What you eat can play a big role in preventing colorectal cancer, with research showing that fiber-filled foods lower risk; red and processed meats increase it. Now a study hones in on how diet can affect risk, showing that swapping a high-fiber healthy diet for a low-fiber western-style diet alters gut bacteria and signs of inflammation that may play a role in colon cancer.
The study is published in Nature Communications and it adds to a growing body of research on how our bacteria – our microbiota – play a role in cancer risk.
For the study, researchers flipped the diets of 20 African Americans and 20 South Africans for two weeks. All the participants had colonoscopy exams before and after the diet swap.
The Americans were served African-style foods, almost quadrupling their fiber intake to an amount equal to over 3.5 cups of beans. At the same time, they cut their calories from fat in half. Africans went the opposite direction, dramatically cutting their fiber and upping their fat intake.
After two weeks on the African diet, the Americans had less markers of inflammation in the colon while those same markers increased among the Africans eating the less healthy diet. There were also opposing increases and decreases of the compound butyrate, which forms from digesting fiber and is linked to lowering colon cancer risk. The American group was producing more butyrate; the Africans on the American diet less. Continue reading
How soy plays a role in breast cancer risk and recurrence is one of the most common questions we get asked. A large body of human research suggests eating tofu, soy milk and other soy foods in moderation safe. Now an animal study that may help explain what is seen in human research, shows that eating soy foods when young boosts the immune response against tumors, reducing cancer recurrence.
The study is being presented at the American Association for Cancer Research (AACR) annual meeting, and is not yet published.
Soy contains compounds called isoflavones that mimic the effect of estrogen. This raised concerns that it would stimulate breast tumors fueled by estrogen and may interfere with anti-estrogen treatment, such as tamoxifen. Early animal studies did find a link between isoflavones increasing risk of breast cancer. According to the news release, one reason may be that this early animal research used animals that do not have certain immune cells called cytotoxic T cells. These are among the cells that act against breast tumors. Continue reading
Having plenty of tomatoes, carrots and other foods high in carotenoids may reduce the risk of breast cancer, especially the most deadly types, suggests a new study that spanned 20 years. The study, published in The American Journal of Clinical Nutrition, adds to a growing body of research on carotenoids, diet and breast cancer risk.
Carotenoids are a large group of phytochemicals that you can spot in many red, orange and yellow fruits and vegetables. Beta-carotene and lycopene, found in carrots and tomatoes to name a few foods, are a couple of the more well-known carotenoids. They’re also in dark green vegetables, such as kale and spinach.
Previous studies on carotenoids and breast cancer have been mixed. This study builds on research by the same group suggesting that carotenoids affect different types of breast tumors. We wrote about that here.
As in their previous study, the researchers used blood levels of carotenoids to measure intake. Back in 1989-90, they collected blood samples from almost 33,000 women who were part of the Nurses Health Study. Ten years later they collected another sample, with slightly less than half of the women participating again. All the women were regularly answering questionnaires about their health, weight, diet and other factors. Continue reading