The relationship between soy products and breast cancer seems to be ever evolving. A new study sheds some light on the subject, but by no means closes the conversation. An ongoing Chinese study followed just over 5,000 breast cancer survivors between the ages of 20 and 75. The participants were broken up into two groups: those that ate more than 15 grams of soy protein daily and those that ate under five grams of soy protein daily. Four years into the study, the survival rate was higher and the recurrence rate was lower in the women who ate more soy.
In the past, it was theorized that soy isoflavones stimulated the estrogen receptors in breast-cancer cells, but this latest study may indicate the opposite is true. The lead author of the study, cancer epidemiologist Dr. Xiao Ou Shu, MD, PhD, theorizes that
"Soy isoflavones may compete with estrogens produced by the body. Soy isoflavones may also reduce the body's production of estrogen, and increase clearance of these hormones from the circulation — all of which together reduce the overall amount of estrogen in the body."
While other breast cancer experts are intrigued with these findings, they would like more evidence to support the potential benefits of soy before recommending their patients add more soy products to their diets. Once again, moderation reigns when it comes to diet. Dr. Larry Norton, medical director of the Evelyn Lauder Breast Center at Memorial Sloan-Kettering Cancer Center in New York City, tells his patients that soy certainly has its place in a well balanced diet, but he doesn't recommend soy as the only source of protein nor does he recommend soy supplements.
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