Women who eat more eggs as teenagers may be less likely to develop breast cancer later on, say researchers this week.
The research, published in Breast Cancer Research, found that higher levels of egg consumption during adolescence are associated with a decreased risk of breast cancer. Eating dietary fibre and vegetable fat was also attributed to a reduced risk of developing the disease while butter appeared to increase the risk.
Scientists have for some time been studying the links between diet and breast cancer. They have found some immigrant populations in the United States to have lower rates of breast cancer than the general population, and believe this to be due to a diet different to the typical American diet. Within a generation, the risk of developing breast cancer in these immigrant populations has normally risen to that of the general population suggesting that exposure to certain foods during childhood and adolescence may be critical in establishing a woman's risk of developing breast cancer.
Lindsay Frazier and colleagues from Harvard Medical School and the Harvard School of Public Health asked 121,707 women about their eating habits during high school years. They compiled data on daily servings of foods such as milk, fruit, vegetables, meats, and sweets, which account for major sources of fat, vitamins and other essential nutrients. The analysis was controlled to take into account other factors that may affect the risk of developing breast cancer, such as family history, diagnosis of benign breast disease, and use of hormone replacement therapy.
The results of the survey revealed that eating more eggs, vegetable fat and dietary fibre between the ages of 12-18 may decrease the risk for breast cancer, while high consumption of butter appeared to increase the risk. The researchers suggest that eggs may protect because of their high levels of essential amino acids, vitamins and minerals, and dietary fibre may have a similar effect through its ability to bind oestrogen within the digestive system. Oestrogen, a sex hormone, is essential for the normal growth and development of the breast and, yet, has also been associated with increasing a woman's risk for breast cancer.
It is less clear why butter appears to have such a radically different effect from vegetable oils. However higher consumption of fat in the diet is generally thought to raise the risk of breast cancer. The authors believe that more information on the composition of vegetable oils will be needed before an explanation can be given. They stress that their work represents a preliminary study and that future studies are needed to establish a clearer picture of the links between diet and breast cancer.