August 12, 2019

The Connection Between Sugar-Sweetened Beverages and Cancer

It’s tempting to sip something sweet during warm summer days, whether it’s fresh-squeezed orange juice at the breakfast table or a frosty glass of lemonade on the patio. But indulging in too many sugar-rich beverages could possibly increase your risk of developing cancer, new research suggests.

A recent study published in The British Medical Journal found that people who had a modest increase of sugar-sweetened beverages, including 100 percent fruit juices, were 18 percent more likely to develop cancer overall and 22 percent more likely to develop breast cancer. An increase of just 100 milliliters — a little more than one-half cup — was associated with increased cancer risk.

“I think it’s significant,” says Vincent Cryns, MD, a UW Health physician and researcher whose lab studies the connections between metabolism and cancer. “We have a lot of data on sugar-sweetened beverages being related to increased obesity, type II diabetes and poor health outcomes, but we didn’t have clear data on the association between sugar-sweetened beverages and cancer before now. It’s another reason for reducing consumption of these kinds of drinks.”

The study involved more than 101,000 participants in France who self-reported their dietary habits. Such studies have their limitations: they tend to attract more health-conscious volunteers, and people often under-report their consumption levels. While the study didn’t find an increase in cancer risk associated with artificially sweetened “diet” beverages, fewer people in the study reported consuming those beverages, and more research is needed, he notes.

Cryns wasn’t surprised by the study’s findings. “Biologically, there are plausible reasons why consumption of sugary beverages could drive cancer risk,” he says. “It can lead to increased fat tissue and obesity, and that itself can drive cancer. We know that obesity fuels cancer in a number of ways. Fat cells themselves can make molecules that drive tumor growth.”

But obesity isn’t the only factor, and the study in France found an increase in cancer risk even when controlling for weight.

“These beverages have a high-glycemic index. They tend to increase blood insulin levels, and insulin can also be a growth factor for tumors,” Cryns explains. “They can also cause inflammation and oxidative stress, byproducts of metabolism that can damage cellular molecules like DNA and proteins. Certainly part of the effects of sugary beverages are being driven by obesity, but it may not be the whole story.”

Tips to Tame the Sugar Cravings

So what’s a cancer-conscious sweets lover to do? Cryns offers these tips:

Sugar form matters. Added sugars in food aren’t terrific for your health either, but sugary drinks, which are quickly absorbed into the bloodstream, have a harsher effect on the body. “Sugars can be derived from complex carbohydrates, like when your body breaks down bread, but that release is more gradual,” he explains. The occasional sweetened beverage is probably OK, but research hasn’t yet determined how much sugar is safe.

Choose healthier drink options. “Instead of a soft drink, drink water or sparkling water that doesn’t contain any sugar,” suggests Cryns, who avoids all soda himself. And watch out for hidden sources of sugar, such as sports drinks.

Satisfy your sweet tooth with whole fruit. “Even though this study didn’t look at whole fruits, there is data from other studies that suggests that sugars in whole fruits don’t carry the same adverse effects that 100 percent fruit juices do,” he says.

Look at other parts of your diet. You can also lower your risk of cancer by adopting a plant-based diet, avoiding large amounts of saturated fat and trans fat, and restricting your consumption of processed foods, he notes. The American Cancer Society offers many healthy eating tips.

Watch your weight. “Many people don’t understand that obesity is linked to increased cancer risk,” he says. “Being overweight is the No. 1 preventable cause of cancer. It has surpassed smoking, and it’s a factor we can do something about.”

Be especially mindful if you have a history of cancer. “The good news for cancer survivors is that there are a lot of things that you can do to stay healthy and reduce your risk of cancer reoccurrence,” he says. “Physical activity is an important part of the equation. There are many studies trying to understand the health benefits of physical exercise in terms of cancer risk reduction, and certainly a substantial part of that is avoiding weight gain and obesity.”

Get some expert advice. Be proactive and talk to your health care provider to get a personalized diet plan. “Health care providers, including physicians, nurses, and dietitians, can really help personalize lifestyle choices that incorporate healthy eating and physical activity,” he says. “That’s a tremendously underutilized resource.”

UW Health Services

UW Carbone Cancer Center

Endocinrology, Diabetes and Metabolism

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