October 12, 2023—Eating a Mediterranean or Green Mediterranean diet rich in polyphenols—micronutrients found in plant-based foods and beverages such as green tea and Mankai—is associated with slower biological aging, according to a new clinical trial performed in Israel and study co-authored by researchers at Harvard T.H. Chan School of Public Health.
The study was published on September 25 in BMC Medicine. Co-authors included Frank Hu, professor of nutrition and epidemiology and chair of the Department of Nutrition; Iris Shai, principal investigator of the trial and adjunct professor of nutrition; and several members of the Department of Epidemiology: Anat Yaskolka Meir, postdoctoral research fellow and first author of the study; Meir Stampfer, research professor; and Liming Liang, professor of statistical genetics. Other co-authors were from Ben-Gurion University in Israel and Leipzig University in Germany.
Recent research has pointed to specific health benefits of polyphenols, but no studies have been conducted on their effects on biological aging—the aging of the body’s cells and tissues, apart from chronological aging. To fill this gap, researchers in Israel conducted an 18-month randomized controlled trial in which 294 adults with abdominal obesity adhered to one of three dietary interventions: healthy dietary guidelines; a Mediterranean diet; and a Green Mediterranean diet with low consumption of meat and daily consumption of polyphenol-rich green tea and Mankai. Biological aging was assessed by examining DNA methylation, known as methylation age (mAge)—chemical changes to DNA that indicate aging in cells and tissues.
The study found that adherence to the polyphenol-rich Green Mediterranean diet was associated with an 18-month reduction in mAge. This slowing of biological aging was driven mostly by the participants’ higher intake of polyphenols. The findings also indicated the effectiveness of both Mediterranean diets, with nine months of aging “saved” among those groups.