A reader recently commented on a blog post from over a year ago: <a Something's Greasy About Dr Esselstyn's Diet. He suggested that I take a look at some recently published research supporting the diet (and, I think, revise my previously stated opinion).
One of the links was to a series of case studies presented by Dr Esselstyn. As we know, case studies can be interesting, especially in cases of rare conditions, but are not readily generalized. As coronary artery disease (CAD) is a fairly common condition, I feel that it’s more prudent to focus on larger research studies when developing recommendations for the public.
The other link was to a study conducted by, you guessed it, Dr Esselstyn. The study followed 198 CAD patients who were counselled in plant-based nutrition for approximately 44 months. Upon follow-up it was found that 21 were non-compliant (what ever that means… more on this to follow). The remaining participants all showed significant improvement, and only one experienced a related medical incident (i.e. stroke) during those 44 months.
The biggest issue with this study is that there was no control group. There is nothing to compare the participants with. It’s entirely possible that a group, provided with all the same medical treatments and advice, minus the nutritional counselling would have fared just as well. It does seem unlikely, but without the inclusion of such a group, there is no way to be certain that the nutrition counselling (and subsequent adherence) was the reason the participants fared so well. In addition, there was no control for any potential confounding factors. The authors didn’t control for anything. That means that the success could have been due to physical activity/exercise, sleep, stress reduction, socioeconomic status, etc.
There are a few other issues I have with this research. The article states that:
Initially the intervention avoided all added oils and processed
foods that contain oils, fish, meat, fowl, dairy
products, avocado, nuts, and excess salt. Patients were also asked to avoid sugary foods
(sucrose, fructose, and drinks containing
them, refined carbohydrates, fruit juices, syrups, and molasses). Subsequently, we also
excluded caffeine and fructose
However, “We considered participants adherent if they eliminated dairy, fish,
and meat, and added oil.”
My issue with the diet prescribed by Dr Esselstyn was the lack of healthy fats. I have no issue with a vegetarian diet (yes, I’m still not convinced that oil, fish, and dairy products are unhealthy, especially for those who do not suffer from CAD) which is what the adherent participants followed. This means that they could have added nuts, seeds, nut butters, sugar, coffee, avocado, and so on, to their diets and still been adherent. A far cry from the original Esselstyn diet. In turn, I also wonder what the non-adherent participants consumed. Did they eat some fish or meat? Drink some milk? Or were they chowing down on fast food and Hungry Man dinners on the regular? Without knowing these things we shouldn’t be too quick to jump to the conclusion that the Esselstyn diet is superior to all other diets when it comes to treating CAD.
Naturally, there’s also the issue that (despite stating that the authors had no known conflicts of interest) Dr Esselstyn is the author of a number of heart health and lifestyle books that would surely take a hit in sales were research contrary to his hypothesis to be published.
Sure, this study warrants further research into the benefits of plant-based diets (and Dr Esselstyn’s very low-fat plant-based diet) for CAD patients. I’d like to see some larger studies with control groups conducted. Until then, I’ll still be cooking with oils and enjoying my guacamole.