Retrospective #434: Watch out! Your doctor thinks he/she knows about nutrition!

“Do you discuss nutrition with your patients?” the Tufts Friedman School of Nutrition Science and Policy survey asked physicians. Three-quarters of them replied “always” or “most of the time.” “Do you feel qualified to talk about nutrition with your patients?” Again, 3 out of 4 said, “Yes.” To which I say to patients, “Watch out!”

I have cause to be concerned. The Medscape article which reported the findings links them to two pieces: 1) A “recent study” that “associates…a sub-optimal diet” with “a substantial proportion of deaths in the United States due to heart disease, stroke and diabetes,” and 2) another that nudges physicians to “know what advice to give.” It couches this advice as “evidence-based nutritional advice” to help healthcare professionals deal with “information overload” on diet and nutrition. It quickly becomes clear that the whole point – the pretext for the Tufts “survey” – was to “educate” physicians and other healthcare professionals with “know(ing) what advice to give,” i.e., Tufts’ POV.

The generalized statement that there’s an association of “heart disease, stroke and diabetes” with a sub-optimal diet – a very strong association – is true enough. Deaths from heart disease and stroke are much higher among type 2 diabetics and “pre-diabetics.” This association has led to the term “cardiometabolic disease” (CMD). But, again, on which diet did they become diabetic and develop heart disease? The Tufts answer is epidemiological: an “association.”

The study was presented at the American Heart Association Epidemiology and Prevention-Lifestyle and Cardiometabolic Health (EPI-Lifestyle) 2017 Scientific Session. The findings were also commented on in Medscape by researchers from the Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention Epidemiology. More epidemiology! Epidemiology suggests hypotheses, not cause and effect!

Why is that significant? Because epidemiology can only address “associated with” and “related to” findings. But that does not deter the epidemiologist. This “poor diet” link, using “comparative risk assessment models,” estimates that 45% of cardiometabolic disease (CMD) deaths were “associated with” 10 dietary factors, and that these factors have “‘probable or convincing evidence’ for causality” (my emphasis). Epidemiologists are shameless in their reckless disregard for a basic tenet of the scientific method: Correlation does not imply causation.

The “10 dietary [death] factors” ranged in descending order from a high of 9.5% for 1) salt (“excess sodium”), to 2) low intake of nuts/seeds, 3) high intake of processed meats, 4) low seafood omega-3 fats, 5) low intake of vegetables, 6) low intake of fruits, 7) high sugar-sweetened beverages, 8) low intake of whole grains, 9) low intake of polyunsaturated fats and finally, at 0.4%, to 10) high intake of unprocessed red meats. Hmmm… Zero point four percent does not strike me as statistically significant, but I guess they just had to include red meat.

We can also be grateful that a low intake of polyunsaturated fats (corn oil, soybean oil, etc.), at 2.3%, ranked only 8^th on the list. A higher intake, AS THEY ADVOCATE, would, IMHO, only have RAISED THE RISK OF DEATH GREATLY.

This is what your doctor, if (s)he was not on the golf course, is learning and says when (s)he say they know about nutrition. To relieve “information overload,” Tufts gives these talking points from the “know what advice to give” link.

●        Choose foods with a wide variety of colors and textures, in their most natural forms. [check]

●        Avoid or dramatically minimize processed foods. [check]

●        Choose realistic, balanced [not low-carb] diets for weight loss and weight maintenance.

●        Consume healthy oils for heart health: fish, olive, avocado. [good, all MONOs, no mention of soybean or corn]

●        Forego red meat [saturated fat and cholesterol] and live longer [a little editorializing? They just couldn’t resist!].

●        Consume fermented foods/probiotics and fiber for gastrointestinal and overall health. [check]

This is just a plant-based, one-size-fits-all, Mediterranean diet that the Dietary Guidelines recommends for everyone.  It doesn’t mention carbs or Type 2 diabetes, or any of the myriad metabolic conditions that plague the majority of the population. For them (us), balanced is just wrong, and avoiding excessive carbs and polyunsaturated fats needs to be stressed. And I would rather embrace carnivory than give up red meat for the claimed 0.4% increase in CMD death.