Soy, Cow's Milk May Fight Breast Cancer
Nutrients Could Be a Recipe For Breast Cancer Prevention
Sept. 27, 2002 -- Could the latest dietary approach to breast cancer prevention be a tofu shake? A combination of soy and cow's milk could have some beneficial, anti-cancer nutrients.
Such a dietary combination is at the leading edge of what Anna A. Barker, PhD, says is the next generation of "benign medical foods that you take over a lifetime to reduce the risk of cancer." Barker, who is expected to take over as deputy director of the National Cancer Institute, served as a member of the planning committee for the Department of Defense Breast Cancer Research Program meeting in Orlando.
Margot M. Ip, PhD, professor at Roswell Park Cancer Institute, in Buffalo, New York says that Barker's reference to medical foods is apt because she envisions a time when enhanced milk will be the mainstay of cancer prevention. She explains that conjugated linoleic acid, or CLA, is the key to the cow's role in cancer prevention. CLA is a minor fatty acid found in milk and milk products and beef.
When she tested CLA in genetically engineered mice with tumors that mimic human breast cancer "the CLA changed the cells in the cancer and thus cut off their blood supply." Cutting off the blood supply of tumors is a cancer therapy -- called anti-angiogenesis -- that has many researchers intrigued. But most of the news about this cancer-fighting approach has been not been good.
"That's what is so appealing about CLA -- it is completely natural," says Ip.
Moreover, Ip says that dairy chemists are already working on ways to produce super-CLA milk products. "It's a wonderful approach because you can increase CLA potency simply by changing the cow's diet. The cow then becomes a factory to produce a chemopreventive agent," says Ip.
She envisions a time when grocery stores will feature "CLA-fortified milk, cheese, and ice cream." Barker says she also thinks it is feasible, but probably not for another decade or so.
Meanwhile, Coral A. Lamartiniere, PhD, of the department of pharmacology and toxicology, University of Alabama at Birmingham, says breast cancer prevention should start early -- around age 13. "If girls ages 13 to 15 eat one to two servings of tofu a day or consume 40 mg of soy protein, they will reduce their risk of breast cancer as adults," says Lamartiniere.
He says he thinks the most potent cancer-fighting component of soy is a compound called genistein. He noted that studies in Asia found a benefit for genistein at puberty. He demonstrated that by feeding rats a diet containing genistein before exposing them to a cancer-causing drug. The number of breast tumors was reduced by 50%.
Lamartiniere says he has no hesitation recommending soy for teens although he says more studies are needed. Barker says it is too soon to make broad recommendations about the need for soy in girls' diets until science proves a benefit. Meanwhile, she says that a healthy diet and exercise are still the best recommendations to promote overall good health in teens.