Childhood Milk Consumption and Breast Cancer
~ December 2001 No.139 ~
Human babies can survive on either human milk or cow´s milk. What about other types of milk? Humans are the only animal to consume milk after weaning. Milk and milk products are a large part of many people´s diets throughout their lives. Our taste for milk may be unique among the animal kingdom, but there may be good reason to continue drinking milk. New findings out of Norway indicate that the consumption of milk beginning in childhood and continuing into the adult years may provide protection against the occurrence of breast cancer.
Milk is usually included in the diet because it is relatively inexpensive and is a highly digestible source of protein, fat and calcium. Most food charts recommend 2-3 servings /day of milk and milk products - more for growing children and lactating women. Regular cow´s milk contains 3.8% milk fat (m.f.) and provides 65 calories per 100 ml. For those looking for a lower calorie alternative, 2% m.f. , 1% m.f. and skimmed milk which contains only 0.1% m.f. are available.
A group in Norway headed by Dr. Anette Hjartaker has recently reported that drinking milk may provide some protection against breast cancer in women. Dr. Hjartaker and her research group found that in the 6.2 years after collecting data from 48,844 women, 317 cases of breast cancer had been diagnosed. When the diets of the women surveyed were examined with respect to milk consumption during childhood, it was found that women who had consumed more than 3 glasses of milk per day had about 56 % less chance of contracting breast cancer than those women who had consumed no milk during childhood. This statistical trend was found for women 34 to 39 years of age but not for women 40-49 years old. The analyses that took into consideration the type of milk or the amount of milk fat consumed showed no clear effect on protection against breast cancer. When the analyses combined both childhood and adult milk consumption, there was a clear effect on the reduction of breast cancer incidence.
As with most analyses that look for relationships between incidence of disease and dietary intake, there is no obvious explanation of what there may be in milk that could protect against breast cancer. Why there should be a protective effect in younger women and not older women is also not easy to explain. Studies of this sort are a starting point. Follow-up studies are necessary to determine whether milk contains some ingredient that can protect against breast cancer.
Childhood and adult milk consumption and risk of premenopausal breast cancer in a cohort of 48,844 women