They found that the diet was associated with longer telomeres, the protective structures at the end of chromosomes. Image copyright SPL Image caption Telomeres cap the end of our chromosomes 
 
 As we age and our cells divide, our telomeres get shorter - their structural integrity weakens, which can tell cells to stop dividing and die. 7 Telomeres prevent the loss of genomic DNA at the ends of linear chromosomes and in turn protect their physical integrity. 10 11 Telomere length is considered to be a biomarker of aging; shorter telomeres are associated with a decreased life expectancy and increased rates of developing age related chronic diseases. The study, published in the journal BMJ, controlled for body mass index, smoking, physical activity, reproductive history and other factors, and found that the higher the score for adherence to the diet, the longer the telomeres. As expected, women with the highest Alternate Mediterranean Diet score also had higher intakes of vegetables, fruits, grains, fish, legumes, nuts, and total fat, as well as lower meat intake. Discussion 
 
 In this large cross sectional study of 4676 healthy middle aged and older women from the well characterized Nurses’ Health Study, greater adherence to the Mediterranean diet was significantly associated with longer leukocyte telomere length. The difference in telomere length for each point on the adherence scale, the researchers estimate, was equivalent to an average one and a half years of life. The benefits on health and aging from a greater adherence to the Mediterranean diet have been largely described.
– A new study finds that following the Mediterranean diet could add about 4.5 years to your life. Researchers found that the diet, which focuses on fruits, veggies, whole grains, and olive oil, is good for our DNA, the New York Times reports. Nearly 4,700 women were followed for more than 20 years, and those whose diets were more similar to the Mediterranean diet had longer telomeres—protective structures found on the ends of chromosomes that "are often compared to the plastic caps that prevent shoelaces from unravelling," as Larry Husten explains at Forbes. Shorter telomeres have been linked to shorter life expectancy and chronic diseases associated with aging. Chromosomes store our DNA code, and telomeres help to prevent the loss of genetic information—so the Mediterranean diet appears to "stop our DNA code from scrambling as we age," thus keeping us "genetically younger," writes Michelle Roberts at the BBC. But Husten cautions that, though the diet has been linked to other health benefits in the past, this study shouldn't be given too much weight. It appears to be "excellent" and "well-performed," he writes, but it was an observational study, and as such has limitations—for example, it's possible that there were already genetic differences between subjects who adhered to the diet and those who didn't.