The Mediterranean diet keeps on gathering merits: Heart disease, metabolic syndrome, cancer, and cognitive decline are some of the conditions it may prevent, or in some cases, reverse. It’s also been linked to a longer lifespan in people who stick to it over the long term. And a new study adds some intriguing evidence to the connection, finding that people who adhered to a Mediterranean-style diet had “younger”-looking chromosomes. What's more, the study was done in an American sample: Just imagine what might be the effect on Mediterranean participants.
The researchers from Harvard Medical School used data from the ongoing Nurses’ Health Study to look at connections between diet and cellular aging. They were particularly interested in a part of the chromosome called the telomere, which is considered a biomarker for aging. The region is a repetitive DNA sequence at the ends of chromosomes that prevents the DNA from “unraveling” or otherwise degrading (they’re often likened to aglets, the plastic tips at the ends of shoelaces). Each time a cell divides, the telomere shortens – so older people naturally have shorter telomeres than young people. So do people with chronic illnesses, including heart disease and some cancers.
The team found that people who ate a Mediterranean diet had longer telomeres than people who ate a “Western” diet, even when factors like body mass index, age, exercise level, calorie intake, and smoking history were controlled for.
This is not to say that eating a Mediterranean diet lengthens the telomeres – just that it prevents them from shrinking as fast.
Why would a Mediterranean diet protect the telomere from shrinking? It seems to have to do with the reduction of inflammation and oxidative stress, which are both known to speed up telomere shrinkage over time. We do things every day that contribute to oxidative stress and inflammation: Smoking, being obese, and eating a high-sugar diet are all linked to shorter telomeres. The antioxidants in the Mediterranean diet are thought to reduce inflammation and oxidative stress in our cells, possibly leading to a healthier telomere.
“Many chronic diseases, coronary heart disease in particular, are marked by inflammation,” study author Immaculata De Vivo tells me. “It’s the antioxidants – in fruits, veggies and olive oil, wine, nuts, fish – that seem to have the effect, reducing inflammation and oxidative stress. It’s the richness of diet. But it’s not lengthening the telomere, it’s just buffering it against accelerated shrinking. In other words, it keeps telomeres from shrinking faster than they should.”
There was no particular item in the diet that was linked to longer telomeres, the authors found when they separated each one out. So it’s not the wine, nuts, fish, or greens separately that has an effect, but it seems to be all of the elements in concert. The next step is to look at telomere length in an actual Mediterranean population.
“What we’d like to do,” says De Vivo, “since we looked at individual components in this population – is to do it in authentic population, like in a Greek study, with folks that have adhered to the Mediterranean diet their whole lives. To get a better sense of whether it’s a certain component… or if it’s truly the holistic diet.”
In the meantime, there’s not much reason not to try it out. The Mediterranean diet is rich in fruits, vegetables, nuts, olive oil, fish, whole grains, and usually includes a little wine with dinner; it doesn’t make much room for red meat, poultry, dairy, and sweets, though a little every now and then is probably ok.
As De Vivo says, “There’s really no downside to the Mediterranean diet. It’s been shown to have many protective health effects. And it’s delicious, too.”
