Does Sugar Really Feed Cancer? – 07/15/2023 – Balance and Health

During the eight years that Stacy Shawhan worked as an oncology nutritionist, she heard many questions from her cancer patients about how diet influences their prognosis. But one question came up more than the others: Will consuming sugary foods and drinks feed my cancer cells, making my condition worse?

“Cancer patients are very vulnerable, and some of them are afraid to eat,” said Shawhan, who practices at the University of Cincinnati Cancer Center. “They think, ‘If I stop eating sugar, I can starve my cancer.’

The “sugar feeds cancer” narrative dates back to the 1920s, when a German physiologist noticed that some tumor cells consumed more glucose than healthy cells. Shortly thereafter, low-sugar diets claiming to cure cancer appeared. Recent surveys in the United States and Europe have suggested that about a third of cancer patients actively avoid sugar.

While experts say diets high in added sugars can increase your lifelong risk of cancer, cutting out all sugars doesn’t actually fight existing tumors.

“Every cell requires glucose, our brain requires glucose,” said Philipp Scherer, a diabetes researcher at the University of Texas Southwestern Medical Center in Dallas.

In other words, the best way to eat if you have cancer — or are trying to lower your risk of getting the disease — is to eat a healthy, balanced diet.

Role of sugar in cancer risk

Sugar is not a carcinogen, Scherer said. There is no evidence that eating sugar per se causes cancer (as, say, smoking cigarettes would). Furthermore, Scherer added, “Many cancers prefer to use fat as their main source of energy, so even the idea that cancers prefer glucose is not quite real.”

Still, a limited but growing body of evidence has linked excessive consumption of added sugars (the kind found in cookies, cakes and soft drinks) to cancer. For example, a large review of studies published in 2018 cited several that linked consumption of sugar and sugary drinks to an increased risk of cancer.

Excessive sugar consumption has been shown to cause chronic inflammation in some people, which can damage cells that can become cancerous, Shawhan said. Excessive consumption of added sugars also lowers immunity, which can allow cancer cells to spread more easily. And consuming too much sugar can alter your metabolism in ways that can lead to obesity and diabetes, conditions known to increase your chances of getting cancer.

Sugar and cancer patients

Once a person is diagnosed with cancer, eliminating sugar doesn’t seem to slow or stop tumor growth in most cases, Shawhan said. “At this point, it’s not sugar intake that’s driving cancer growth, but the cancer itself.”

Furthermore, sugar is essential for most living things, Scherer said. And when it occurs naturally in foods like dairy, fruits and vegetables, it’s part of a healthy diet, said Natalie Ledesma, an oncology nutritionist at the Helen Diller Cancer Center at the University of California, San Francisco.

For the most part, experts agree that there’s no need to abstain from the sugars contained in whole foods. But Ledesma notes that excessive consumption of added sugar has been linked to worse outcomes — including higher death rates — in patients with certain solid tumors, such as breast, colon and prostate cancers. Other cancers can also be affected, she said, but research on rarer types is limited.

It’s also important for cancer patients to manage their diets without being afraid of food, said Santosh Rao, an integrative oncologist at Connor Whole Health University Hospitals in Cleveland. Up to half of them experience muscle loss as a result of the disease. And sometimes the things doctors recommend for patients during rounds of grueling treatments — like Ensure, electrolyte drinks or even potatoes — can be high in sugars, Shawhan said.

While all people should avoid diets high in added sugars, cancer patients with certain metabolic diseases must be especially vigilant because these diseases can affect their prognosis.

“Patients with poorly controlled diabetes tend to have more aggressive breast cancer,” for example, said Rao. And a meta-analysis suggested that obese patients were more likely to die from colon, breast and uterine cancer.

How to eat healthily without depriving yourself

The best way to lower your risk of cancer and to eat if you have a cancer diagnosis is to eat a healthy diet with lots of whole fruits and vegetables. Mediterranean diets achieve these goals and help reduce the risk of cancer, according to some studies. Combining carbs with protein, fiber, and fat (a little peanut butter on a slice of apple, for example) prevents spikes in glucose that can, over time, wreak havoc on our metabolism and increase our risk of cancer.

Generally speaking, Shawhan said, it’s okay to have a little added sugar, even daily, as long as you’re getting essential nutrients from the rest of your diet. She recommends sticking to the US Department of Agriculture’s suggestion of 12 teaspoons of added sugar a day — or, better yet, the World Health Organization’s guideline: six teaspoons.

Research on sugar substitutes and their influence on cancer and cancer risk is inconclusive. Experts suggest avoiding them until we learn more. Ledesma prefers instead to sweeten her recipes with naturally sweet foods like bananas, frozen berries and applesauce, which are often included in her non-dairy ice creams.

“Cinnamon or ginger offer sweetness without added calories or sugar,” she said.