Originally published by David L. Katz, MD, MPH, FACPM, FACP, FACLM on LinkedIn: Vegetarianism: Nutrition Science Meets Media Nonsense
We get hyberbolic headlines about nutrition studies almost every week; it’s how we roll. We can come back to the reasons why we roll that way, and who profits from it, some other time.
For now, it’s enough to note that the global spate of headlines saying things like “vegetarian diet raises risk of heart disease and cancer,” allegedly in response to a new study by scientists at Cornell, takes it to a new, absurd, stupefying level. Maybe this is all just tailor-made for April Fools’ Day. The headlines are making fools of the journalists and editors writing them, and anyone reading them. Maybe it’s all a joke. It’s certainly hard to take it seriously.
The study does not report that vegetarianism increases the risk of heart disease, cancer, or any other bad outcome. Nothing of the sort. Not even close.
The study, accessible here for the brave among you, is by some leading experts in fat metabolism at Cornell. The senior author, J. Thomas Brenna, is a friend and colleague known globally for just such expertise. I have written about Dr. Brenna’s work before.
In this instance, the team speculated that human beings might show adaptations to the fats in their diets over time. In particular, they hypothesized that vegetarian populations might display some known genetic variants that make them better at producing the fats they weren’t getting directly from their food.
So, they compared genetic markers in a population of 234 primarily vegetarian Indians, to those in 311 Americans with fairly typical diets, and found, indeed, that the Indians had a higher frequency of genetic mutations that make them good at producing the fats their diet doesn’t provide.
An example? Well, one is that vegetarians are better at converting plant-based omega-3 fat, notably one called ALA, into the long-chain omega-3’s often called “fish oil,” namely EPA and DHA. This is what the authors predicted.
How did headlines about harm emanate from this? Well, the authors also found that among those adapted to the oils and foods of a traditional vegetarian diet, the imbalances of the modern diet might be especially harmful. The study did not suggest that vegetarian diets were harmful. Rather, it showed that traditional vegetarian populations might be especially prone to the harms of the modern diet. This might help explain, for example, why ethnic Indians seem so prone to type 2 diabetes when they transition to a diet of burgers, fries, and soda.