New studies are shining a light on how breast cancer risk can be better assessed. Researchers have found a link between low levels of vitamin D and getting breast cancer at a young age. In particular, women at risk for breast cancer before menopause were found to have low levels of the vitamin in the three months immediately prior to diagnosis. It is believed that this corresponds to the period when the tumor is beginning to settle in, and vitamin D blocks this process. Vitamin D is generally gotten from sunlight, though it is also found in supplements and in some foods.
Although approximately one in eight women will develop breast cancer, it’s far more likely in women over 55; premenopausal breast cancer is comparatively rare. However, obesity and radiation exposure both increase the odds at any age. Women who have a first child after age 35 are also at increased risk. Also raising your odds are a personal or family history. If you had breast cancer, you’re more likely to get it again; if a family member has had it, you’re more likely to get it. This is because of genetic mutations that make someone prone to the disease. People at risk for breast cancer are advised to get plenty of exercise and maintain a healthy weight, to limit alcohol consumption, and to get tested frequently. In some cases women at particularly high risk can get preventative medical or even surgical treatments.
Vitamin D may also be helpful in preventing breast cancer, at least in younger women with high risk. Doctors estimate that if all women made sure to get optimal levels of vitamin D, there would be 58,000 fewer cases of breast cancer every year in the United States. The optimal level, however, is nearly twice the minimum amount considered normal, though far less than what is deemed excessive. Sunlight and supplements are the best sources for vitamin D, though it’s generally added to milk as well. In particular, moderate sun exposure—taking care not to burn—allows your body to produce enough vitamin D with no risk of overproduction, and keeps your breast cancer risk down. Have your doctor test your vitamin D levels, and make sure you’re getting enough.