Many studies have already hailed the benefits to health and longevity of the Mediterranean diet, but few have focused on older people.
The new research has come from the I.R.C.C.S. Neuromed Mediterranean Neurological Institute in Italy and comprises two parts.
The first is a study that followed 5,200 people aged 65 and older for approximately 8 years.
The second is an analysis that added data from several other studies, bringing the total of older individuals evaluated to 12,000.
In a paper on the findings that now features in the British Journal of Nutrition, the researchers describe how they found that the seniors whose food intake most closely matched a Mediterranean diet lived the longest.
First study author Marialaura Bonaccio, an epidemiologist at I.R.C.C.S. Neuromed, explains that while they knew "that the Mediterranean diet is able to reduce the risk of mortality in the general population," they did not know whether this might also be the case for older people "specifically."
She and her colleagues also observed that there was a "dose-response" relationship between diet and survival in seniors: the closer the diet was to a Mediterranean one, the longer the survival.
The findings support the idea that adopting or continuing with a Mediterranean diet could help older people "maximize their prospects for survival," they conclude.
Assessing the Mediterranean diet
Researchers started to define the Mediterranean diet in the 1960s as they compared eating habits and heart risks of people living in Greece and Southern Italy with those of individuals living in Northern Europe and the United States.
As more and more studies have been done, diverse definitions of what constitutes a Mediterranean diet have arisen. While there are some differences, they generally emphasize the following core components:
- high intake of plant foods such as leafy and other vegetables, nuts, fruits, pulses, whole cereals, and olive oil
- moderate consumption of fish, dairy, meat, and red wine
- low intake of eggs and sweets
For their investigations, Bonaccio and colleagues used a 10-point Mediterranean diet score (MDS) based on one that has been used to study Greek populations.
The MDS assesses intake of different foods and also the ratio of unsaturated to saturated fats in the diet.
An MDS of 0 means minimal adherence to a traditional Mediterranean diet, while a score of 9 means maximum adherence.
The study findings
For the first part of the study, the team analyzed the link between adherence to the Mediterranean diet and survival in 5,200 individuals aged 62 living in the Molise region in central Italy. The people had been recruited for the Moli-sani project during 2005–2010.
The purpose of the Moli-sani project was to set up a study population that was separate from those that typically feature in health studies, which tend to focus on Northern Europe and the U.S.
The scientists found that over an 8.1-year median follow-up period, for every one-point increase in MDS, there was an associated reduction in risk of death from: all causes, coronary artery disease, cerebrovascular diseases, and diseases not due to cancer or cardiovascular causes.
In the second part of the study, the scientists searched databases for other similar studies that had examined links between the Mediterranean diet and mortality in older people.
They found six studies that matched their criteria, and they added the data from those to the data they had from the Moli-sani cohort. This gave a large pool of data on 11,738 individuals.
Analysis of the pooled data showed a similar pattern to the earlier results. A one-point rise in MDS was linked to around 5 percent reduction in risk of death from all causes.
Furthermore, an analysis of pooled data from three of the studies revealed an "inverse linear dose-response relationship."
Commenting on their findings, the researchers explain that the foods that appear to offer the most protection in the Mediterranean diet are higher intakes of monounsaturated fats, such as in virgin olive oil, and "moderate consumption of alcohol, preferably during meals."
Bonaccio remarks that while they considered "nutrition as a whole," it was interesting to see the foods that "contribute to the 'driving' effect of the Mediterranean diet."
"Our data confirm what has already been observed in numerous epidemiological and metabolic studies, namely that a moderate consumption of alcoholic beverages, if inserted in a Mediterranean food context, is a protective factor for our health."