Can "nutritional insurance" in the form of taking multivitamin supplements actually increase the risk of breast cancer? Swedish investigators followed more than 35,000 older women (49-083 at the beginning) for an average of 10 years, and discovered that after adjusting for known risk factors, the multivitamin users were 19% more likely to develop breast cancer. While this observational study cannot determine cause-and-effect, the authors indicate it is certainly biologically plausible.

PositiveTip: If you eat a healthy and varied diet there is really no need to take multivitamins.

Research often focuses on how specific foods or nutrients affect our risk of disease risk. In reality, our food and nutrients interact in very complex and subtle ways. So it is a good idea to find studies that look at disease risks based on food patterns.

Breast cancer is one of the most common cancers in developed countries. While we know that  factors such as obesity, family history, menstrual history, and the number of children modify women's risk of cancer, these are difficult -- if not impossible -- to change. But diet can be changed!

In a recent study of nearly 120,000 postmenopausal women, the influence of exercise on the development of breast cancer was examined. These women were in the prospective NIH-AARP Diet and Health Study. During nearly seven years of follow-up, 4287 cases of breast cancer were diagnosed.

The researchers looked at exercise done at various times during life, ages 15-18, 19-29, 35-39 and “recently” (past 10 years) in relationship to the development of breast cancer. The results showed that exercise in the remote past didn’t protect women from developing breast cancer later in life.

Today the media often reports on the purported benefits of moderate alcohol use in preventing cardiovascular disease. However, the dark side of that apparently good news is that even moderate alcohol use by women significantly increases their risk of breast cancer. The American Institute for Cancer Research believes there is ample and consistent evidence that alcoholic drinks are a cause of both premenopausal and postmenopausal breast cancer. (Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective,  p. 165-168: 2007)

PositiveTip: Abstain even from moderate amounts of alcohol to lower the risk of breast cancer.

Phytoestrogens found in soy foods are thought to reduce the risk of breast cancer in women. However, there has been some concern that the estrogen-like effects of soy isoflavones might not be good for breast cancer patients. In a study of over 5000 female breast cancer survivors in China, those who consumed the most tofu, soy milk, and fresh soy beans had a 29% lower mortality rate and 32% less recurrence compared to those who ate the least soy foods. This was seen in both estrogen receptor positive and negative tumors, as well as early and late stage cancer.

PositiveTip: Soy foods are safe for patients with breast cancer and may offer some protection from recurrence.

One of the most feared complications of breast cancer surgery is lymphedema, a potentially disfiguring, disabling, and incurable problem. Consequently, weight lifting has generally been proscribed for those women with this condition--preventing them from getting the well-established health benefits of strength-training, including increased bone density. Now, in a year-long, randomized, controlled trial of twice weekly progressive weight lifting in 141 women with lymphedema there was no significant effect on limb swelling. In fact, those weight lifting had reduced symptoms, increased strength, and fewer exacerbations than the controls.

A number of observational studies suggest that breast-feeding reduces pre-menopausal breast cancer risk, but large prospective studies have been lacking until now. Using a cohort of the Nurses' Health Study II, investigators report that women who had a first-degree relative with breast cancer and ever breast-fed had a lower risk of pre-menopausal breast cancer compared to those who had never breast-fed. This benefit did not seem to persist for women without a family history of breast-cancer.

PositiveTip: Women, especially with a family history of breast cancer, should be encouraged to breast-feed their infants. It's good for the baby and good for Mom!

Ladies, here is more evidence that physical activity may prevent breast cancer. A prospective study conducted at the Cooper Clinic in Dallas, Texas examined 14,811 women aged 20 to 83 years old with no history of breast cancer. At the beginning of the study each subject received a maximal exercise test to determine their cardiorespiratory fitness. The results of these tests placed them in low, moderate, or high fitness categories. They were followed for an average of 16 years.

Women in the low fitness group were 2.4 times more likely to develop breast cancer when compared to those in the high fitness group!