If you're at risk to develop diabetes, and in these days of increasing body mass and sedentary lifestyle, who isn't? perhaps you'd prefer a switch to what's morphed into a 'Mediterranean diet,' from your normal pattern of consumption rather than hiring a former Marine as a personal trainer or going on a prolonged juice fast. That's one interpretation of a study Rick and I discuss on PodMed this week, published in Annals of Internal Medicine. And as we quip, we'd be happy to ship out to the Mediterranean to consume same as we're enduring some rather frigid weather right now on the east coast of the US, but what do investigators do in this study?
The study enrolled over 3500 men and women at risk for the development of cardiovascular disease in Spain, with this particular study representing a subgroup analysis. The study took place from October 2003 to December 2010, with an average follow up of 4.1 years. Participants were randomly assigned to one of three dietary groups: a Mediterranean diet supplemented with extra-virgin olive oil (EVOO), the same diet supplemented by nuts, and a control group who simply received dietary advice on low-fat consumption. Study subjects were also stratified with regard to age, sex, and study site. No weight loss or physical activity interventions were employed. It should be noted that the Mediterranean diet is actually fairly high in fat consumption, with about 35-40% of calories from fat, largely vegetable in origin. Dairy products are limited, and moderate alcohol consumption, particularly red wine, is typical. Tomato-based sauces and garlic figure prominently.
One of my favorite aspects of the trial was that subjects were provided with either EVOO, nuts, including hazelnuts, walnuts and almonds, or nonfood items associated with shopping or cooking, depending on which group they were assigned to. Wow! Anyone who's taken a look at the price of EVOO lately might consider that supplement a powerful inducement to entering and completing the study. All subjects met with a dietician and competed diet questionnaires at 3 month intervals. Among the many assessments performed at study enrollment was the absence of diabetes.
During the follow up period, 273 participants developed diabetes, 80 of whom were in the EVOO dietary group, 92 in the nut supplementation group, and 101 in the low-fat advice group. Crunching the numbers leads to the conclusion that the Mediterranean diet groups experienced an overall 30% reduction in their risk of developing diabetes over the study period compared with the control group, with the group consuming the EVOO faring best. There was no weight loss seen in any group, which as I comment to Rick in the podcast, calls into question the idea that increased BMI alone is the culprit when it comes to the rampant development of type 2 diabetes worldwide. Clearly this is also good news for folks who aren't willing to endure Draconian measures to either lose weight or increasing physical activity, but are willing to make chances to their diet. As we opine, however, results are no carte blanche with regard to increasing BMI, as it remains associated with many other health issues including cardiovascular disease, osteoarthritis and cancer.
Other topics this week include a novel device for overcoming obstructive sleep apnea in NEJM, and an entire issue of which we highlight two studies on cigarette smoking in JAMA. Until next week, y'all live well.