A study showed that people with good selenium levels had a lower risk of lung, colon, and prostate cancers. A review of many studies found that drinking green tea may help lower the risk of cancers like breast and stomach cancer. Eating fruits, vegetables, and whole grains, being active, and not smoking are still the most important ways to lower cancer risk. In short, vitamin D, omega-3s, selenium, green tea extract, and curcumin may help lower cancer risk. If you care about cancer, please read studies that a low-carb diet could increase overall cancer risk, and vitamin D supplements could strongly reduce cancer death.