There is a popular thought that sugar can feed and even cause cancer. But is this true?

By Janice Baker, RD, CDE, CNSC, BC ADM

“Does sugar feed cancer?” is one of the most frequent questions that come to dietitians who work in the oncology setting, as well as with other health concerns such as diabetes.  While researchers continue to investigate the relationship between sugar intake and cancer, it remains a source of uncertainty and fear for many cancer patients and their caregivers. Let’s take a look at some information about the connection between sugar and cancer and steps you can take to support your overall health.

Sugar comes in many different forms, but the simplest form is a single molecule called glucose. All cells, including cancer cells, use glucose as their primary fuel. Glucose comes from any food that contains carbohydrates including healthful foods like vegetables, fruits, whole grains, and dairy. Glucose also comes from refined carbohydrates and added sugars like white bread, pasta, sweets and sweetened beverages.

The idea that sugar, or glucose, could fuel the growth of cancer cells may lead some people to unnecessarily avoid all carbohydrate-containing foods. This approach assumes that if cancer cells need glucose, then cutting it out of one’s diet will stop cancer from growing.

Unfortunately, it’s not that simple. All of our healthy cells need glucose to function, and there is no way for our bodies to let healthy cells have the glucose they need, but not give it to the cancer cells. Without adequate carbohydrate intake from foods we eat, our bodies will make glucose from other sources, including protein and fat.

Glucose is that critical for our cells to survive and function properly. Not consuming sufficient carbohydrates can lead to the breakdown of protein stores in our body, which can contribute to muscle loss and possibly malnutrition. Following a restricted diet with very low amounts of carbohydrates can also cause unintentional weight loss. This can impact the ability to tolerate cancer treatment. Restricting carbohydrates also eliminates foods that are good sources of fiber, vitamins, minerals and immune supporting phytonutrients.

To date, there are no randomized controlled trials showing sugar causes cancer. There is, however, an indirect link between sugar and cancer. Eating a lot of high sugar foods such as cakes, cookies, and sweetened beverages can contribute to an excess caloric intake. This may lead to weight gain and excess body fat. Research has shown that excessive abdominal fat may increase the risk of certain cancers including colorectal, postmenopausal breast, ovarian, and pancreatic cancer.[1]

While it is not necessary to completely avoid sugar, reducing added sugars and consuming nutrient-dense, high fiber carbohydrates may be most effective.

Nutrition tips to support whole body health:

  1. CHOOSE WHOLE GRAINS like whole wheat bread, pasta, brown rice, or quinoa. The fiber and extra nutrition keeps your digestive tract strong and healthy and provides important vitamins and fuel for the healthy bacteria in the GI tract.
  2. LIMIT ADDED SUGARS. There is room for “fun foods”, however portion size should be considered in the context of a healthful diet.  A registered dietitian can assist you in working out a meal plan to include foods you really enjoy while meeting your health goals.
  3. CONSUME A DIET RICH IN VEGETABLES & FRUIT which contain water, fiber, vitamins, minerals and immune supporting phytonutrients. Choose whole fruit, frozen fruit, or canned fruit packed in its own juice. Dried fruit is good for traveling and 100% juice can work well, especially if you have problems chewing, swallowing or if you need extra calories to maintain your weight.
  4. INCLUDE A LEAN PROTEIN SOURCE with each meal and snack like poultry, fish, eggs, dairy, tofu, beans, nuts or seeds.
  5. BALANCE YOUR PLATE. Have a good portion of your plate filled with vegetables and fruit. Include protein rich and the rest with whole grains and/or starchy vegetables such as peas, corn or potatoes.
  6. STAY WELL HYDRATED. Drink plenty of water – this is important for digestion, hydration and to reduce the risk of blood clots.
  7. STAY ACTIVE. Regular, consistent activity stimulates metabolism, bone and muscle strength. Light activity throughout the day does make a difference, so break up sitting with activities that you enjoy as well as hobbies, household chores, and pet care.

[1] https://www.nature.com/ articles/onc2017278? foxtrotcallback=true

DAR -0042 RevA 06/2019