Back to July 2005: Buying Healthy Food and Drink
Are dairy products safe?
- Question from Devon: Are dairy products safe?
- Answers —David Grotto, R.D., L.D.: “Safe” is an interesting way of asking. It's somewhat of a mixed bag when it comes to fighting cancer. About dairy products, there was an interested study in The Lancet that showed that premenopausal women who had a small increase in insulin growth factor (IGF1) had up to 7 times the breast cancer risk of women with lower levels. The reason I bring that up is there was a study of dairy benefits showing insulin growth factor can possibly increase breast cancer. The casein in dairy can increase IGF.
There are some wonderful aspects of dairy we applaud—calcium is necessary to fight osteoporosis, so it's about calcium balance. We also know that dairy contains CLA, conjugated linoleic acid, which is a good transfat that may fight breast cancer, and whey protein which may have profound benefits. (By the way, the “runny” part of cottage cheese is whey and the chunky part is the “curds.”) But because of the IGF, we don't promote dairy for people with breast cancer. - Penny Block, M.A.: IGF1 is not a chemical that's added by the dairy industry. It's a component of cow's milk, but it can contribute to the growth of breast cancer cells.