Latest scientific news 10 April 2015

Is moderate consumption of alcoholic beverages the most important aspect of the Mediterranean Diet?

An Italian study investigating the contribution of a Mediterranean-type diet and its components adds more evidence that such an eating pattern can reduce the mortality risk among diabetics. Among various components such as a high consumption of cereals, fruits and nuts, the moderate intake of alcoholic beverages/wine was a major protective factor.

The “Mediterranean Diet” (MD) is reputed for its beneficial health effects in the nutrition field. This dietary pattern refers to the traditional way of eating by Mediterranean populations in the early 1960s. It is characterized by abundant use of olive oil, high consumption of plant foods (fruits, vegetables, legumes, cereals, nuts, and seeds), frequent but moderate intake of wine with meals, moderate consumption of fish, seafood, fermented dairy products (yogurt and cheese), poultry, and eggs and low consumption of red and processed meat and sweets.

In numerous studies, adherence to the Mediterranean diet was associated with lower mortality in the general population. The epidemiological evidence is particularly strong for the preventive effects of the MD on cardiovascular disease (CVD). In fact, some experts consider the MD the most likely dietary model to provide causal CVD-protection as there is high biological plausibility for this effect. In addition, the MD has been associated with a reduced incidence of diabetes. But so far, only limited evidence exists on the effect of a Mediterranean diet on mortality in diabetic individuals.

Recently, several Italian researchers examined whether greater adherence to the traditional MD in a Mediterranean region such as Southern Italy, could reduce overall and/or cardiovascular mortality in individuals with type-2-diabetes. In addition, they investigated the contribution of single dietary components to the overall effect of the MD in relation to mortality.  A prospective cohort study with 1995 type-2 diabetic subjects recruited within the MOLI-SANI study to examine these associations was carried out. The food intake of the participants was recorded by a validated food frequency questionnaire and adherence to the traditional MD was estimated by using the Mediterranean Diet Score developed by the famous Greek scientist Antonia Trichopoulou.

During an average follow-up of 4 years, 109 deaths due to miscellaneous causes occurred, including 51 cardiovascular deaths. The researchers observed that a 2-unit increase in the Mediterranean diet score was associated with 37% lower overall mortality. A reduction of 34 % was observed when cardiovascular mortality only was considered.

When the scientists calculated the relative contribution of the MD to the effect for each dietary component, the results showed that the greatest protective effect derived from moderate drinking of alcoholic beverages (14.7 %) followed by a high intake of cereals, monounsaturated fatty acids, vegetables and fruits and nuts (12.2 %, 5.8 %, 5.8 % and 5.2 %, respectively).

Thus, based on the results of this study, the traditional Mediterranean diet was associated with reduced risk of both total and cardiovascular mortality in diabetic subjects, independently of the severity of the disease. The major contributions of this protective effect were offered by moderate intake of alcoholic beverages, followed by the broadly accepted “healthy foods” like cereals, fruits and nuts.

Bonaccio M, Di Castelnuovo A, Costanzo S, et al; on behalf of the MOLI-SANI study Investigators. Adherence to the traditional Mediterranean diet and mortality in subjects with diabetes. Prospective results from the MOLI-SANI study. Eur J Prev Cardiol. 2015 Feb 3. [Epub ahead of print]

For more information about this article, read the scientific abstract here.