I was recently having a conversation with someone who sells health supplements regarding the veracity of clinical research. I was telling him that the conclusions reached by many applied researchers are often erroneous or at the very least incomplete due to methodology errors. It’s difficult to get a good picture of what’s happening in a human sample when one can only control several of the almost infinite number of variables that may influence the conclusions of the study. But that doesn’t stop researchers, then doctors and the press, from running with those erroneous conclusions and providing bad or incomplete information to patients and the public at large and reducing laypeople’s confidence in scientific studies.
A perfect example of this came into my inbox this morning, thanks to Mark Sisson, of Mark’s Daily Apple fame, who sends out musings on Sundays. He was unpacking a recent study that’s been talked about a lot lately from the American Journal of Clinical Nutrition. It was actually well done, as clinical trials go, but the conclusions leave us with many big questions – or should leave us with questions. The press has left us with the conclusions, “White Meat No Better Than Red Meat”, “Whether White or Red, You’ll Still Be Dead”, and “There’s No Escape: Even Chicken Kills”.
The researchers looked at the type of protein people were eating, either beef, chicken or plant protein, as well as the amount of saturated fat. Their aim was finding what was most risky for cardiovascular disease (CVD), but their measures constitute their first big flaws in the study. The biggest risk factors for CVD are now known to be triglyceride level (you make triglycerides from eating carbohydrates, which were not controlled in this study – everyone was eating a high-carb diet) and HDL level. The beef and chicken eaters had higher levels of large LDL particles, which have not been shown to impact CVD, but not higher levels of small, dense LDL, which are known to be problematic. So what can we conclude from this study? Not much, and nothing impactful.
Why would the researchers not control for carbohydrate intake, knowing the role triglycerides play in CVD? Because they went into the study thinking about how eating more meat or more saturated fat must cause CVD, and they set out to see if they were right. They set up the study to ignore the most important factor, carbohydrate intake. Anyone who is research-savvy and knowledgeable in this area, including the authors of this study, should see this huge confounding variable and not draw any conclusions until they do more research to test this. But, alas, they did not do that. So we are left with more questions at best and potentially fatal nutritional advice at worst.
From previous research in this area, we know that the effects of meat and saturated fat are dependent on the amount of carbohydrate one eats. Those on low-carb diets who eat plenty of meat and saturated fat don’t have the CVD risk factors that high-carb eaters do who also eat meat and saturated fat. Reducing the saturated fat in a high-carb eater’s diet improves some of their markers for CVD risk (e.g., cholesterol, which is no longer considered to be a risk factor, though most doctors aren’t aware of this because they don’t keep up on the latest), though some are made worse (e.g., triglycerides, HDL – now considered the most important ones). Additionally, high-carb diets are known to increase risk for (or flat-out cause) diabetes, obesity, and all related issues (joint problems, hormone imbalances, etc.), and increase symptoms of autoimmune and neurological diseases such as IBS, Crohn’s, Alzheimer’s, and Parkinson’s, among many others. Why take these risks with a high-carb, low-fat diet? Why increase triglycerides and lower HDL, giving you the highest risk for CVD, by eating a high-carb, low-fat diet? Why not just lower the carbs and lower your risk for all of these conditions?
This has been a methodological issue in many similar studies, but the medical and nutrition communities are not correcting it, so the research into these significant questions is done in fields such as bioenergetics, or the science of metabolism, which is more controlled research that gives us much more solid conclusions. And when you add in the political influence for a high-carb diet (think corn and soybean farming – if they were to fail our economy would fail), you can see how there might be a blind spot in the more publicized clinical trials. There are career-related strings attached to those trials.
We turn to science for the correct information about the way the world works. The problem is that laypeople don’t understand how science works. Not every study is proving something unequivocally, but rather is providing evidence for a theory, which may be correct or incorrect. A lot of different good studies from good labs give us the best picture of that is real and what we just want to see to get another publication or sell a product. We must pick apart the issues in our own and our peers’ studies to see what questions still must be answered to know what’s true. This isn’t always done well in one branch of research, so other researchers in other branches keep them honest. Replication of research is the name of the game, and basic and clinical research should be moving in that direction. In the field of nutrition, however, they are worlds apart and the clinical questions being raised are not being tested by the clinical research community; they are ignored. They seem more interested in finding evidence for their current low-fat, high-carb, plant-based dogma than answering the questions that are coming out of their research. Politics infests everything, including science. Thankfully, science has checks and balances, so we’ll eventually get to the truth. Until then we have to take what we hear with a grain of salt until we analyze the actual studies or look to people we trust to do that for us.