Newly uncovered documents reveal that 50 years ago the sugar industry gave secret support to prominent Harvard researchers to write an influential series of articles in the New England Journal of Medicine that downplayed the negative effects of sugar.
Instead, the articles shifted the blame from sugar to fat as the "dietary culprit" behind heart disease.
In recent years there has been growing awareness that decades of dietary policy demonized fat and ignored or played down the dangers of increased consumption of carbohydrates and sugars. Many believe this policy had a significant adverse effect on public health, contributing to the obesity and diabetes epidemics.
In the new paper, , DDS, MBA, of U.C. San Francisco and colleagues examined archives containing letters between the Sugar Research Foundation (SRF), the predecessor to today's Sugar Association, and prominent Harvard researchers, including the late , chair of Harvard's School of Public Health Nutrition Department, and , a professor in Stare's department. Hegsted died in 2009.
In the mid-1960s the SRF sought to counter research suggesting that sugar was a more important cause of atherosclerosis than dietary fat. The SRF invited Stare to join its scientific advisory board and approved funds -- eventually amounting to nearly $50,000 in 2016 dollars -- to support a review article that would respond to the research showing the danger of sucrose. In a letter to Hegsted the SRF gave a clear indication of its agenda:
"Our particular interest had to do with that part of nutrition in which there are claims that carbohydrates in the form of sucrose make an inordinate contribution to the metabolic condition, hitherto ascribed to aberrations called fat metabolism. I will be disappointed if this aspect is drowned out in a cascade of review and general interpretation."
Hegsted reassured the SRF: "We are well aware of your particular interest in carbohydrate and will cover this as well as we can." As the paper was being written the authors shared drafts with and gave progress updates to the SRF. But, the authors acknowledge, there is no direct evidence that the SRF directly influenced the content of the article.
In 1967 NEJM published a two-part review article, "Dietary Fats, Carbohydrates and Atherosclerotic Disease" with no mention of the SRF's support and participation. The authors state that there is "only one avenue by which diet may affect the development and progression of atherosclerosis" and that this can be done "by influencing the levels of serum lipids, especially serum cholesterol."
They go on to "conclude, on the basis of epidemiologic, experimental and clinical evidence, that a lowering of the proportion of dietary saturated fatty acids, increasing the proportion of polyunsaturated acids and reducing the level of dietary cholesterol are the dietary changes most likely to be of benefit." By contrast, they "conclude that the practical significance of differences in dietary carbohydrate is minimal in comparison to those related to dietary fat and cholesterol."
Kearns and colleagues show that the Harvard authors applied different levels of rigor in their assessment of the literature examining dietary fats and carbohydrates. Evidence suggesting that dietary fat was not important was heavily discounted.
Like nearly all other medical journals NEJM now requires authors to disclose all relevant conflicts of interest, but this has not put an end to industry influence. In recent years, for instance, t emphasizing the importance of exercise over nutrition in weight control became a public scandal.
In a the Sugar Association said it acknowledged that it "should have exercised greater transparency in all of its research activities, however, when the studies in question were published funding disclosures and transparency standards were not the norm they are today." But the Association continues to defend sugar, stating that "the last several decades of research have concluded that sugar does not have a unique role in heart disease."
quotes Walter Willett, MD. DrPH. who is the current chair of the department of nutrition and the Fredrick John Stare Professor of Epidemiology and Nutrition at the Harvard School of Public Health. Willett told STAT he knew Hegsted and "defended him as a principled scientist." Willett said that "I very much doubt that he changed what he believed or would conclude based on industry funding." But Willett conceded that "it is also possible that these relationships could induce some subtle bias, even if unconscious."
Nina Teicholz, author of , said that the article "shows how the food industry manipulates nutrition science -- something that still goes on today and has largely been given a pass. Most nutrition news is reported without scrutinizing conflicts of interest, and researchers themselves often try to obscure their industry funding. Yet this has been the state of the field in nutrition science in the US from its start -- going back to the 1940s, when food manufacturers realized that they could influence nutrition science by funding the trusted academic experts who produce it (as I document in my book)."
Teicholz said that the paper "doesn't produce a smoking gun," since it "doesn't connect the dots to show that this effort had an effect on national policy." But, she said, the paper does show "that early on, in the 1950s, the sugar industry was alert to the idea that if Americans adopted the low-fat diet, they'd shift their calories over to eat more carbs -- and that those carbs would include sugar. This is exactly what happened when the American Heart Association adopted the low-fat diet in 1970 and when the U.S. Dietary Guidelines adopted the low-fat diet in 1980. Now we know that this low-fat, high-carb diet has clearly been a disaster for American health, which is why the Guidelines, just last year, dropped it. Hopefully the harm caused by the food industry can now start to be undone."