Field Notes

Healthful Diet With Less Sugar Is Linked to Younger Biological Age

Researchers at the University of California, San Francisco (UCSF) have found a link between following a diet that’s rich in vitamins and minerals, especially one without much added sugar, and having a younger biological age at the cellular level.

They looked at how three different measures of healthful eating affected an “epigenetic clock”—a biochemical test that can approximate both health and lifespan—and found that the better people ate, the younger their cells looked. Even when people ate healthful diets, each gram of added sugar they consumed was associated with an increase in their epigenetic age

“The diets we examined align with existing recommendations for preventing disease and promoting health, and they highlight the potency of antioxidant and anti-inflammatory nutrients in particular,” explains Dorothy Chiu, PhD, a postdoctoral scholar at the UCSF Osher Center for Integrative Health and first author of the study. “From a lifestyle medicine standpoint, it’s empowering to see how heeding these recommendations may promote a younger cellular age relative to chronological age.”

The study is one of the first to show a link between added sugar and epigenetic aging and the first to examine this link in a heterogenous group of women—both Black and white—in midlife. Most studies on the topic have involved older white participants.

The study helps deepen our understanding of why too much sugar is so detrimental to health, adds study cosenior author Elissa Epel, PhD, a UCSF professor in the department of psychiatry and behavioral sciences.

“We knew that high levels of added sugars are linked to worsened metabolic health and early disease, possibly more than any other dietary factor,” Epel says. “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.”

Women in the study reported consuming an average of 61.5 g of added sugar per day, though the range was large: from 2.7 to 316 g of added sugar daily. A bar of milk chocolate has about 25 g of added sugar, while a 12-oz can of cola has about 39 g. The FDA recommends adults consume no more than 50 g of added sugar per day.

A Nutrient-Based Approach 
For the cross-sectional study, researchers analyzed food records from 342 Black and white women with a mean age of 39 years from Northern California. Then, they compared their diets with epigenetic clock measures, which were derived from saliva samples.

Researchers scored the women’s diets to see how they compared with a Mediterranean-style diet rich in anti-inflammatory and antioxidant foods and then with a diet linked to lower risk for chronic disease.

Finally, they scored the women’s diets against a measure they created called the “Epigenetic Nutrient Index,” which is based on nutrients (not foods) that have been linked to antioxidative or anti-inflammatory processes and DNA maintenance and repair. These include vitamins A, C, B12, and E, folate, selenium, magnesium, dietary fiber, and isoflavones.

Adherence to any of the diets was significantly associated with lower epigenetic age, with the Mediterranean diet having the strongest association.

The researchers examined sugar intake separately and found that consuming foods with added sugar was associated with accelerated biological aging, even in the presence of an otherwise healthful diet.

“Given that epigenetic patterns appear to be reversible, it may be that eliminating 10 grams of added sugar per day is akin to turning back the biological clock by 2.4 months if sustained over time,” says cosenior author Barbara Laraia, PhD, RD, a University of California, Berkeley professor in the Food, Nutrition and Population Health program. “Focusing on foods that are high in key nutrients and low in added sugars may be a new way to help motivate people to eat well for longevity.”

— Source: University of California, San Francisco

 

Boosting Fruit Intake During Midlife Can Ward Off Late-Life Blues

Populations are rapidly aging worldwide, and there is an increased prevalence of late-life depressive symptoms among older adults, which include depressed feelings, lack of pleasure, delayed cognitive processing, and reduced volitional activity, often accompanied by loss of appetite, insomnia, poor concentration, and increased fatigue. This has been related to underlying neurodegenerative changes in the brain associated with aging.

The growing imperative to keep older adults in good health has spurred extensive research into approaches that could prevent late-life depression, and accumulating evidence has revealed the plausible role of dietary factors in protecting against depression in aging. Could specific diet or food items consumed earlier in life have an impact on mental well-being in later years?

In a longitudinal study conducted by the Yong Loo Lin School of Medicine at the National University of Singapore (NUS Medicine), involving 13,738 participants from the large population-based Singapore Chinese Health Study that tracked participants through their midlife to later life spanning about 20 years, researchers found that participants who consumed higher quantities of fruits earlier in life exhibited a reduced likelihood of experiencing depressive symptoms later in life.

The authors studied a total of 14 fruits most commonly consumed in Singapore and found that the consumption of most fruits, including oranges, tangerines, bananas, papayas, watermelons, apples, and honey melons, was associated with reduced likelihood of depression. The association could possibly be the high levels of antioxidants and anti-inflammatory micronutrients in fruits—such as vitamin C, carotenoids, and flavonoids—which have been shown to reduce oxidative stress and inhibit inflammatory processes in the body that may affect the development of depression.

Consumption of vegetables, on the other hand, was found to have no association with the likelihood of depressive symptoms. The findings, published in the Journal of Nutrition, Health and Aging, provide valuable insights into the potential benefits of eating sufficient fruits in mitigating depressive symptoms later in life.

Koh Woon Puay, PhD, from the Healthy Longevity Translational Research Programme at NUS Medicine and principal investigator of the study, explains, "Our study underscores the importance of fruit consumption as a preventive measure against aging-related depression. In our study population, participants who had at least three servings of fruits a day, compared with those with less than one serving a day, were able to reduce the likelihood of aging-related depression significantly by at least 21%. This can be achieved by eating one to two servings of fruits after every meal.

We didn’t see any difference in our results between fruits with high and low glycemic index. Hence, for those with diabetes, they can choose fruits with low glycemic index that will not raise blood sugars as much as those with high index."

At the initial stage of the study from 1993 to 1998, when participants were of an average age of 51 years, they were asked to answer a structured questionnaire on how often they consumed a standard serving size of each food item daily for 14 fruits and 25 vegetables.

From 2014 to 2016, when participants were of the average age of 73 years, depressive symptoms were examined using a standard test (Geriatric Depression Scale), and 3,180 (23.1%) participants who reported having five or more symptoms were considered to have depression in the study. After adjusting for factors that could potentially confound the relationship, including medical history, smoking status, level of physical activity, sleep duration, and aging-related factors, the team found that higher consumption of fruits, but not vegetables, was associated with lower odds of depressive symptoms in a stepwise manner.

Koh adds, "Our study aimed to examine the relationship of midlife consumption of fruits and vegetables with the risk of depressive symptoms in late life. Although other studies have also examined the associations of fruits and vegetables with the risk of depression, there are inconsistencies in the results, and many of them were done in Western populations. To our best knowledge, ours is the largest population-based study in an Asian population to study this association."

These findings suggest that promoting fruit consumption for individuals in midadulthood, typically defined as ages 40 to 65 years, could yield long-term benefits for their mental well-being in late adulthood beyond 65 years. Hence, the study's results hold significant implications for public health education and initiatives to make fruits more accessible to the general population. Following the study, the research team is looking into the association of other modifiable behavioral factors, such as sleep duration, smoking, and other dietary factors, with the mental health of older adults.

— Source: National University of Singapore, Yong Loo Lin School of Medicine