Eating too much sugar may accelerate cellular aging

A nutrient-rich diet with few added sugars may slow rates of biological aging in women, new research suggests.

In a new study, published Monday (July 29) in the journal JAMA Network Open, scientists found that middle-aged women who ate more foods packed with vitamins, minerals and antioxidants had "younger-looking" cells than those who consumed less nutrient-rich diets.

They judged the youthfulness of cells by looking at chemical tags, known as methyl groups, on the surface of DNA molecules. These tags tweak the activity of specific genes without altering the underlying DNA code — a process known as epigenetic modification. The pattern of these methyl groups changes as we age, which is believed to contribute to accelerated cellular aging.

While nutrient-rich diets were tied to slowed aging, added sugars seemed to dampen the effect.

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In the study, women who consumed higher amounts of added sugars showed signs of hastened cellular aging compared to others, even if they ate an otherwise healthy diet, the researchers found. "Added sugars" refers to sugars that are added to food during production, such as those in sugar-sweetened drinks and baked goods, as opposed to the naturally occuring sugars found in milk, fruits and vegetables.

The new study is one of the first to demonstrate a link between added sugar consumption and so-called epigenetic aging, the authors said. It is also the first to investigate this association in both Black and white women in midlife, they noted. The participants were 39 years old, on average.

"We knew that high levels of added sugars are linked to worsened metabolic health and early disease, possibly more than any other dietary factor," study co-author Elissa Epel, a professor of psychiatry at the University of California, San Francisco, said in a statement.

"Now we know that accelerated epigenetic aging is underlying this relationship, and this is likely one of many ways that excessive sugar intake limits healthy longevity," she said.

Epel and colleagues analyzed food records cataloged by 342 women over three, non-consecutive days. The team then scored each woman's diet based on how closely it adhered to various established diets. These included the Mediterranean diet, which is rich in plants, whole grains and unsaturated fats and low in red meats, saturated fats and sugars. Another, similar diet, called the Alternative Healthy Eating Index, specifically emphasizes foods and nutrients believed to reduce the risk of chronic disease.

The researchers also devised a new measure of nutrient intake called the "Epigenetic Nutrient Index." This includes nutrients linked to antioxidative and anti-inflammatory processes in the body, as well as to DNA maintenance and repair. For example, it includes vitamins A, C, B12 and E, along with folate and magnesium.

In addition to scoring people's diets, the team assessed how much added sugar the women ate — which ranged between 0.1 and 11 ounces (2.7 and 316 grams) of added sugar a day. The team calculated the participants' epigenetic ages by looking at the DNA methylation of cells within saliva samples.

These data revealed the links between diet and cellular aging, but they only captured a snapshot.

The findings support the idea that eating nutritious foods that are low in added sugars may improve a person's health span, meaning the period of their life in which they are healthy, not just surviving.

However, more research is needed to assess how following these diets might affect epigenetic aging in the long run, the authors wrote in their paper.

This article is for informational purposes only and is not meant to offer medical advice.

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