Frequently Asked Questions
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Following are questions that have been asked by visitors to the UW Health website and answered by registered dietitians from the UW Carbone Cancer Center. Click on the question for the answer.
Q: My family has a history of estrogen receptor-positive (ER+) breast cancer. Could eating soy or taking soy supplements reduce my risk of breast cancer?
A: Previously there was concern that soy foods may increase risk of estrogen receptor-positive (ER+) breast cancer due to their weak estrogen-like effect. Study regarding soy foods is ongoing and current evidence shows that soy food, in addition to a healthy, plant-based diet, may help protect against breast cancer.
Moderate consumption (1-2 servings per day) of whole soy foods is considered safe. One serving of soy provides about 7 grams of protein and 25 milligrams of isoflavones. Soy foods are a good source of low-fat protein and are rich in dietary fiber, potassium, magnesium, polyunsaturated fat, selenium, and may be fortified with calcium.
Whole soy foods include tofu, soy milk, soy nuts, or edamame. A serving size may include: ½ cup edamame, 1/3 cup tofu, 1 cup of soy milk, ½ cup cooked soy beans, 1/3 cup or 1 ounces soy nuts. Avoid high dose isoflavone supplements and high dose isolated soy protein as the health effects are unknown at this time.
Sources: American Institute for Cancer Research; Academy of Nutrition and Dietetics Oncology Nutrition Dietetic Practice Group
Q: Is tumor growth slowed by eating an alkaline (high pH) diet?
A: This theory is false. Blood pH level is not linked to cancer risk. Furthermore, the foods we eat are incapable of causing significant changes in blood pH. The body naturally maintains acid-base balance regardless of diet; therefore creating a less-acidic, less-cancer-friendly environment is virtually impossible. It can be life threatening if the blood becomes too acidic or alkaline.
Instead, focus on making healthy dietary choices such as eating a wide variety of vegetables, fruits, whole grains; limiting consumption of red and processed meats, and limiting alcohol intake.
Q: Does sugar feed cancer cells?
A: The belief that dietary sugar "feeds" cancer is very common, but the truth is more complex.
Glucose is the form of sugar the body uses to fuel all cells in the body, including cancer cells. We cannot live without sugar (glucose) in our blood. Glucose naturally comes from foods like fruits, vegetables, whole grains, and low-fat dairy products which are rich in phytochemicals, antioxidants as well as vitamins and minerals.
Sugar (glucose) does not make cancer cells grow faster and if cells are starved of sugar it does not slow cancer growth. The connection between sugar and cancer is indirect. While avoiding sugar completely will not slow cancer growth, eating a diet very high in sugar can, over time, increase your risk for cancer.
Eating a lot of high-sugar foods may mean more calories in your diet than you need, which can lead to excess weight and body fat. It is excess body fat that has been significantly linked to greater risk of several types of cancers. In addition, diets high in sugar are oftentimes low in cancer protective nutrients like fiber, antioxidants and phytochemicals. Plant-based foods like whole grains, fruits, vegetables, nuts, seeds, beans are the richest sources of fiber, antioxidants and phytochemicals.