The relationship between soy and breast cancer risk has been studied in a number of ways. A new study as well as other earlier research has looked at the geographic and ethnic differences in risk. Research has shown that Asian women living in Asia have a lower risk of breast cancer. But Asian women living in the United States have breast cancer rates similar to the general U.S. population.
Soy in the diet is one factor that might explain this. Asians eat much more soy and begin eating it at a much younger age than people in the United States.
But the "soy story" and its possible connection to breast cancer is complicated by other factors. Most women living in Asia depend on soy as their main source of protein. They consume only small amounts of beef, chicken, and pork—which means less animal fat and other possibly unhealthy substances (such as growth hormones and antibiotics) in these animal protein sources. Also, compared to the average woman in the United States, the average Asian woman:
- eats more fresh vegetables,
- is closer to her ideal body weight,
- is more physically active, and
- is less likely to consume significant amounts of alcohol.
All of these other factors can add up to a healthier lifestyle from childhood and could explain the lower overall risk of breast cancer in Asian women living in Asia.
Also, this study does suggest that what you eat as a child can affect your preferences for certain foods, which can affect your risk of developing cancer as an adult. Encouraging your children to try and enjoy a variety of foods is worth the effort. Choose the most nutritionally rich foods you can from each food group each day; those packed with vitamins, minerals, fiber, and other nutrients, but also lower in calories. The reward can be good growth and development as your child grows and a reduced risk of heart disease and cancer when he or she is an adult.
Visit our Nutrition section to learn more about healthy eating and soy.