The Mediterranean diet - involving a high intake of fruits, vegetables and fish - is associated with several health benefits.
The study, published in The BMJ, has found that the Mediterranean diet is associated with longer telomere length, considered to be a marker of slower aging.
Telomeres are DNA sequences situated at the end of chromosomes. They help to protect the physical integrity of the chromosome, preventing them from fraying, which would scramble the genetic code held within.
Telomeres naturally shorten as people age, halving during the progression from infancy to adulthood, then halving again during the onset of old age. Shortened telomeres are associated with a decreased life expectancy and increased rates of developing age-related chronic diseases.
Previous research has suggested that following the Mediterranean diet can reduce overall mortality, incidence of chronic diseases - such as major cardiovascular diseases - and increase the likelihood of healthy aging, according to background information in the study.
The Mediterranean diet is characterized by:
- High intake of vegetables, fruit, nuts, legumes, unrefined grains
- High intake of olive oil but low intake of saturated fats
- Moderately high intake of fish
- Low intake of dairy products, meat and poultry
- Regular (but moderate) intake of alcohol (wine with meals).
Lifestyle factors such as obesity and sugar-sweetened drinks have been linked to shorter-than-average telomeres, as have oxidative stress and inflammation. Key components of the Mediterranean diet - fruits, nuts and vegetables - are known for their anti-inflammatory and antioxidant effects, suggesting that they could influence telomere length in a positive way.
Mediterranean diet adherence significantly associated with longer telomeres
The researchers, led by Immaculata de Vivo from Brigham and Women's Hospital and Harvard Medical School, utilized data from the Nurses' Health Study to examine whether there was an association between adherence to the Mediterranean diet and longer telomere length.
There were 4,676 participants in the study, all healthy middle-aged women who completed detailed food questionnaires and had a blood test to determine the length of their telomeres.
Each participant was assigned a diet score ranging from 0-9 points, corresponding with how close their diet resembled the Mediterranean diet. The researchers adjusted the findings for other potential confounding factors, such as high body mass index (BMI).
They found that greater adherence to the Mediterranean diet was significantly associated with longer telomeres; a change in one point along their diet scoring scale corresponded with 1.5 years of telomere aging on average.
Importantly, none of the individual components of the diet were found to be associated with telomere length. The authors state that this finding emphasizes the importance of examining whole dietary patterns as opposed to individual dietary factors in relation to health.
Future research could examine genetic factors
The study was limited by the cross-sectional design that only saw telomere length assessed at one point in time and the use of a cohort as a sample predominantly featuring women of European ancestry.
In a linked editorial, Prof. Peter Nilsson, of Lund University in Sweden, suggests that genetic factors could explain differing telomere length, "as ancestry and cultural influences could play an important role in both how we live our lives and how lifestyle preferences such as dietary patterns are developed."
Prof. Nilsson calls for future studies to take into account the possibility of interactions between genes, diet and sex, but he describes the findings of the current study as "reassuring."
The Mediterranean diet is considered to be one of the most healthy and is recommended as an eating plan by the Dietary Guidelines for Americans. The positive association found in this new study only serves to reinforce this idea.
Previously, Medical News Today reported on a study published in the Clinical Journal of the American Society of Nephrology that found an adherence to the Mediterranean diet could lower the risk of chronic kidney disease.