the majority of people and are not supported by scientific data,” as a 2004 article in The Journal of Nutrition put it.)

Supporters of the guidelines have increasingly resorted to ad hoc, even political, justifications for them. In a 2008 American Journal of Preventive Medicine article, for example, two influential nutritionists, Marion Nestle of New York University and Steven Woolf of the Virginia Commonwealth University Medical Center, admit that “whether the evidence is good enough to recommend population-based dietary changes comes down to a matter of subjective judgment.” But developing dietary recommendations is still a crucial government responsibility, they argue, in part because the government is already heavily involved in food policies. “Dietary guidelines have implications at every level of government, from federal agencies such as the U.S. Department of Agriculture (USDA) to the local school board,” they write, and without clear guidelines, big food industries and special interests could lobby political leaders and shape policy in unhealthy ways. But this argument makes sense only if you assume that the government’s guidelines will be any healthier.

Nestle and Woolf also argue that government’s success in persuading people to stop smoking justifies its efforts to change American eating habits. “If it was paternalistic for the government to advise people how to eat,” they ask rhetorically, “was it equally paternalistic . . . to alert the public about the hazards of tobacco use and to recommend in 1964 that smokers give up cigarette smoking?” But the major scientific dissenters from government dietary policy don’t accuse it of paternalism, though that’s a legitimate argument; they dissent because they find the government’s evidence inadequate and its recommendations potentially harmful.

The government’s response to the growing controversy has been to keep issuing the guidelines—and call for more research. Asked last year about whether the 2010 update would reflect the latest studies challenging previous recommendations, a USDA spokesperson merely suggested that the controversial areas be “put on the list of things to do with regard to more research.” In other words, more research is needed to overturn or withdraw the current recommendations, even though they were based on inconclusive evidence from the start.

Mike Bloomberg, Food Cop

In his 2005 book Prescription for a Healthy Nation, Dr. Thomas Farley wondered why “Americans behave in such an unhealthy way” and concluded that we don’t have the will to overcome the temptations around us, like easy access to junk food. Publishers Weekly noted that the book had “a pervasive tone of puritanical disapproval” and that Farley and his coauthor, Dr. Deborah Cohen, sounded like a “pair of scolds.” In 2008, New York City mayor Michael Bloomberg made the first of the scolds the city’s health commissioner, and Farley hasn’t disappointed. He’s carried on a tradition—begun by Bloomberg and his first health commissioner, Thomas Frieden, now director of the U.S. Centers for Disease Control and Prevention—of pursuing population-wide dietary policies that are aggressive, questionable, and born from the belief that government should regulate Americans’ indulgent behavior.

Early in his tenure, Frieden had his hands full, confronting everything from a SARS scare to a drug-resistant form of HIV. He nonetheless expanded his portfolio beyond these classic public-health threats into the more controversial area of lifestyle recommendations. In 2005, he began a campaign against man-made trans fats of the sort that appear in partially hydrogenated oils, which ultimately led to a ban on them—the first of its kind—in the city’s restaurants. Then the city mandated that chain restaurants include calorie counts in their menus. In 2009, Frieden and then Farley began a nationwide campaign to get food companies to use less sodium. Most recently, the Department of Health and Mental Hygiene has waged a campaign against sugared soda pop, aggressively linking it to human fat in a cause-and-effect relationship that even the city’s own scientific advisors have rejected.

Bloomberg’s interest in the field predates his mayoralty; the nation’s largest school of public-health medicine, at Johns Hopkins University, is named after him in gratitude for his large donations. But the health campaigns that he has run from city hall have made him a national influence. The Harvard School of Public Health Medicine awarded him its top honor in 2007. The 2009 federal health-care legislation commonly known as Obamacare, following New York’s lead, will require chain restaurants nationwide to post calorie counts, while the dietary guidelines issued by the United States Department of Agriculture, picking up where New York left off, are now targeting sodium as a health risk, too.

Among scientists, however, the Bloomberg administration’s crusades are controversial, because they push the limits of what research has shown and ignore the potential unintended consequences of advising entire populations on how to change their diets. In an article titled “The Panic Du Jour: Trans Fats,” New York Times nutrition columnist Gina Kolata noted that studies show trans fats to be no more dangerous than saturated fats. The authors of a 2008 article in The American Journal of Preventive Medicine, “A Call for Higher Standards of Evidence for Dietary Guidelines,” worried that “the net of effects of legal restrictions” on trans fats was unknown and that a ban could backfire if it led Americans to assume that foods without trans fats were healthful. Meanwhile, a study by researchers at New York University of the city’s calorie-posting law found that it had no effect on what consumers bought. Though a quarter of parents in the study claimed to consult the calorie postings before buying food for their kids, their receipts showed no calorie difference between the meals that they’d purchased and those purchased by parents who didn’t look at the postings.

Apparently, none of these controversies gave the Bloomberg administration pause. The city undertook its 2009 campaign against salt despite decades of scientific uncertainty about whether lowering sodium consumption matters to anyone except those few Americans highly sensitive to salt.

The mayor and his health commissioners have exaggerated the potential health benefits of their campaigns, in the process raising fundamental questions about the point at which a government should intervene in public-health matters. Bloomberg himself estimated, for instance, that the trans-fat ban would save “a couple of hundred lives a year in New York City,” a completely untested statement that failed to take into account a host of possibilities—for example, that people might start to consume an alternative to trans fats that would do just as much harm. But such exaggerations are increasingly common in public-health medicine because overstating the beneficial effects of policies helps get them enacted.

As if all this weren’t troubling enough, the USDA, again with uncertain scientific warrant, is now targeting sodium as a public-health menace. Following the lead of New York City’s health department, which is prodding food manufacturers to make their products less salty, the 2010 guidelines recommend that sodium consumption fall as low as 1,500 milligrams a day for those over 51, more than a one-third reduction from the amount that the previous version of the guidelines suggested.

For the general population of healthy Americans, however, that advice may be pointless or, again, even harmful. Decades of research have yielded continuing controversy over the benefits of lowering salt consumption. The science remains so inconclusive that Alderman recently described calls to reduce sodium intake as merely “opinion or common practice,” not science.  Experts like the authors of the October 2010 Nutrition article argue that people with particular health problems, such as hypertension, may indeed suffer from excessive sodium intake. But that’s a far cry from saying that everybody should cut down on salt. Alderman, an expert on hypertension, worries that the war on salt may have unintended consequences; diets that reduce salt intake produce a host of physiological changes, including decreased insulin sensitivity, which can raise the risk of heart disease. None of these concerns has stopped the Center for Science in the Public Interest from waging a zealous public-health crusade denouncing salt as “the deadly white powder you already snort.”

It’s all the more important to understand the problems with the dietary guidelines as the federal government embarks on its new campaign against obesity, which research and clinical experience have shown to be a major factor in ailments like diabetes and chronic heart disease. When the White House announced late last year that First Lady Michelle Obama would lead the fight against childhood obesity and she observed that “we can’t just leave it up to parents,” some prominent conservatives, including columnist Michelle Malkin and former vice presidential candidate Sarah Palin, accused the administration of entering an arena where parents, not the government, should be making decisions.

Opponents of the administration’s plans, however, shouldn’t just debate the government’s proper role in people’s health; they should also point out that its population-wide diet advice goes well beyond what science has established. “Some people in this field act more like zealots with a passion for a cause than scientists waiting for the evidence to support their conclusions,” complains California Polytechnic public-health economist Michael Marlow. As Marlow notes, America’s obesity rate was far lower back when nutrition was largely a parental responsibility, before government became widely involved in the diet-advice business.

The best thing government can encourage Americans to do on the health front may well be to develop their own diet and exercise programs, based on their individual circumstances, in consultation with health-care professionals. Otherwise, public-health medicine risks violating the central principle of medical ethics: First, do no harm.

Steven Malanga is the senior editor of  City Journal  and a senior fellow at the Manhattan Institute.  He is the author of  Shakedown: The Continuing Conspiracy Against the American Taxpayer.  

City Journal  offers a stimulating mix of hard-headed practicality and cutting-edge theory, with articles on everything from school financing, policing strategy, and welfare policy to urban architecture, family policy, and the latest theorizing emanating from the law schools, the charitable foundations, even the schools of public health. Since urban policy encompasses almost all domestic policy questions, as well as the largest issues of our culture and society, the magazine views its canvas as very broad indeed. The magazine holds itself to the highest intellectual, journalistic, and literary standards, aiming to produce intelligent and absorbing reading for intelligent and discerning readers.  

Journal Nutrition  Article: In the face of contradictory evidence: Report of the Dietary Guidelines for Americans Committee

According to the Journal of the American Medical Association (JAMA), the principle of “evidence-based medicine (EBM),” arose in the 1990s [1]. It is widely invoked in the medical literature as a kind of certification that the conclusions of the author are not mere opinions but are backed up by compelling information in biomedical science.  It sounds good. Or does it? It is certainly self-serving and a little bit suspicious, somewhat like Nixon assuring us that he was not a crook.  Evidence based medicine?  What were we doing before?  How was Pasteur able to function in the absence of such an idea?  One thing to think about is that evidence is what is introduced into courts of law.  But not all evidence is admissible. A judge decides what is admissible and there are many precedents, in particular, on what constitutes scientific evidence in a legal proceeding.

EBM relies on a hierarchy of levels of evidence (e.g. Table 1) with the random controlled trial (RCT) as the highest and expert opinion as the lowest.  Recommendations from health agencies and awarding of research grants are frequently justified on conformity to EBM or at least on their placing primary importance on RCTs.

Evidence from the USDA

Early in 2011, the USDA released its 2010 Dietary Guidelines for Americans [2].  With the dates suggesting the backward-looking nature of the Guidelines, they were nonetheless based on the Report of a prestigious committee (DGAC) [3] who, in turn, made much of their reliance on a new Nutrition Evidence Library (NEL). I and my colleagues were invited to submit a critique of the Report by the journal Nutrition. The editor, Michael Meguid indicated that the journal wanted a balanced report, pros and cons.  I called Dr. Meguid:

RDF: You know, the report is not particularly balanced. I’m not sure how you write a balanced review of an unbalanced report.

MM:  You can make the critique as strong as you like as long as you carefully document everything. But what’s your main problem with the Report?

RDF: Well, it makes very strong recommendations in the face of contradictory evidence.

MM: Make that the title of your article.

So we wrote an article called “In the face of contradictory evidence: Report of the Dietary Guidelines for Americans Committee” [4]. The journal was kind enough to make it an open access article and it’s available on this blog. In the end, on titles, we were one-upped by Steven Malanga, whose article in the New York Post was called “Fed’s Food Fog.”

For sure, both the Report and the final Guidelines were the proverbial camel-like production of a committee, tedious, repetitive and stylistic dreadful.  But what about the NEL?  What about the evidence?  Style aside, wasn’t this evidence based medicine?

Where do these guidelines come from? The assumption is that evidence follows its etymologic roots, stuff that is visible, stuff that comes from the sensible and true avouch of our own eyes. In fact, it is most often applied, as in the case of the DGAC, to the most controversial and contentious subjects. Calling something evidence is not enough. So what happens in courts of law? In a court of law, a judge decides on whether the jury can hear the evidence.  Who decides admissibility of the evidence in EBM?

Conflict resolution in science.

Science is a human activity. Conflict, controversy and a resistance to new ideas are well known even in the so-called hard, that is, more mathematical, sciences, and even where there are no outside forces as there was in the case of Galileo.  In the twentieth century, conflicts do not generally impede progress for long. Especially in the physical sciences, there is usually agreement on basic assumptions and on the rules of logic, allowing ultimate acceptance of strong evidence. Competing theories may coexist and supporters of both are likely to admit that they are awaiting reconciliation.

What happens when the spontaneous process of conflict resolution in science breaks down?  What happens in conditions where scientific disagreement is strong and a majority position becomes so dominant that it controls the funding and publication of scientific work and can ignore or repress contradictory evidence and repress exposition of alternative theories.  In essence, how do we deal with a recapitulation of the case of Galileo?

There is no system to decide on the admissibility in the cases considered by EBM.   I am not the first person to point out that EBM is largely the position of experts on one side of a scientific conflict [5], the lowest level of evidence on traditional EBM scales (e.g. “Level III: Opinions of respected authorities… of the US Preventive Services Task Force Systems,” Table 1).  EBM is sustained by those who want to use its particular criteria but these have never been subjected to outside affirmation.

In this situation, where science cannot police itself, we have to look for some outside guidance.  What do the courts do?  As one would expect there, is a long and extensive history of the legal system’s  attempt to deal with what constitutes scientific evidence.  On the chance that the legal perspective may help, I will discuss some of the issues.

Frye and the need for rules.

A key decision in the history of science in the courts is Frye v. United States.  In 1923, a Federal Appeals court ruled that the opinions of experts have to be supported by a scientific community. Frye had been convicted of second-degree murder but appealed on the grounds that he had successfully passed a lie-detector test.  At that time the device was a simple blood pressure machine and an expert witness testified as to the results. The court ruled that the lie-detector test “has not yet gained such standing and scientific recognition among physiological and psychological authorities as would justify the courts in admitting expert testimony‚” affirming the judgment of the lower court.

The ruling in Frye gave rise to the idea of “general acceptance,” and, by analogy, this appears to be the main principle in the admissibility of evidence in the nutrition world.  Sufficiently well established that it could be included in a biochemistry text is the idea that “consumption of saturated fats is positively associated with high levels of total plasma cholesterol and LDL cholesterol and an increased risk of CHD”[6] Known to students as “the Lippincott Book,” Harvey and Ferrier is the best selling biochemistry book in the world and it is correct when it states “Most experts strongly advise limiting intake of saturated fats.”

Most, but not all.  A small but not insignificant minority hold otherwise and whereas they agree that dietary saturated fat may raise blood cholesterol, they can provide overwhelming evidence that it is not associated with cardiovascular disease. This has been demonstrated in almost every large trial.

The problem is described in Marcia Angell’s Science on Trial [7].  Angell explains that Frye was not without its critics ([7], page 126).  Opponents, she wrote,

“claimed somewhat improbably, that it would tend to exclude novel, far-sighted testimony by modern-day Galileos. There is no record of this happening once, let alone often.  Furthermore, even if a modern-day Galileo did not make into court at first, that fact should not stop him from prevailing in the scientific community.  Courts do not determine scientific acceptance, as implied by the argument that we need to keep our courts open to the hidden Galileos in our midst.”

But isn’t this exactly what has happened in nutrition and maybe, in general, in the medical community?  The “experts” control editorial boards, granting agencies and academic departments and are as powerful as the Catholic Church in repressing dissent.  They have prestige and, in many cases, undisputed accomplishments, but does science run on general acceptance? Does majority (of experts) rule?

One of the problems with Frye that lawyers have addressed is a question of identifying the field of academic or scientific field in which the general acceptance is to be considered.  Different disciplines hold to different standards.  In the case at hand, many ideas in nutrition would be dismissed out of hand by biochemists. Many methodologies would be considered absurd by physical scientists: Intention-to-treat is perhaps the most absurd.  It has been pointed out that the question of who is an expert might have applied to the techniques in the original Frye case, at least as it might be implemented today: “If polygraph examiners are selected as the relevant field, polygraph results would be admissible.” (

The epidemic of obesity and diabetes stands as a testament to the failure of the experts.  A small library can be assembled of books attacking establishment medical nutrition. Uffe Ravnskov’s classic Cholesterol Myths is updated in Ignore the Awkward. Gary Taubes’s recent Good Calories, Bad Calories is the most compelling and James Le Fanu’s Rise and Fall of Modern Medicine, the most succinct but just sitting at my desk now I can see a dozen others on the book shelf.  Surprisingly, there has been only one rebuttal, Steinberg’s Cholesterol Wars, the subject of the next post .

Table 1.  Examples of Levels of Evidence from Various Sources. 

US Preventive Services Task Force Systems for ranking evidence about the effectiveness of treatments or screening:

Level I: Evidence obtained from at least one properly designed randomized controlled trial.

Level II-1: Evidence obtained from well-designed controlled trials without randomization.

Level II-2: Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.

Level II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.

Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.


1. Torpy JM, Lynm C, Glass RM: JAMA patient page. Evidence-based medicine. JAMA 2009, 301(8):900.

2. Dietary Guidelines for Americans, 2010 []

3. US Department of Agriculture and US Department of Health and Human Services: Report of the Dietary Guidelines Advisory Committee on the dietary guidelines for Americans, 2010. June 15, 2010. In.; 2010.

4. Hite AH, Feinman RD, Guzman GE, Satin M, Schoenfeld PA, Wood RJ: In the face of contradictory evidence: report of the Dietary Guidelines for Americans Committee. Nutrition 2010, 26(10):915-924.

5. Marantz P, Bird E, Alderman M: A Call for Higher Standards of Evidence for Dietary Guidelines. Am J Prev Med 2008, 34(3):234-239.

6. Harvey R, Ferrier D: Biochemistry, 5th edn. Baltimore and Philadelphia: Lippincott Williams & Wilkins; 2011.

7. Angell M: Science on Trial. New York: W. W. Norton & Co.; 1996.