Does Sugar Feed Cancer?

March is National Nutrition Month! To honor National Nutrition Month, our resourceful dietician friends have created a number of blogs that will post during the month of March. These blogs will cover popular nutrition topics and myths. Check back often to see what new topics are being blogged about!

“My friend told me to stop eating sugar because I am feeding my cancer. How can I do this? There is sugar in everything I eat. Do I have to give up fruits too?” MYTH

 If you were to perform a quick search about this topic, you will find myths such as “Sugar is toxic” or “Is sugar poison?”  These statements are simply not true and are taken out of context. Most foods consumed in moderation are not harmful to the body.  Many foods contain natural sugar including whole-grain products such as breads, pasta, and rice, and also beans, dairy, fruits, and vegetables. These natural sugars, consumed as part of a healthy diet, provide fiber and nutrients to the body that may decrease your risk for cancer. This all-or-nothing approach to nutrition can restrict many of these cancer-fighting whole foods.

The relationship between sugar and cancer cell growth is very complex. All cells in the body use sugar as fuel, including cancer cells. Cancer cells cannot be starved and they will eat anything they can to grow. Deprive them of starchy foods and they will use proteins and fats to reproduce. Stop eating and they will break down body stores of fat and muscle to survive which may lead to loss of muscle mass and poor immunity.  There is limited evidence linking sugar directly to cancer growth, but foods that are high in calories and fat can lead to weight gain. Obesity has been linked to increased cancer risk (1,2).

Can excess added sugar lead to cancer risk?

Unlike fruits and whole grains that contain natural sugar, refined or processed foods contain added sugars. Sugar may be added to foods in the form of table sugar, honey, agave, rice, or barley syrup to name a few. Although adding sugar to your coffee or tea in moderation is not harmful, too much added sugar may lead to weight gain or may spike insulin levels in the blood that may lead to increased cancer risk. Sources of added sugar or refined carbohydrates that may contribute to obesity include sweetened beverages, desserts, cakes, cookies, or doughnuts.

According to the American Institute for Cancer Research, if you consume excess sugary foods this may lead to greater cancer risk but not in a direct route. Research currently points to excess body fat or insulin production as possible links to cancer growth.  More information is needed to understand how obesity and insulin signaling pathways may lead to cancer cell growth (3).

What can I do to limit my added sugar consumption?

Start by following a plant based diet, rich in whole grains, vegetables and fruits as two thirds of your plate. Fill the other third of your plate with protein containing foods such as beans, legumes, nuts, seeds, lean cuts of chicken and fish. Round out your meals or snacks with calcium rich foods such as low fat dairy, or plant based sources of calcium such as  broccoli , kale, nuts or seeds.  Drink water with each and every meal. Limit your intake of sweetened beverages including fruit juices. Instead choose whole pieces of fruit two to three times per day.  Reserve cakes, cookies and other dessert items for special occasions.

Look for hidden sources of sugar in sauces, gravies, dressings, and other packaged foods. Inspect the ingredient list on the food label. Try to avoid foods that list hidden sources of sugar such as cane, corn, and rice or barley syrup. Sugar can also be listed by its chemical names such as fructose or glucose.   Check the Nutrition Fact Label for added sugar or total sugars.

To limit added sugar in the diet, aim for no more than 6 teaspoons (24 grams) of added sugar for women and 9 teaspoons (36 gram) per day for men. 

For more information on this topic and what to eat during cancer treatment, refer to nutrition webinars on oncolink.org or the American Institute for Cancer Research.

References:

1. Pelicano, H., et al.  Glycoloysis inhibition for anticancer treatment Oncogene 2006;4633-4636
2. Kaaks, R. and Lukanova, A. Energy balance and cancer: The role of insulin and insulin-like growth factor-1.  Proc Nutr Society 2001;60:910106.
3. American Institute of Cancer Research https://www.aicr.org/news/the-sugar-cancer-connection/

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Doris Piccinin, MS, RD, CDE, LDN is a Licensed Registered Dietitian at Penn Medicine’s Department of Patient and Family Services where she works with oncology patients receiving treatment for breast, prostate, bladder, renal and lung cancers. She is also a member of the palliative care team as part of the Radiation Oncology Department. In addition to specializing in oncology, Doris has been a certified diabetes educator for the past 15 years and has worked with adults and children in managing their diabetes through their cancer treatment and beyond. Doris leads the breast and prostate cancer classes at Penn Medicine’s Patient and Family service center and has been the State Regulatory Affairs Specialist from 2013-2016 for the Pennsylvania Academy of Nutrition and Dietetics advocating for nutrition services across the continuum. Services. Her other areas of expertise include cultural nutrition education, survivorship and complementary nutrition practices. She is currently the editor of Mind Body nutrition and wellness for the Dietitians in Integrative and Functional Medicine.