African American women tend to have a greater risk for non-estrogen dependent breast cancer. They tend to get breast cancer at a younger age than other women, and they tend to have higher mortality rates irregardless of the type of cancer.
In 1995, a longitudinal study was launched by the US National Cancer Institute following over 50,000 African American women, looking at breast cancer rates and the subjects diets.
What was found when the study ended in 2007, was that a prudent diet rich in fruits, veggies fish and whole grains was associated with lower breast cancer rates in thin, and in pre-menopausal women.
The "prudent" diets were also low in red and processed meat, carbohydrates and sugars. Overweight women who ate a prudent diet did not show a lower rate, only slim women appeared to be protected by this diet.
There certainly needs to be more studies on risk factors and African American women.