I’m not a conspiracy theorist. Really. But as I wade through the thicket of science studies and rhetoric of science readings I have on my desk, I am more and more impressed with the power of paradigmatic thinking to distort how scientific knowledge is produced and disseminated.
Daisy Zamora and company have once again climbed in their wayback machine to reanalyze data from the Minnesota Coronary Survey, which began in 1968. The vegetable oil intervention reduced saturated fat intake by about half and cholesterol consumption by about two-thirds, while nearly tripling the intake of polyunsaturated fat. Surprise, surprise–they found that although the vegetable oil intervention reduced cholesterol levels, the intervention also led to more heart attacks and increased risk of death. [The press release on the study is here; the study itself is here.]
Let me just add that the original study outcomes–which did not support the diet-heart hypothesis even then–were not published until many years after the study ended, in fact, after its primary investigator retired.
So, we’ve seen something like this with a red-meat-causes-cancer publication, a low-carb-more-calories-more-weight-loss one, and one of Zamora’s earlier studies, which she had to move mountains to get published.
Zamora and her team’s previous trip in the wayback machine turned up some interesting findings then too, which suggested that vegetable oils, far from being the “healthy” alternative to butter, might actually be contributing to increased risk of death from heart disease.
Zamora and her co-investigators politely refer to these sort of anomalies as “incomplete publication,” as in:
“… incomplete publication of important data has
contributed to the overestimation of benefits – and the underestimation of potential risks – of replacing
saturated fat with vegetable oils rich in linoleic acid.”
All I want to say, before going back and burying my head once again in my books, is that
1) Daisy Zamora and Christopher Ramsden are rockstars, and
2) “incomplete publication” of results from diet-heart trials is part of the reason that the folks at the USDA and DHHS have published guidelines where “oils” get to have their own category.
They aren’t trying to kill us on purpose. Really.
***********************************************************************
Update: You know you’ve increased the amount of sunshine in the world when your work gets Walter Willett to offer up yet another snotty comment (see here for previous peevishness) about any research that doesn’t align with his: “Walter Willett, the chairman of the nutrition department at the Harvard T.H. Chan School of Public Health, called the research ‘irrelevant to current dietary recommendations’ that emphasize replacing saturated fat with polyunsaturated fat.”
He’s right of course. Any science that doesn’t uphold the orthodoxy really is irrelevant to current dietary recommendations.
