Recently a group of 11 senior doctors in the United Kingdom have publicly called for a dietary approach to fighting dementia. The group, consisting of a combination of specialists and primary care doctors, wrote a letter and sent it to British prime minister David Cameron and health secretary Jeremy Hunt suggesting the most powerful weapon in fighting the devastating effects of dementia is a diet rich in plants and low in animal foods. As quoted in the National Post (link), the doctors contend, “We are not going to overcome the increasing burden of chronic diseases by prescribing more pills.” They advocate for a Mediterranean diet instead of relying on the “dubious benefit of most drugs”. (link)
A recent review found a growing body of literature showing decreased risk of cognitive impairment and Alzheimer’s dementia with greater adherence to plant-based diets1. It’s nice to see top physicians suggesting food over pills and taking it to the press.
On the flip side, a ‘POEM Research Summary’ email recently disturbed me when it appeared in my inbox. POEM stands for Patient Oriented Evidence that Matters. The POEM email is usually a descriptive headline with a brief paragraph of information summarizing a recent journal article for the busy, practicing physician. For many practicing physicians, daily POEMs are a nice way to be alerted to important articles or larger shifts in thought regarding certain treatments, diagnostic tools, etc… They theoretically highlight the most relevant, most important findings in the literature.
Imagine my surprise when I got an email POEM with the title “Lifestyle changes do not affect outcomes in patients with pre-diabetes or diabetes.” Realize that whatever anyone says after this headline can never undo its damage. Huge volumes of information and tasks on a daily basis bombard practicing physicians and I would guess that the vast majority of physicians who saw this headline let the headline influence them and moved on without further thought. I can only guess how many physicians this reached. Tens of thousands? Each of who may provide care for a couple thousand patients? It likely reinforced any biases that exist against lifestyle treatment and nutrition or at least dampened the physicians’ enthusiasm.
The headline references a recent meta-analysis published in the Annals of Internal Medicine2. The paper only included studies in its consideration that were randomized controlled trials (RCT) of multifaceted interventions, including exercise, diet, and at least one other component. In all, nine studies of people at risk for diabetes were included and 11 studies of diabetics were included. Of these, only two RCTs reported data on all-cause mortality on diabetic patients taking part in lifestyle interventions, so the amount of data being used to answer their questions was astoundingly limited when considered in the context of all diet and diabetes research. The whole exercise is a perfect example of how good, rigorous scientific technique often translates into being as myopic as possible. The risk of death among those diabetic patients in the lifestyle groups trended in the right direction (they had 25% less chance of death), but the result was just shy of statistical significance.
The conclusion in the abstract of the paper2 was, “Comprehensive lifestyle interventions effectively decrease the incidence of type 2 diabetes in high-risk patients. In patients who already have type 2 diabetes, there is no evidence of reduced all-cause mortality and insufficient evidence to suggest benefit on cardiovascular and microvascular outcomes [my emphasis].” In other words, diet and lifestyle don’t matter for diabetics with regard to outcomes like heart disease, kidney disease, eye health. Using this conclusion various ‘reviewers’ and ‘summarizers’ of research papers, like the daily POEM email service, blasted the headline results to medical professionals around the country.
What a shame that we now have a way of doing research that can effectively ignore 80 years of observational data showing a profound impact of diet on diabetes, heart disease, and obesity. What a shame we can effectively ignore all the information from nonrandomized intervention research showing reversal of diabetes and heart disease and their risk factors, including high cholesterol and hypertension, simply because it does not fit the inclusion criteria. What a shame we can ignore animal studies showing biological mechanisms of action by which food dramatically affects our metabolic health. We now can publish research trumpeting grandiose sounding conclusions based on an extremely limited amount of randomized clinical trial data; RCTs that never effectively tested anything remotely similar to a whole-food, plant-based diet. This approach has almost become the gold standard of scientific review.
Unfortunately, doctors around the country, working with many thousands of diabetic patients, are collectively being told that diet and exercise don’t matter. I’m optimistic that this is just a bump in the road but it’s a good example of confusion among scientific and medical professionals that will do harm to patients.
Thomas M. Campbell, MD is the executive director of the T. Colin Campbell Center for Nutrition Studies.
- Lourida I, Soni M, Thompson-Coon J, et al. Mediterranean diet, cognitive function, and dementia: a systematic review. Epidemiology 2013;24:479-89.
- Schellenberg ES, Dryden DM, Vandermeer B, Ha C, Korownyk C. Lifestyle interventions for patients with and at risk for type 2 diabetes: a systematic review and meta-analysis. Annals of internal medicine 2013;159:543-51.