October is Breast Cancer Awareness Month and at the forefront of breast cancer prevention is early detection. The earlier the disease is detected, the more likely treatment will succeed. In addition, many lifestyle factors can help prevent the development of breast cancer as well as other cancers.
Question: What are the most effective lifestyle factors that can help to reduce breast cancer risk?
Answer: It should be no surprise that exercise and diet are two key preventive measures. Regular exercise not only helps lower risk, but it even provides benefits during treatment and recovery from breast cancer. For risk reduction, the American Cancer Society recommends 45 to 60 minutes of “intentional physical activity” at least five days per week. Recent research reviews estimate that regular physical activity can decrease the risk of breast cancer by 25 percent to 30 percent.
How diet might help to prevent breast cancer is more difficult to determine. Many researchers have attempted to identify foods and types of diets that play a role in the prevention or cause of breast cancer. To date, many associations have been identified between specific foods and breast cancer risk but these types of studies cannot establish cause-and-effect relationships.
In addition, there is a fair amount of disagreement between researchers related to specific dietary components, such as dietary fat. At this time there is no clear association between the amount or type of dietary fat consumed and the risk of breast cancer.
Q: Are there foods that are beneficial in preventing breast cancer?
A: There is good evidence that vegetables and fruits provide healthful benefits. Fish and beans also show some evidence of being protective. Skimmed milk and fermented milk products are also associated with reduced risk.
Q: Are there foods that should be avoided?
A: Possibly the clearest link is to alcohol. Women who consume two to five drinks daily increase their risk of breast cancer about 1.5 times that of women who drink no alcohol.
Q: Should meat be avoided?
A: Excessive consumption of meat and poultry with skin is associated with increased breast cancer risk, but this risk is primarily associated with how the meats and poultry are prepared.
Grilling at high heat and frying these foods is associated with increased risk, but consumption of boiled meats, such as that consumed in stews and soups, is not.
The beneficial carotenoids found in many vegetables are fat-soluble and are much better absorbed when consumed with another food that provides some fat or oil.
This may explain why meats consumed in stews and tomato sauces are not associated with breast cancer risk whereas risk increases with excessive consumption of grilled or fried meats.
Dietary patterns are likely important but are very difficult to study. At this time, the best rule of thumb is to:
1. Exercise.
2. Maintain a normal body weight.
3. Consume a diet with a variety of foods, including vegetables and fruits.
4. Consume meats primarily in stews and soups with vegetables.
5. Limit alcohol to a drink a day.
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Joannie Dobbs, Ph.D., C.N.S., and Alan Titchenal, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.
