Aging gracefully: Overall quality of diet, not specific nutrients, is key, study says

22 Aug 2018 --- Eating a diet that is rich in fruits, vegetables and whole grains and low in added sugar, sodium and processed meats can help promote healthy cellular aging in women, according to researchers at the University of Michigan School of Public Health.

“The key takeaway is that following a healthy diet can help us maintain healthy cells and avoid certain chronic diseases,” says lead author Cindy Leung, Assistant Professor of Nutritional Sciences at the University of Michigan School of Public Health. “Emphasis should be placed on improving the overall quality of your diet rather than emphasizing individual foods or nutrients.”

In the study, published in the American Journal of Epidemiology, researchers used telomere length to measure cellular aging. Telomeres are DNA protein structures located on the ends of chromosomes that promote stability and protect DNA. Age is the strongest predictor of telomere length – telomeres shorten in length during each cell cycle.

However, recent studies have shown that telomeres can also be shortened due to behavioral, environmental and psychological factors. Shorter telomeres have been associated with an increased risk for heart disease, Type 2 diabetes and some cancers.

Leung and colleagues examined the diets of a nationally representative sample of nearly 5,000 healthy adults and how well they scored on four evidence-based diet quality indices, including the Mediterranean diet, the DASH diet and two commonly used measures of diet quality developed by the U.S. Department of Agriculture and the Harvard T.H. Chan School of Public Health.

For women, higher scores on each of the indices were significantly associated with longer telomere length.

“We were surprised that the findings were consistent regardless of the diet quality index we used,” says Leung. “All four diets emphasize eating plenty of fruits, vegetables, whole grains and plant-based protein and limiting consumption of sugar, sodium and red and processed meat.”

“Overall, the findings suggest that following these guidelines is associated with longer telomere length and reduces the risk of major chronic disease.”

Essentially, all of the diets are antioxidant and anti-inflammatory diets and create biochemical environments favorable to telomeres, adds co-author Elissa Eppel, Professor of Psychiatry at the University of California, San Francisco.

Interestingly, in men, the findings were in the same direction but nowhere as near as statistically significant. “We have seen some gender differences in previous nutrition and telomere studies," Leung says. “In our study, as well as in previous studies, men tended to have lower diet quality scores than women. Men also had higher intakes of sugary beverages and processed meats, both of which have been associated with shorter telomeres in prior studies.”

“It's possible that not all foods affect telomere length equally and you need higher amounts of protective foods to negate the harmful effects of others. However, more research is needed to explore this further.”

A recent study published in The Lancet Public Health similarly identified the importance of diet for a healthy life, stating that following a low-carb diet could shorten life expectancy by four years, with the replacement of carbohydrates with animal proteins and fats being particularly detrimental to health and longevity. While an International Food Information Council (IFIC) study found that the over 50s in the US are increasingly concerned with health and use nutrition and food to manage or prevent chronic disease. The study also noted, however, that there is a broad lack of understanding on how to achieve these health-based goals.