Did you know that what and how much you eat can affect your risk of developing certain cancers? According to theAmerican Cancer Society, about one-third of all cancer-related deaths in the United States are linked to diet and weight, along with inactivity.
Much of the research linking diet and cancer is, “substantial, yet inconclusive,” according to the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR). That’s because it is very difficult to establish a definitive link between cancer and specific foods or nutrients. Most findings come from tracking dietary patterns in different populations.
The WCRF and AICR issued cancer prevention recommendations as part of areport, first published in 2007. Their findings were based on an international panel of scientists’ review of studies related to the connection between food, nutrition, and physical activity and cancer risk. The following are some key dietary recommendations, based on that report and other cancer research.
Eat fruits, vegetables, and whole grains. Plants contain powerful micronutrients, such as flavonoids and carotenoids. Studies show many of these micronutrients are strong antioxidants. They counter damaging reactions (oxidation) from biological processes that can harm or kill cells. Plant nutrients also reduce inflammation, which is associated with the development of cancer, and some can stop or even kill cancer cells.
Like healthy cells, tumor cells need nutrients, which are delivered through a network of tiny blood vessels. Tumors can actually initiate the growth of new blood vessels through a process called angiogenesis. Some compounds in plant foods prevent angiogenesis.
“An anti-angiogenic diet is one comprised of foods and beverages containing naturally occurring substances shown to prevent harmful blood vessels that feed cancers,” says William Li, MD, president and medical director of the Angiogenesis Foundation. “Such a diet includes a wide range of fruits and vegetables, spices, beverages – including fruit juices, teas, coffees, and wine – and proteins that contain naturally occurring cancer-starving activity [certain fish, shellfish, or dairy products, for example].”
In addition to garlic, berries, tomatoes, cruciferous vegetables (such as broccoli and cauliflower), and leafy greens, there are some lesser-known but equally powerful cancer-prevention foods you may want to include in your diet: red onions, apples, papaya, pomegranate, cinnamon, pure pumpkin, and broccoli sprouts (immature broccoli plants). Many of the important chemicals in plants are concentrated in the skins, so eat the whole fruit or vegetable when possible.
Get plenty of fiber. Whole grains, beans, peas, lentils, fruits, and vegetables provide fiber, which helps move food quickly through the digestive tract and helps eliminate carcinogens and estrogen, high levels of which are associated with increased breast cancer risk.
Eat real soy products. Soy intake has been inversely associated with cancer risk, according to a 2012 Journal of Oncology analysis of diet and cancer. Amanda Bontempo, MS, RD, CDN, an ambulatory oncology dietitian at the Perlmutter Cancer Center at NYU Langone Medical Center in New York City, says real soy food, such as tofu and edamame, can be beneficial; but watch out for highly processed soy products (tofurky or soy supplements, for example).
“The timing of exposure to soy is important as well, says Bontempo. “The most protective effects begin before puberty and continue through adulthood.”
Limit meat, alcohol, and dairy. Studies suggest a link between dairy products and prostate cancer risk, while alcohol is associated with an increased risk of liver cancer, breast cancer, and cancers of the digestive tract. Red meat and processed meats, which are high in saturated fats, are associated with increased risk for certain cancers; and Bontempo points out that the link between red and processed meats and colon cancer is well established.
“We also tend to overeat these foods, which leads to chronic, prolonged inflammation, a common denominator in many diseases, including cancer,” Bontempo says. “Less is more. Treat meat as a treat.”
Dr. Li says anti-angiogenic substances can occur in dairy and certain meats, however. “For example, menaquinone (vitamin K2) is anti-angiogenic, and it is a byproduct of bacteria in certain hard cheeses. It also accumulates in the dark meat [thighs]of chickens.”
It’s not just what you eat – it’s how much. Obesity is a significant risk factor for several types of cancer. According to the National Cancer Institute, it has been associated with a higher risk for breast, colon and rectum, endometrial, esophageal, and pancreatic cancers, among others.
“Decrease portion sizes,” Li advises. “Eat only about one-third of what your appetite tells you to eat. If you eat slowly, you’ll fill up. Caloric restriction starves cancer and increases lifespan.”