A study of 25,315 women followed for 25 years shows that greater adherence to the Mediterranean diet is associated with a 23% reduction in the risk of premature mortality, mainly from cancers and cardiovascular diseases.
The Mediterranean diet is a diversified diet, characterized by a high intake of plants (nuts, seeds, fruits, vegetables, whole grains, legumes) and extra virgin olive oil.
Fish, poultry, fermented dairy products (yogurt, cheese), eggs and alcohol (mainly in the form of red wine with meals) are consumed moderately, while the intake of red meats, sweets and Processed foods are minimal. It really is an exemplary diet, easy to adopt, and which has several positive repercussions on health.
For example, a review of 495 meta-analyses of observational studies and randomized clinical trials showed that of all dietary patterns, the Mediterranean diet has the most positive impacts on risk factors for chronic diseases such as obesity, hypertension, lipid profile (LDL, HDL, triglycerides) and maintaining normal blood sugar levels (1).
Mediterranean score
To examine whether these metabolic benefits translated into a reduced risk of premature mortality, Harvard University researchers followed more than 25,000 healthy women for 25 years and correlated their adherence to the Mediterranean diet with the incidence of all-cause mortality and, more specifically, that linked to cancer and cardiovascular diseases (2).
This adherence is expressed in the form of a score varying from 0 to 9, with higher scores representing better adherence to the 9 main components of the Mediterranean diet.
For example, above-average consumption of vegetables, fruits, nuts, whole grains, legumes, fish and olive oil were each worth one point. Below average consumption of red meat and cold meats also earned 1 point.
In addition, participants received 1 point if their daily alcohol consumption was between 5 and 15 g/day, the equivalent of a glass of wine (no points were awarded if consumption was less or more than this quantity). These scores made it possible to classify the participants into 3 groups, namely those whose adherence to the characteristics of the Mediterranean diet was low (score 0 to 3), intermediate (score 4 to 5) or high (6 to 9).
Mortality reduction
The results of the study are quite spectacular: compared to the group which adhered the least to the components of the Mediterranean diet (score 0-3), the risk of mortality from any cause is reduced by 16% for intermediate scores (4-5) and by 23% for the highest scores (6-9). These reductions appear mainly to be caused by a reduction in the risk of mortality from cancer (20% drop) and cardiovascular disease (17% drop) for scores >6.
An analysis of several biochemical markers present in the participants’ blood as well as their anthropometric parameters (weight, in particular) revealed that the reductions in mortality risk were mainly due to a reduction in the levels of biomarkers of inflammation (the protein C reactive, for example) and certain amino acids such as homocysteine and alanine, known to increase the risk of cardiovascular disease.
These two factors alone contribute 30% to the association observed between the reduction in mortality risk and adherence to the Mediterranean diet observed in the study. The reduction in BMI (10%) and the absence of insulin resistance (7%) also play an important role in the reduction in mortality associated with this diet.
Do not demonize alcohol in moderation
Some may have been surprised to see that moderate alcohol consumption is considered in the study as a positive factor, which increases the score of adherence to the Mediterranean diet.
There has in fact been a lot of talk in recent years about certain pressure groups of dubious scientific credibility, who question the benefits of low-dose alcohol in reducing mortality, even suggesting that there is no no safe alcohol consumption. This extremist, ideological and unscientific position really does not correspond to the sum of observations carried out over the last 50 years which have clearly shown that moderate consumption of alcohol, especially if it is in the form of red wine, is part of lifestyle factors leading to a significant reduction in the risk of premature mortality. Certain phytochemical molecules present in the grape skin which is preserved during the fermentation of red wine have, in fact, remarkable properties for human health.
For example, it has recently been shown that when combined with a healthy diet, regular physical activity and body weight control, moderate alcohol intake is among the factors associated with a dramatic increase (14 years) in life expectancy (3). A reduced risk of dementia in moderate alcohol drinkers has also been reported (4).
As part of an overall healthy lifestyle, including a Mediterranean-type diet for example, moderate consumption of red wine (1 glass for women, 1-2 glasses for men) therefore seems to contribute to an increase in healthy life expectancy.
(1) Dinu M et al. Effects of popular diets on anthropometric and cardiometabolic parameters: an umbrella review of meta-analyses of randomized controlled trials. Adv Nutr. 2020;11:815-833.
(2) Ahmad S et al. Mediterranean diet adherence and risk of all-cause mortality in women. JAMA Network Open 2024; 7:e2414322.
(3) Li Y et al. Impact of healthy lifestyle factors on life expectations in the US population. Traffic 2018; 138:345-355.
(4) Jeon KH et al. Changes in alcohol consumption and risk of dementia in a nationwide cohort in South Korea.. JAMA Netw Open 2023; 6: e2254771.
