Adolescence: Key Time to Lower Breast Cancer Risk?

Adolescence: Key Time to Lower Breast Cancer Risk?

Although breast cancer most commonly occurs later in life, research suggests that it develops and progresses over the course of a lifetime. Studies now indicate that lifestyle habits during adolescence may significantly affect risk of breast cancer later in life.

Cancer anywhere in the body begins with damage to the DNA of genes within particular cells. During puberty, increasing estrogen levels cause breast cells to divide rapidly. This leaves them more vulnerable to DNA damage, and affords them less chance to repair the damage before it becomes permanent.

In addition, a woman’s breast cells do not fully mature until she experiences a full-term pregnancy. According to Cornell University’s Program on Breast Cancer and Environmental Risk Factors in New York State, breast cells that are not fully mature bind carcinogens (cancer-causing substances) more strongly and are not as efficient at repairing DNA damage as mature breast cells.

The earlier a girl starts menstruating, the more menstrual cycles she will have, which means more total exposure to estrogen during her childbearing years. Some researchers suggest a 2-year delay in the onset of menstruation could mean a 10% drop in risk. Athletes usually begin menstruating at a slightly older age than inactive girls; reports on the impact of moderate activity vary. Regular exercise might also lower risk by strengthening the immune system.

Although age when menstruation begins is an established risk factor for breast cancer, trying to delay it with dieting, extreme weight loss or stressful exercise is not safe. This can lead to severe bone loss or eating disorders. A healthy active lifestyle allowing normal development should be the goal.

Few studies have examined smoking during adolescence as a risk factor for breast cancer. However, the carcinogens in cigarette smoke do circulate through the body, and could be especially damaging during adolescence when breast cells are rapidly dividing.

Because adolescents experience an increased vulnerability to the kind of DNA damage that can begin the process of breast cancer development, diets high in fruits, vegetables, and whole grains may be particularly valuable. THese foods supply antioxidant vitamins that help protect DNA from damaging substances, along with a variety of nutrients essential for DNA repair. Natural phytochemicals in these foods can also stimulate enzymes that deactivate cancer-causing substances before they can do their damage. The American Institute for Cancer Research (AICR) recommendation for 5 or more servings of various vegetables and fruits each day may turn out to be even more important for adolescents than it is for adults.

Alcohol consumption has been identified as a likely risk factor for breast cancer at all ages, though it is not clear precisely why this is so. It may be that alcohol increases estrogen levels, makes breast cells more susceptible to damage, or contributes to risk in some other, as yet undefined way. We do not know if drinking at an early age is especially risky in this regard, but these unanswered questions provide another good reason to encourage teenagers to avoid alcohol.

A landmark report on diet and cancer risk from AICR notes that a plant-based diet, avoidance of alcohol, regular physical activity and a healthy weight could reduce the incidence of breast cancer by 33 to 55%. The report specifically cautions that these steps will have the most benefit if established before puberty and continued throughout life. More research in this area is needed, but establishing healthy eating habits early in life remains the best way to promote long term health.

Karen Collins, MS, RD

Karen Collins, MS, RD, CDN, holds a BS degree in nutrition from Purdue University and an MS degree in nutrition from Cornell University, where she also was an instructor. She has been involved with the American Institute for Cancer Research for more than 15 years as a writer, nutrition education consultant, and public speaker. Ms. Collins has authored brochures, newsletter articles and cookbooks. For the past eight years, she has written two weekly newspaper columns syndicated to more than 700 newspapers nationwide and carried weekly on the MSNBC website. In addition, Ms. Collins conducts a private practice in nutrition counseling, working with individuals and groups to develop realistic strategies for achieving health goals.