Mediterranean Diet - Health Effects

Health Effects

A number of diets have received attention, but the strongest evidence for a beneficial health effect and decreased mortality after switching to a largely plant based diet comes from studies of Mediterranean diet, e.g. from the NIH-AARP Diet and Health Study.

The Mediterranean diet is often cited as beneficial for being low in saturated fat and high in monounsaturated fat and dietary fiber. One of the main explanations is thought to be the health effects of olive oil included in the Mediterranean diet.

The Mediterranean diet is high in salt content. Foods such as olives, salt-cured cheeses, anchovies, capers, salted fish roe, and salads dressed with extra virgin olive oil all contain high levels of salt.

The inclusion of red wine is considered a factor contributing to health as it contains flavonoids with powerful antioxidant properties.

Mireille Guiliano credits the health effects of the Mediterranean diet to factors such as small portions, daily exercise, and the emphasis on freshness, balance, and pleasure in food.

Dietary factors are only part of the reason for the health benefits enjoyed by certain Mediterranean cultures. A healthy lifestyle (notably a physically active lifestyle or labour) is also beneficial. Environment may also be involved. However, on the population level, i.e. for the population of a whole country or a region, the influence of genetics is rather minimal, because it was shown that the slowly changing habits of Mediterranean populations, from a healthy active lifestyle and Mediterranean diet to a not so healthy, less physically active lifestyle and a diet influenced by the Western pattern diet, significantly increases risk of heart disease. There is an inverse association between adherence to the Mediterranean diet and the incidence of fatal and non fatal heart disease in initially healthy middle aged adults in the Mediterranean region.

A 10-year study published in the Journal of American Medical Association (JAMA) found that adherence to a Mediterranean diet and healthful lifestyle was associated with more than a 50% lowering of early death rates.

The putative benefits of the Mediterranean diet for cardiovascular health are primarily correlative in nature; while they reflect a very real disparity in the geographic incidence of heart disease, identifying the causal determinant of this disparity has proven difficult. The most popular dietary candidate, olive oil, has been undermined by a body of experimental evidence that diets enriched in monounsaturated fats such as olive oil are not atheroprotective when compared to diets enriched in either polyunsaturated or even saturated fats. A recently emerging alternative hypothesis to the Mediterranean diet is that differential exposure to solar ultraviolet radiation accounts for the disparity in cardiovascular health between residents of Mediterranean and more northerly countries. The proposed mechanism is solar UVB-induced synthesis of Vitamin D in the oils of the skin, which has been observed to reduce the incidence of coronary heart disease, and which rapidly diminishes with increasing latitude. Interestingly, residents of the Mediterranean are also observed to have very low rates of skin cancer (which is widely believed to be caused by over-exposure to solar UV radiation); incidence of melanomas in the Mediterranean countries is lower than in Northern Europe and significantly lower than in other hot countries such as Australia and New Zealand. Its been hypothesized that some components of the Mediterranean diet may provide protection against skin cancer.

A study published in the Archives of General Psychiatry shows that people who followed the Mediterranean diet were less likely to develop depression.