Does Sugar Actually Feed Cancer?

Stacy Shawhan, an oncology dieteticist for eight years, has heard from many cancer patients how their diets affect their prognosis. One question is more common than others: will sugary food and drinks make my cancer worse?

Ms. Shawhan is a cancer specialist at the University of Cincinnati Cancer Center. She said that some patients are afraid to eat. They think that if they stop eating sugar then they can starve their cancer.

The story of'sugar feeding cancer' dates back to the 1920s when a German physiologist observed that some tumors consumed more glucose than normal cells. Low-sugar dieting was soon promoted as a way to cure cancer. Recent surveys from the United States of America and Europe indicate that about a third cancer patients actively avoids sugar.

Experts say that a diet high in sugar may increase cancer risk over the course of a lifetime. However, cutting all sugar out doesn't fight tumors already present.

'Each cell needs glucose. Our brain also requires glucose', said Philipp Scherer a researcher on diabetes at the UT Southwestern Medical Center, Dallas.

A balanced and healthy diet is the best option if you are dealing with cancer or trying to reduce your chances of contracting it.

Sugar and cancer risk

Dr. Scherer stated that sugar is not a cancer-causing substance. No evidence exists that sugar can cause cancer (like smoking cigarettes). Dr. Scherer said that many cancers use fat for their primary source of energy, which means the idea that they prefer glucose to be true is not accurate.

A growing number of studies have linked cancer to the excessive consumption of sugars added (found in cakes, cookies and soft drinks). A large review of 2018 studies cited a number that linked sugary beverages and added sugar to an increased cancer risk.

Shawhan stated that excessive sugar consumption can cause chronic inflammation, which damages cells and may lead to cancer. Sugar consumption can also lower immunity and allow cancer to spread more easily. Consuming excess sugar may alter the metabolism, which can lead to obesity or diabetes. These conditions are known to increase cancer risk.

Sugar and cancer patients

According to Ms. Shawhan, if you are diagnosed with cancer the elimination of sugar does not seem to stop or slow down cancer growth. Ms. Shawhan said that at this stage, the cancer is what is driving growth and not sugar consumption.

Sugar is also essential to most living organisms, according to Dr. Scherer. When sugar is found in natural foods such as dairy products, fruits, and vegetables, then it can be part of a healthy eating plan, according to Natalie Ledesma. She's an oncology dietist at the UCSF Helen Diller Family Comprehensive Cancer Center.

Most experts agree that sugars found in whole foods are not harmful. Ms. Ledesma points out that excessive added sugar consumption has been linked to worse outcomes, including higher mortality rates, in patients with solid tumors such as breast cancer. She said that other cancers could also be affected, but research has been limited on rarer types of cancer.

Santosh Rao is an integrative oncologist with University Hospitals Connor Whole Health, Cleveland. As a result, up to half of cancer patients experience muscle loss. Sometimes, the things doctors prescribe to patients as part of their grueling treatment -- such as Ensure, electrolyte beverages or potatoes -- contain high levels of sugars.

Cancer patients who have certain metabolic disorders should be particularly vigilant, as these diseases can impact their prognosis.

Dr. Rao, for instance, stated that patients with poorly controlled diabetes are more likely to develop breast cancer. A meta-analysis showed that obese patients are more likely to develop colon, breast or uterine cancers.

Eat more healthfully and still enjoy your food

A healthy diet with plenty of fruits and vegetables is the best way to reduce your cancer risk and eat when you've been diagnosed with cancer. Some studies have shown that Mediterranean diets help to reduce cancer risk. Combining carbohydrates with fiber, protein and fat (a dab on an apple slice for example) can prevent spikes in blood glucose levels that, over time could cause havoc to our metabolism and increase the risk of cancer.

Shawhan stated that it is generally OK to consume a small amount of added sugar on a regular basis as long as the rest your diet contains essential nutrients. She suggests sticking to the U.S. Department of Agriculture recommendation of 12 teaspoons of sugar added per day, or even better, following the World Health Organization guidance of 6 teaspoons.

The research on sugar substitutes, their impact on cancer and the risk of cancer is not conclusive. They suggest that we avoid them until more is known. Ms. Ledesma uses naturally sweet ingredients like applesauce and bananas to sweeten up her recipes.

"Cinnamon and ginger are sweet without adding calories or sugar," said Ms. Ledesma.