This Common Ingredient Could Accelerate Aging, New Study Reveals

A diet high in added sugar may make cells age faster, according to recent research published in JAMA Network Open.

More than half of American adults eat more than the recommended amount of daily sugar. It’s well-established that eating and drinking too much added sugar—abundant in processed and ultra-processed foods—leads to health problems such as obesity and type 2 diabetes. 

But the new study found that excess added sugar may also change how cells function and lead to an accelerated biological age—the age of a person’s cells rather than how much time has passed since birth.

“Sugar is itself an inflammatory agent, as well as one that causes oxidative stress in the body,” Dorothy Chiu, PhD, a postdoctoral scholar at the Osher Center for Integrative Health at the University of California San Francisco, who co-authored the study, told Health. 

Oxidative stress occurs when free radicals outnumber antioxidants in the body, which causes cellular damage. Both oxidative stress and inflammation can speed up biological aging.

Chiu and her team analyzed data collected from the National Heart, Lung, and Blood Institute Growth and Health Study (NGHS), which took place between 1987 and 1997. 

The data included information on the cardiovascular health of a group of white and Black girls between the ages of 9 and 19. The researchers followed up with nearly 350 of those participants, all of whom were living in Northern California, between 2015 and 2019.

The women reported information about their diet and also gave saliva samples that the team used to analyze their biological age. They used a marker called GrimAge2, which provides information about disease risk and mortality.

The researchers first looked at participants’ overall diets, scoring them against a Mediterranean-style diet and an eating pattern linked to lower risk for chronic disease. They also developed scores based on a measure they created that factors in nutrients associated with anti-inflammation and DNA repair. 

They found that participants who followed the diets tended to have a lower biological age.

Then the researchers examined participant sugar intake. They discovered that, on average, the study participants consumed more than 60 grams of added sugar daily. However, the daily excess sugar they ate or drank ranged from about 3 grams to as much as 316 grams.

The Dietary Guidelines for Americans recommend that people who eat about 2,000 calories a day consume no more than 50 grams of added sugar daily—for reference, a 12-ounce can of regular Coca‑Cola contains 39 grams.

Even for people who ate a healthy diet, researchers found that consuming added sugar biologically aged their cells faster than their chronological age, meaning their cells were more likely to be biologically older than the person was in years.

In addition to factors such as activity and stress levels, the study suggests that excess sugar plays a significant role in epigenetics, which is how behaviors and the environment can cause changes that affect gene functioning.

“High amounts of sugar can affect your metabolism, and anything that affects your metabolism can affect your cellular growth,” said Julia Zumpano, RD, a registered dietitian with the Cleveland Clinic Center for Human Nutrition, who was not involved in the new study. 

Excess sugar also speeds up glycation, which occurs when sugar in the bloodstream attaches to proteins and produces harmful agents called advanced glycation end products (AGEs). These AGEs can cause inflammation and oxidative stress that speeds up cellular aging, Zumpano told Health. 

The good news is that damage sustained through epigenetic processes appears reversible, Chiu said. She and her co-authors estimated that eliminating 10 grams of added sugar per day over time would turn back a person's biological clock by about 2.4 months.

Zumpano said that it’s important that people understand the difference between sugar types. “There is a significant difference between added and natural sugars,” she said. “Natural sugars occur in fruits and starchy vegetables and rarely create an issue unless they are eaten in excess.”

While chips, desserts, and soda are well-known culprits of added sugar, Zumpano said sugar hides in foods many people wouldn’t think of, including salad dressings, frozen meals, and even supplements.

Though the Dietary Guidelines for Americans recommends limiting added sugar to 50 grams daily, Zumpano believes that even that amount is too much. She recommends consuming a maximum of 25 grams to 35 grams of added sugar daily.

“Sugar is one of the biggest concerns in the standard American diet that is leading to poor health and longevity,” Zumpano said.

Sugar is not the only dietary factor that can cause harm, but eating more sugar-dense foods can also make a person eat less nutrient-dense foods, “which results in a bit of a double-whammy, epigenetically, on the body,” Chiu said.

If someone wants to cut more sugar out of their diet, Zumpano recommends “beginning with your ‘heavy hitters.’”

First, replace sweetened beverages with water, she said. Next, cut back on other obvious added sugar sources like sweets, desserts, and baked goods. Finally, consider some not-so-obvious sources, like bread, store-bought sauces, dressings, snack foods, granola bars, and processed meats.

It probably won’t be easy, Zumpano warns. “Sugar is by far the greatest dietary concern when it comes to overall health,” she said. “There is no nutritional value or benefit to sugar, and it is highly addictive, which is what makes it so difficult to reduce.”

While cutting back on sugar, Chiu said it’s important to ensure the rest of your diet is filled with plenty of fiber, healthy fats, and other nutrients.

“In our study, the net effect of healthy and less healthy eating habits is what ultimately influences epigenetic age,” she said.