Excess sugar consumption is known to cause weight gain and to increase the risk of chronic diseases including obesity, type 2 diabetes, dyslipidemia — an abnormal level of lipids in the bloodstream — which poses a significant risk factor for cardiovascular (CV) diseases. Now, it also appears that high sugar intake speeds up signs of aging at a cellular level.
In a first-of-its-kind study, scientists at the University of California San Francisco (UCSF) found a direct link between the intake of dietary sugar and epigenetic aging. Also known as biological aging, epigenetic aging refers to an individual’s degree of aging based on patterns of DNA methylation — a normal biological process by which methyl groups are added to the DNA molecule to change its activity but without altering the sequence. DNA methylation (DNAm) is associated with an array of factors including diet, lifestyle, genetics, and disease.
The researchers also examined the impact of a healthy diet on the epigenetic markers and found the opposite effect — a higher-quality diet slowed the signs of aging. The inverse effects on aging found in the study also appear to be independent of one another, so diet and sugar consumption needs to be evaluated in a dietary context for their effects on health and aging.
The new findings appear to fit well with studies on nutritional epidemiology which show added sugars to be related to chronic diseases such as cardiometabolic conditions and cancer and related processes such as inflammation. These chronic diseases are also linked to aging and reflect one aspect of the wear and tear on our bodies as we age.
For their study, the researchers investigated a cohort of 342 women in midlife. The participants were specifically selected as they were part of the US National Growth and Health Study (NGHS) conducted in the 1980s. The previous study examined the development of obesity in 9 and 10-year-old girls, as well as the effects of obesity on cardiovascular risk factors.The same group was then recruited again between 2015 and 2019 when all of the women had entered midlife.
To assess the role of diet and sugar on epigenetic age, researchers at UCSF first utilized a number of indices to gauge diet quality, based on how closely it adheres to the Mediterranean diet, and the US Alternative Healthy Eating Index, among the participants. Researchers then compared scores from these dietary indices to a novel epigenetic clock known as GrimAge2, which like other epigenetic clocks, relies on interpreting DNA methylation, which is a reliable indicator of epigenetic age, as these patterns in DNAm have been observed to accumulate over time.
Researchers found that a higher quality diet would slow signs of epigenetic aging, while sugar consumption would do the opposite. They also found that the effects of a healthy diet showed a far more significant response compared to sugar intake. This finding shows that it would be wiser to focus on the overall quality of the diet rather than just reducing sugars.
The study is part of a growing field known as geroscience, which seeks to understand in scientific terms how aging, disease, and biology are all related. One of the important distinctions made in this field is between chronological age and biological or epigenetic age. When you celebrate your birthday each year, that is a celebration of your chronological age; one year is the same amount of time for everyone. However, epigenetic age indicates the health of your body at a cellular level, and it does not move at the same rate for everyone.
The epigenetic age of someone who eats healthy and exercises every day may increase more slowly than someone who is sedentary and consumes high amounts of sugar. Epigenetic changes are also reversible, which means that positive changes to behavior, diet, and exercise can affect the aging process.
Epigenetic age reflects modifications of our genetic material or DNA that can result in changes in our gene and protein expression. These modifications end up turning genes on or off, which can have health implications depending on how the biological functions and physiology of our cells and systems are impacted.
In brief, the study found that sugar intake and diet quality were predictors of epigenetic aging. A healthy diet appears to slow the body’s biological ‘clock’, while consuming sugar does the opposite.
