October is Breast Cancer awareness month and although more and more people are becoming aware of the fact that breast cancer is a significant concern for females across the population, many fail to realize the role lifestyle plays in its prevention and management. Breast cancer accounts for over one third of invasive cancers in women. Epidemiological studies have linked diet composition with prognosis, indicating the strong role diet may play in prevention. Many medical professionals are recognizing that a physically active lifestyle, combined with weight management and a calorie controlled, low-fat diet high in vegetables, fruits, fiber and low in red meat intake are important components to reducing the risk. From the literature it seems that physical activity helps mediate inflammatory chemicals associated with obesity, while diet modification has a positive effect on gonadal hormones, retinoid-like activities of carotenoids, and increases the protective effects of biologically active dietary constituents.
Controlling ones weight seems to be a pressing issue to reduce the risk of developing breast cancer and preventing reoccurrence in survivors. Strong evidence supports the link between obesity and breast cancer risk. Due to the fact that breast cancer risk is positively associated with body mass index and energy intake, and inversely associated with physical activity, one of the first steps to prevention is attaining an active lifestyle and practicing calorie control within one’s diet. This seems to be even more important for premenopausal females. In a large cohort study involving 49,613 Canadian women, researchers linked premenopausal obesity and relatively high energy intake with a possible increased risk for breast cancer development. In addition, individuals with positive energy imbalances who did not engage in vigorous physical activity and had a relatively high body mass index, also experienced an elevated risk. Body mass index seems to be an important marker for postmenopausal females in particular, as a strong link between anthropometric measures of adiposity and risk seems to exist.
One of the newer hypotheses attempting to explain the link between obesity and breast cancer to recently gain scientific attention is the concentration of inflammatory markers associated with being overweight. Recent literature has identified adiponectin (a peptide hormone) and related cytokines associated with obesity and insulin resistance, as a plausible connecting link. Although much more research is necessary to identify the actual connection between obesity and breast cancer, researchers suggest that the low serum adiponectin and high serum leptin and resistin concentrations associated with obesity-related low grade inflammation may be independent risk factors for metastasis of cancer. Again postmenopausal females seem to have a distinct risk with adipocytokine (fat cell chemical) disturbances.
In addition to calorie control and physical activity, the nutrients in the diet also play an important role in reducing the risk of breast cancer development. Diet and breast cancer risk has been investigated rather extensively, leading to a collective group of recommendations for prevention. Due to the fact that breast cancer, like most forms of cancer, is a heterogeneous disease, different dietary factors may affect breast cancer subgroups differently. Likewise, premenopausal dietary intakes do not seem to provide the same protection after menopause in all nutrients. For instance, intakes of low-fat dairy products rich in calcium and vitamin D were inversely associated with breast cancer risk in premenopausal females, but were statistically insignificant for postmenopausal women. Dietary fat seems to be similar in its hormonal discretion. In a research investigation of more than 90,000 females between the ages of 26 and 46, the greatest risk for breast cancer was found in the group with the highest fat intake, with animal fat, not vegetable fat, being most associated with the risk. These findings were not consistent for postmenopausal females, where prospective studies have not supported this association. Researchers suggest red meat and high-fat dairy as key dietary agitators, possibly due to the high concentration of saturated fat. Interestingly, though, red meat intake was strongly related to elevated risk of breast cancers that were estrogen and progesterone receptor positive, but not in cases where the diagnosis was hormone receptor negative. This supports the notion that each type of breast cancer has potentially different stimuli.
Alcohol intake has also been implicated in elevated risk for breast cancer. It is suggested that heavy alcohol use is associated with increased risk, but so is moderate consumption. Researchers suggest that individuals who consume alcohol at moderate to high levels should increase their folate intake, which seems to mitigate the risk at some level. The inverse association between folate and breast cancer risk was significant among women consuming at least one drink per day. Researchers also suggest that Vitamins B6 and B12 may provide some benefit as well in premenopausal female, but again not for those who are postmenopausal.
Researchers suggest that a physically active lifestyle and a diet rich in fruits and vegetables and high in fiber is the right approach to prevention. Additionally low-fat dairy products seem to offer added benefit. To the contrary, a diet rich in starch, processed foods, and animal fat seems to increase risk and therefore should be appropriately limited in the diet. Key nutrients associated with possible reduced risk include Vitamins A, C, D, and calcium. Vitamins E and B may provide some benefit for diets low in those nutrients, but high intakes have not shown statistical value in decreasing the risk of breast cancer development. Some doctors recommend that breast cancer patients take antioxidant supplements, whereas others do not fully support the recommendation. This being said, among the prospective epidemiologic studies conducted on diet and breast cancer incidence to date, there is no single association that is completely consistent and statistically significant, with the exception of alcohol intake, overweight, and weight gain.
Categories of Risk
Getting older –Risk significantly increases after age 50. Approximately 77% of women diagnosed with breast cancer each year are over age 50.
Direct family history – Having a first degree relative who has breast cancer.
Genetics - Women with the BRCA1 or BRCA2 gene are at higher risk.
Breast lesions - A previous breast biopsy result of atypical hyperplasia (lobular or ductal) increases a woman's breast cancer risk by 4 to 5 times.
Distant family history - This refers to breast cancer in more distant relatives such as aunts, grandmothers and cousins.
Previous abnormal breast biopsy - Biopsies showing fibroadenomas with complex features, hyperplasia without atypia, sclerosing adenosis and solitary papilloma.
Age at childbirth - First pregnancy after age 30 or never having children.
Early menstruation - Menses before age 12.
Late menopause - Menopause occuring after age 55.
Weight - Being overweight, high level of central adiposity, with excess caloric and fat intake, increases your risk, especially after menopause.
Other cancer in the family - A family history of cancer of the ovaries, cervix, uterus or colon increases your risk.
Heritage - Female descendents of Eastern and Central European Jews (Ashkenazi) are at increased risk.
Alcohol - Consuming 2-5 drinks daily, have about 1.5 times the risk of women who drink no alcohol.
Race - Caucasian women are at a slightly higher risk of developing breast cancer than are African-American, Asian, Hispanic and Native American women.
Hormone Replacement Therapy (HRT) – Long-term use of combined estrogen and progesterone increases the risk of breast cancer. This risk seems to return to that of the general population after discontinuing them for 5 years or more.