Debunking the Myth: Does Sugar Feed Cancer Cells?
In recent years, there has been a growing concern among cancer patients about the impact of sugar consumption on their condition. Many have adopted the belief that eliminating sugar from their diets can starve cancer cells and improve their prognosis. However, experts are now debunking this popular misconception.
Stacy Shawhan, an oncology dietitian at the University of Cincinnati Cancer Center, has witnessed firsthand the fear and confusion surrounding sugar and its alleged role in cancer growth. “Cancer patients are so vulnerable, and some of them are terrified to eat,” she said. “They think, ‘If I stop eating sugar, then I can starve my cancer.'”
The idea that sugar feeds cancer can be traced back to the 1920s when a German physiologist noticed that tumor cells consumed more glucose than healthy cells. This observation led to the emergence of low-sugar diets claiming to cure cancer. Today, polls from both the United States and Europe reveal that approximately one-third of cancer patients actively avoid sugar.
While it is true that diets high in added sugars may increase the risk of cancer over a lifetime, cutting out all sugars does not actually combat existing tumors. “Every cell requires glucose, our brain requires glucose,” explained Philipp Scherer, a diabetes researcher at UT Southwestern Medical Center in Dallas. In other words, a balanced, healthy diet is the best approach for cancer patients and those looking to reduce their risk of developing cancer.
Contrary to popular belief, sugar itself is not a carcinogen. There is no evidence to suggest that consuming sugar directly causes cancer in the same way that smoking cigarettes does. Moreover, “many, many cancers prefer to use fat as their primary energy source, so even the idea that cancers prefer glucose isn’t quite true,” stated Dr. Scherer.
However, a limited yet growing body of evidence has linked the overconsumption of added sugars, such as those found in cookies, cakes, and soft drinks, to an increased risk of cancer. Excess sugar consumption can spark chronic inflammation in some individuals, damaging cells and potentially leading to cancer. Additionally, consuming too much sugar can lower immunity, making it easier for cancer cells to spread. Furthermore, the metabolic alterations caused by excessive sugar intake can contribute to obesity and diabetes, both of which increase the likelihood of developing cancer.
Once a person is diagnosed with cancer, eliminating sugar from their diet does not significantly impact the growth of tumors in most cases. “By this point, it is not sugar intake that is driving cancer growth, but the cancer itself,” explained Shawhan. Sugar is essential for most living organisms and, when consumed through natural sources like dairy products, fruits, and vegetables, it forms part of a healthy diet, according to Natalie Ledesma, an oncology dietitian at the UCSF Helen Diller Family Comprehensive Cancer Center.
While it may not be necessary to completely abstain from sugar found naturally in whole foods, the consumption of excessive added sugars has been associated with worse outcomes and higher mortality rates in patients with specific solid tumors such as breast, colon, and prostate cancers. However, research on rarer cancer types and their relationship with sugar intake remains limited.
Maintaining a balanced and healthy diet is crucial for cancer patients, but it is equally important not to become afraid of food. Some treatments recommended by doctors, such as electrolyte drinks, can contain high levels of sugar, making it challenging to manage sugar intake. Cancer patients with certain metabolic diseases should be particularly vigilant, as these conditions can affect their prognosis. Poorly controlled diabetes, for instance, increases the aggressiveness of breast cancer, as shown in studies.
To eat healthfully and reduce cancer risk, experts recommend following a diet rich in whole fruits and vegetables. Mediterranean diets, known to lower cancer risk, meet these criteria. Pairing carbohydrates with protein, fiber, and healthy fats helps regulate glucose levels and curb the potential detrimental effects of excessive sugar consumption.
In general, indulging in a small amount of added sugar, even on a daily basis, is acceptable as long as the rest of the diet provides essential nutrients. The U.S. Department of Agriculture suggests limiting added sugar intake to twelve teaspoons a day, while the World Health Organization recommends a maximum of six teaspoons.
The influence of sugar substitutes on cancer and cancer risk remains inconclusive, and experts advise avoiding them until more research is conducted. Instead, sweetening recipes with naturally sweet foods like bananas, frozen berries, and applesauce can provide the desired sweetness without the added calories or sugar. “Cinnamon or ginger offer a sweetness with no added calories or sugar,” suggested Ledesma.
As cancer patients navigate their diets, it is crucial to strike a balance that ensures proper nutrition while not succumbing to fear or deprivation. By following expert guidance and maintaining a well-rounded diet, cancer patients can manage their condition effectively and improve their overall well-being.
Connie Chang is a freelance science and parenting writer based in Silicon Valley.