Natural Health News – New evidence suggests that we should not take the protective effects soybeans at face value.
Many women believe that supplementation of soy may help reduce the risk of breast cancer. But a new study suggests caution may be necessary.
Recently, scientists at the Cancer Center Memorial Sloan-Kettering and Weill Cornell Medical College in New York, New York, conducted a randomized placebo-controlled trial of the effects of soy supplements on the expression gene (the way genes work in the body) and biological markers of risk of breast cancer among women diagnosed with invasive breast cancer.
The study, conducted between 2003 and 2007 at the Memorial Sloan-Kettering, included 140 women who had recently undergone breast biopsies and who were diagnosed with stage 1 or 2 breast cancer and programmed to have mastectomy or lumpectomy two to three weeks later.
During the time between diagnosis and surgery (a period of 7-30 days), women were randomized to receive either a supplement of soy protein or a placebo (milk protein ).
tumor tissue samples taken before and after surgery and then analyzed to determine levels of genistein, a component of soy phytoestrogens. Not all women had high levels of genistein, but about 20% made and between scientists found changes in several genes that promote cell cycle progression and cell proliferation -. Changes that can lead to cell growth of breast cancer
Writing in Journal of the National Cancer Institute , the authors conclude that the data raise concerns that soy can have a stimulating effect on breast cancer in some women.
A accompanying editorial discusses how the timing of supplementation of soy is critical and reviews the evidence in the literature on phytoestrogens, which are contained in soy, and action known in breast cancer.
It is suggested that the study: “… illustrates the dangers of consuming phytoestrogens too early, around menopause, but biology of estrogen in estrogen-deprived conditions suggests that phytoestrogens may have a benefit a decade after menopause. ”
further precautions that appropriate doses of soy consumption and timing are critical considerations that require greater understanding.
At the moment it seems reasonable to advise women not over-consume soy to the exclusion of other healthy foods. Variety – and moderation in all things – is still the best dietary advice
- For more information on the risks of high soy consumption, see our article . Soja – how the healthiest food in the world is making us ill