Daniel Lubetzky

In the latest study, published in the Annals of Internal Medicine, researchers led by Dr. Hanna Bloomfield from the Minneapolis VA Medical Center analyzed data from 53 studies that investigated the health effects of the Mediterranean diet. The researchers focused their attention on clinical trials, which tend to be stronger sources of data than observational studies that look at populations and ask people about their diets. In the clinical trials, people were assigned a specific Mediterranean diet or a control diet and various health measures were recorded over time.

Overall, the analysis found that people on the Mediterranean diets had a 29% lower risk of developing heart disease than those who weren’t on the diet, a 57% lower risk of developing breast cancer and a 30% reduced risk of getting diabetes.

Bloomfield is cautious, however, about interpreting these findings to mean that the Mediterranean diet can lower risk of breast cancer. Only one randomized trial involving breast cancer was included in the analysis, so more research is needed to replicate those findings before doctors can confidently advise their patients to adopt this diet if they want to lower their risk.

“I don’t think the evidence is strong enough yet for any one health group to come out with a proclamation,” says Bloomfield. The American Heart Association and the American Cancer Society note the benefits of the Mediterranean diet and its reliance on healthy fats, but both say more research is needed on whether it can prevent or significantly lower risk of heart disease or cancer. While the data in the current study showed lower rates of heart disease, diabetes and breast cancer, they did not show an overall reduced risk of dying early among those choosing Mediterranean diets.

Though the potential benefits are still being discovered, doctors don’t find much harm in eating the Mediterranean way. In fact, the most recentDietary Recommendations for Americans advised people to eat a diet that looks more like the Mediterranean diet. Most of the components of a Mediterranean diet—like vegetables, fish and olive oil—have been linked to more health benefits than adverse effects.

The results also support the changing view on fats. For decades, the message has been to lower how much fat we eat, mainly because those fats were coming from red meat and fried foods. But healthy fats may not need such restrictions. With plant or unsaturated fats, there may be benefits to consuming more, as Bloomfield’s study suggests. More research in coming years will hopefully define exactly how much of these healthy fats are optimal.

By Alice Park