FAQ: Does Sugar Feed Cancer Cells?

A fellow caregiver asked...

Does sugar feed cancer cells?

Expert Answer

Beth Reardon, M.S., R.D., L.D.N., is Caring.com senior food and nutrition editor and the director of integrative nutrition at Duke Integrative Medicine. As a practitioner of integrative nutrition, Reardon takes a holistic approach to wellness, recognizing that the foundation for optimal health and healing begins with a health-promoting diet. As a practitioner of integrative nutrition, Reardon takes a holistic approach to wellness, recognizing that the foundation for optimal health and healing begins with a health-promoting diet.

The short answer is no -- with a big qualifying "but." Glucose (sugar) is the primary fuel for most of the cells in the body, including the brain, muscles, and -- yes -- even cancer cells. It's the preferred fuel because it's easily taken up by most cells throughout the body to use as an energy source.

But to say that sugar feeds cancer is a misstatement. Elevated levels of blood sugar stimulate the release of insulin from the pancreas. If insulin levels remain elevated for long periods of time, this causes an increase in inflammation -- basically, the body's normal immune response goes into a kind of unhealthy overdrive. Then, through a complex and coordinated series of events, tumor cells use this inflammatory process to signal cells to multiply. It's the prolonged release of insulin in response to chronic elevations in blood sugar that's the true problem.

The goal, therefore -- and the most important concept to understand -- is that through the foods you choose to eat, you can create an anti-inflammatory environment in the body. You can stabilize blood sugar and insulin levels.

To accomplish this and avoid those damaging fluctuations in blood sugar:

  • Minimize intakes of processed foods that are high in refined flours and sugars, foods obviously high in white starches (sugar and white flour), and juices.

  • Choose foods that are close to their original forms found in nature (whole fruits instead of fruit juices, whole grains instead of white bread, etc.).

  • Switch to more whole grains and high-fiber foods. Good examples: steel-cut oats, brown rice.

  • Look for colorful produce. Great anti-inflammatory choices include blueberries, red grapes, cruciferous vegetables (broccoli, cauliflower), and tomatoes.

  • Consume naturally healthy fats found in nuts, seeds, nut butters, extra-virgin olive oil, canola oil, and avocadoes. Avoid trans fats (check nutrition labels) and oils such as corn, vegetable, and safflower, as well as mayonnaise and most processed salad dressings (the kind found bottled on grocery store shelves).

  • Limit alcohol consumption to one to two glasses per day; red wine is the best choice, since it has the most anti-inflammatory chemicals.