For years, the standard nutritional advice for cardiovascular disease prevention has been to follow a low-fat diet. This is still the official recommendation of the American Heart Association. However, more and more evidence is pointing to the fact that it may be the quality, not quantity, of the fats we consume that is good for our hearts.
A few weeks ago, I wrote about a new study showing that detrimental effects of red meat consumption on our gut bacteria. This could be one of the keys that links higher risk of cardiovascular disease to hiding meat intake. The Mediterranean diet, which is low in meat, has just gotten some new support for its effectiveness in primary prevention of cardiovascular disease. The Mediterranean diet is definitely not low in fat; it just relies more on different types of fat than the standard American diet (S.A.D.). Instead of high levels of animal-based saturated fats from meat and dairy, the Mediterranean approach relies more on the healthful unsaturated fats in nuts and olive oil.
This new study from Spain, called PREDIMED (1), differs from previous research, in that it was a randomized controlled trial, involving over 7000 older men and women without any established cardiovascular disease. This means that the investigators assigned a different diet to different groups of subjects — either Mediterranean, or the AHA low-fat diet. Most previous research was a retrospective — that is, it looked at people’s dietary habits in the past, based on recall or diet diaries.
The exciting finding from PREDIMED is that the Mediterranean diet, with a special focus on either olive oil or nuts, resulted in about a 30% lower risk of heart attack, stroke, or cardiovascular death compared to the low-fat approach. Perhaps surprisingly, there are no studies of similar quality to support the benefits of a low-fat diet. This recommendation of the AHA could be classified as a medical myth.
Dr Ramón Estruch, one of the lead researchers in this study, summarized his recommendations this way:
“People should know that the Mediterranean diet is a diet healthier than others and should know the key components of this food pattern. The plan should be to increase the intake of the key foods (vegetables, fruit, nuts, fish, legumes, extra virgin olive oil, and red wine in moderation), also increase the intake of white meat, and decrease the intake of red and processed meat, soda drinks, whole dairy products, commercial bakery goods, and sweets and pastries.”
He continued: “To achieve a score of 14 in the 14-item adherence scale to traditional Mediterranean diet [laid out in a supplemental appendix in the paper] is more or less impossible, but to upgrade two to three points in this score is enough to reduce your cardiovascular risk by 30%.”