#076 - The Meat Controversy and Why Nutrition Research Is Hard - Michael Hull

humanOS Radio

All of us have heard the aphorism, “Let food be thy medicine, and medicine be thy food.” This maxim, of course, is usually attributed to ancient Greek physician Hippocrates. However, if you’ve ever spent time looking at health-related content on Twitter and Instagram, you’ll realize that conflating diet and medicine is a modern phenomenon. We like to think of certain foods and combinations of foods as exerting drug-like effects. And as we unveil the functional properties of natural compounds in edible plants - like flavonoids, just as one example - it’s easy for the lines between pharmacology and nutrition to become blurred. But food is not a drug. And the distinction between the two becomes plain when we look at what happens when scientists try to elucidate the effects of dietary exposures on health outcomes. To illustrate what I mean by this, let’s start with drugs. You probably already know that when scientists want to test a pharmaceutical intervention for safety and efficacy, the gold standard is a randomized controlled clinical trial. In this study design, participants are randomly assigned to either the substance being tested or a placebo (or usual standard of care). Neither they nor the individuals assessing their progress are told what they are taking. Now, in theory, that would be the best way to examine the effects of diet as well. But if you stop and think about it, it should be pretty clear why it simply doesn’t work the same way for nutrition. For instance, it’s really hard to measure what people are eating outside of a lab, blinding is tough to do for studies involving food, compliance for diet trials tends to be poor, and the most rigorous studies are extremely expensive. Those are just a few of the most obvious roadblocks. This mountain of ethical, financial, and practical limitations makes the field of nutrition horrendously complicated. That is why we have historically relied upon a combination of observational research (mainly prospective cohort studies), randomized controlled trials, and mechanistic studies. But some have recently questioned the rigor of this approach, and in turn are challenging major aspects of the guidelines for nutrition and health used around the world. That brings me to our guest. On this episode of humanOS Radio, Dan talks to Michael Hull. Michael has an MSc in human nutrition from McGill University, and works as a full-time senior researcher at Examine.com. Mike writes and updates the Supplement Guides, maintains the company’s vast database of supplement studies, and blogs about various topics in the realm of health and nutrition (yep, sounds like our kind of guy). You might remember that back in October, a series of studies were published that addressed the impact of red and processed meat consumption on a number of health outcomes. Importantly, these papers did not present any new evidence on the subject. Instead, they summarized the findings of existing RCTs and observational studies, and concluded that adults should continue consuming red and processed meat at current levels of intake - an obvious contradiction of most established guidelines. This, naturally, elicited a lot of turbulence online, from all across the diet spectrum. So, who’s right? Mike wrote an excellent piece for Examine.com sorting out these studies, and was kind enough to come on the show to discuss the papers and their implications. As you’ll see, this is arguably less a discussion of the health effects of meat per se, and more about the aforementioned difficulties in performing nutrition studies and interpreting research. To learn more, check out the interview!