A diet rich in plant foods, lean protein, and healthy fat is associated with a reduced risk of death from cardiovascular disease, cancer, and all causes; however, many of the cellular and molecular mechanisms of these relationships are unknown. One of the mechanisms that controls a person’s response to diet and risk of disease is epigenetic modification. Findings of a new investigation detail the relationship between healthy eating and epigenetic and biological age.

While a person’s genetic code does not change over time, the pattern of epigenetic markers attached to DNA does change with age. Epigenetic modifications include the addition and subtraction of methyl groups, naturally occurring processes that regulate gene expression. These changes are quantifiable and serve as a means to gauge biological age, which is often different from chronological age. Epigenetic aging clocks use an organism’s DNA methylation profile biomarker of aging based on alterations in an organism’s DNA methylation profile and can be used to predict likelihood of death (i.e., mortality).

The investigators utilized data from the Sister Study, an observational study of over 50,000 females in the United States who had a biological sister diagnosed with breast cancer, but were free from cancer themselves. These participants provided data about their dietary habits and provided a blood sample for the measurement of epigenetic age and other factors. Next, the authors analyzed the diet data and calculated four scores of diet quality that aligned with dietary recommendations from the USDA and other sources. The authors analyzed a subsample of almost 3,000 participants in order to calculate epigenetic age using the Hannum, Horvath, PhenoAge, and GrimAge clocks.

The data revealed only a weak association between higher diet quality and epigenetic age as measured by the two aging clocks designed as predictors of chronological age (Horvath and Hannum clocks). However, there was a strong relationship between diet quality and epigenetic age calculated by the two clocks designed to estimate mortality (PhenoAge and GrimAge clocks). This highlights the differences between aging clock designs, but it also supports a relationship between diet quality and disease risk that is mediated by epigenetic changes. The relationship between increased diet quality and reduced mortality-related epigenetic age was strongest among participants who did not meet exercise recommendations. Smoking status and age did not significantly alter these statistical relationships.

These findings demonstrate that higher diet quality is associated with a lower biological age as estimated by epigenetic clocks designed to predict mortality. Learn more about epigenetics from expert Dr. Steve Horvath, creator of the Horvath epigenetic aging clock, in this episode of the FoundMyFitness podcast.

• Link to full publication.

• Learn more about epigenetic aging clocks in our overview article.