If there’s a single way of eating that persists in laying claim as one of the healthiest, it’s the Mediterranean diet. Experts continue to sing the praises of eating plenty of olive oil, plant foods, fish and wine.
The number of positive studies over the years makes it hard to argue with them. And though the original paper that prompted the headlines faced criticism, the researchers still think it's one of the best diet options available.
Following a Mediterranean diet can protect against the harmful effects of air pollution, according to a 2018 study conducted by New York University. The study analyzed about 550,000 people for 17 years and factored in their level of exposure to pollution. Those who followed the Mediterranean diet compared to those who didn't had a lower risk of dying from cardiovascular disease and heart attacks.
"Air pollution is hypothesized to cause bad health effects through oxidative stress and inflammation, and the Mediterranean diet is really rich in foods that are anti-inflammatory and have antioxidants that might intervene through those avenues,” said study author Chris Lim on Time.com.
It's worth noting that the diet doesn't protect against ozone exposure. (Researchers believe that ozone exposure effects the cardiac system differently.)
Why the hits keep on coming
Researchers have been uncovering the benefits of this particular diet for years. In fact, the diet's benefits for heart health were so clear in one 2013 study that researchers ended the study early, saying it was unethical to continue.
That groundbreaking paper was retracted, however, by the New England Journal of Medicine in June 2018 because of the way the study was carried out. The authors of the original paper replaced it with a corrected one that softened its language about how the diet might prevent heart attacks and strokes, NPR notes.
A change in one high-profile paper doesn't mean that researchers have changed their stance on the diet.
"I don't know anybody who would turn around from this and say, 'Now that this has been revealed, we should all eat cotton candy and turn away from the Mediterranean diet,' " David Allison, dean of the School of Public Health at Indiana University in Bloomington, tells NPR.
Research from 2014 also supported the diet. Scientists in Boston looked at the nutritional data from 4,676 women participating in the Harvard Nurses’ Health Study — the well-known ongoing prospective cohort analysis — and discovered that those whose food choices most closely followed a Mediterranean diet had longer telomeres. Telomeres are the protective buffers on the ends of chromosomes and can be used as a biomarker of aging; the longer they are, the better.
"We know that having shorter telomeres is associated with a lower life expectancy and a greater risk of cancer, heart disease and other diseases," said study coauthor Immaculata De Vivo, an associate professor of medicine at Brigham and Women’s Hospital. "Certain lifestyle factors like obesity, sugary sodas, and smoking have been found to accelerate telomere shortening, and now our research suggests the Mediterranean diet can slow this shortening."
The key is cell aging
The Mediterranean diet isn't a specific diet plan per se, but rather eating in the traditional style of those living in Mediterranean countries. It's characterized by consuming a lot of vegetables, fruits, nuts, legumes and unrefined grains. There is plenty of olive oil, but little saturated fat; a moderate intake of fish, but little dairy, meat and poultry. And while cookies and sugar are limited, a regular but moderate dose of wine is involved.
It's thought that the antioxidants present in the favored foods protect against cell aging. While the researchers didn’t find that any specific food provided the silver bullet, they suggest that it was a combination of the components that predicted telomere length.
The researchers scored each woman’s diet according to how closely it adhered to Mediterranean components. What they found was that each one-point change in their grading system equated to an extra year and a half of life. A three-point change, the study notes, would correspond to an average 4.5 years of aging, which is comparable to the difference between smokers with non-smokers.
The researchers also concluded that women who may have veered slightly from the Mediterranean diet but who still ate a healthy diet — like eating chicken and low-fat dairy products in addition to the Mediterranean basics — also had longer telomeres than those who ate a standard American diet with red meat, saturated fats, sweets and empty calories. Those who followed the Mediterranean diet, however, had the longest telomeres on average.
Editor's note: This story was originally published in December 2014 and has been updated with more recent information.