Eating a diet that is rich in fruits, vegetables and whole grains and low in added sugar, sodium and processed meats could help promote healthy cellular ageing in women, a study has found. "The key takeaway is that following a healthy diet can help us maintain healthy cells and avoid certain chronic diseases," said 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 emphasising individual foods or nutrients."
In the study, researchers used telomere length to measure cellular ageing. 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 behavioural, 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 US Department of Agriculture and the Harvard TH 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," Leung said. "All four diets emphasise 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."
Co-author Elissa Epel, professor of psychiatry at the University of California – San Francisco, said "the commonality to all of the healthy diet patterns is that they are antioxidant and anti-inflammatory diets. They create a biochemical environment favourable to telomeres."
In men, the findings were in the same direction, but not statistically significant. "We have seen some gender differences in previous nutrition and telomere studies," Leung said. "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 in order to negate the harmful effects of others. However, more research is needed to explore this further."
Aging is the biggest risk factor for the development of chronic diseases. Telomere length may represent one important mechanism by which dietary intake influences age-related diseases; however, it is unknown which diet pattern is most strongly related to telomere length. We compared the relations between four evidence-based diet quality indices and leukocyte telomere length in a nationally representative sample of healthy adults, and the extent to which these associations differ between men and women. Data came from 4,758 adults, aged 20-65 years, with no prior diagnosis of major chronic disease, from the 1999-2002 National Health and Nutrition Examination Surveys (NHANES). Diet was assessed using one 24-hour dietary recall. After adjusting for sociodemographic and health characteristics, comparing the top and bottom quintiles showed that higher Healthy Eating Index-2010 (β=0.065, 95% CI 0.018, 0.112, P-trend=0.007), AHEI-2010 scores (β=0.054, 95% CI 0.010, 0.097, P-trend=0.007), Mediterranean Diet scores (β=0.058, 95% CI 0.017, 0.098, P-trend=0.008), and Dietary Approaches to Stopping Hypertension (DASH) scores (β=0.052, 95% CI 0.014, 0.090, P-trend=0.007) were each associated with longer telomere length in women. These results may provide insight into the complex associations between optimal nutrition and longevity. Further investigation is needed to understand why associations were not observed in men.
Cindy W Leung, Teresa T Fung, Claire T McEvoy, Jue Lin, Elissa S Epel
[link url="https://www.sciencedaily.com/releases/2018/08/180820164248.htm"]University of Michigan material[/link]
[link url="https://academic.oup.com/aje/advance-article-abstract/doi/10.1093/aje/kwy124/5038505?redirectedFrom=fulltext"]American Journal of Epidemiology abstract[/link]