Should people with cancer avoid sugar? Sugar has a bad rap, but it naturally occurs in whole foods and our cells need it to function. Artificial sugars offer similar sweetness with fewer calories. Whichever type of sugar you reach for, if you have cancer, be sure to consume it in moderation.
Natural Sugars vs. Artificial Sweeteners
The world of sweeteners and sugars can be confusing. The American Heart Association defines naturally occurring sugars as sugars that are, by nature, found in certain foods. This includes fructose in fruit and lactose in milk. And then there is added sugar — what is added to food during processing, like white sugar or brown sugar, high-fructose corn syrup and malt sugar, to name a few. These sugars can be derived from food and injected into processed foods for added sweetness.
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Artificial sweeteners, or sugar substitutes, were created to offer sweetness in a low- or zero-calorie form. According to the Mayo Clinic, you might find sugar substitutes in foods marketed as "sugar-free" or "diet." These sweeteners are made in a laboratory and are not derived from food.
There are some benefits of artificial sweeteners, according to the Mayo Clinic. Unlike table sugar, they don't cause tooth decay or cavities. They may help with weight control due to their low calories, and they generally don't raise blood sugar, making them a good alternative for people living with diabetes.
Some common artificial or high-intensity sweeteners you might notice on food labels, according to the U.S. Food & Drug Administration, include:
But though there are some benefits in these low-calorie options, many critics of artificial sweeteners remain vocal due to the belief that they cause health problems, including cancer.
Sugar Doesn't Feed Cancer
All the cells in our body rely on glucose, or blood sugar, for energy — including cancer cells, according to the Academy of Nutrition and Dietetics. But eating more sugar won't make cancer cells grow faster, per the Mayo Clinic, and avoiding sugar won't slow their growth either.
The same goes for artificial sugar and feeding cancer. "There is no human data that artificial sweeteners feed cancer cells," says Anton Bilchik, MD, PhD, a surgical oncologist at Providence Saint John's Health Center and a professor of surgery and chief of medicine at the Saint John's Cancer Institute in Santa Monica, California.
So where did the concern come from? According to the National Cancer Institute, concerns about the risk of cancer from artificial sugar first arose following early studies showing an association between the artificial sweetener saccharin and bladder cancer in rats.
But as researchers looked more closely at artificial sweeteners, they found this risk didn't translate to humans. An April 2019 research review in Regulatory Toxicology and Pharmacology looked at several studies concerning low- and no-calorie sweeteners and beverages and cancer and found consuming them, and the artificial sweeteners they contain, was not associated with an increased risk of cancer in humans.
Eat Sugar in Moderation
The fact is, your body can't fight cancer without sugar. "Your body has cells that help fight or prevent cancer that depend on sugar to survive," Dr. Bilchik says. He recommends you get natural sugar in moderation.
And don't try to cut out sugar completely, according to the Academy of Nutrition and Dietetics, because maintaining weight can be a challenge during cancer treatments, and the stress of avoiding sugar can actually produce hormones that raise blood sugar levels and decrease immune function.
If there is a link between sugar and cancer growth, it centers around insulin resistance specifically, according to the Academy of Nutrition and Dietetics. So reach for whole food sources of carbohydrates, which are broken down into the sugars that then increase your blood sugar levels. Along with natural sugars, whole food sources of carbohydrates include nutrients your body needs to fight cancer, such as fiber, vitamins, minerals and phytonutrients.
When it comes to artificial sweeteners, even though they don't spike insulin and aren't linked with cancer, the University of Texas MD Anderson Cancer Center recommends limiting them as they don't offer any nutritional benefit.
- American Heart Association: “Sugar 101”
- Mayo Clinic: “Artificial Sweeteners and Other Sugar Substitutes”
- U.S. Food & Drug Administration: “Additional Information About High-Intensity Sweeteners Permitted for Use in Food in the United States”
- Academy of Nutrition and Dietetics: Oncology Nutrition: “Eat Right to Fight Cancer”
- Mayo Clinic: “Cancer Causes: Popular Myths About the Causes of Cancer”
- Anton Bilchik, MD, PhD, MBA, FACS, surgical oncologist, Providence Saint John’s Health Center, Santa Monica, California
- National Cancer Institute: “Artificial Sweeteners and Cancer”
- Regulatory Toxicology and Pharmacology: “Evaluation of Aspartame Cancer Epidemiology Studies Based on Quality Appraisal Criteria”
- University of Texas MD Anderson Cancer Center: “Sugar and Cancer Treatment: 4 Things Patients Should Know”
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