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A new placebo-controlled, double-blinded research study showed no benefit from soy supplements in reducing osteoporosis or the symptoms of menopause.
SOY (ISOFLAVONES), OSTEOPOROSIS, AND THE SYMPTOMS OF MENOPAUSE
As I discuss in detail in my recent book, A Cancer Prevention Guide for the Human Race, combination hormone replacement therapy (HRT) for the symptoms of menopause have been clearly linked to an increased risk of breast cancer. (This important topic is also the subject of my next book, which will be published in 2012.) Since the preliminary findings of the landmark Women’s Health Initiative study were released in 2002, proving the link between HRT and breast cancer, many women and their physicians have been searching for safer alternatives to HRT in an effort to relieve the symptoms of menopause, and to reduce the risk of thinning of the bones (osteoporosis).
There have been several public health research studies that have suggested a role for soy foods in the prevention of both osteoporosis (“thin bones”) and menopausal symptoms. Indeed, the findings of these studies make scientific sense, as soy isoflavones, which are present in many soy food products (and especially in tofu), act as a weak form of estrogen. (It is the loss of estrogen production in the ovaries, after menopause, that leads to both osteoporosis and the unpleasant symptoms of menopause in postmenopausal women.) However, as with the vast majority of disease prevention research in general, the available research data linking soy isoflavones to improvements in bone density and menopausal symptoms has been in the form of survey-based studies, and other relatively unreliable types of research studies. Now, a newly published prospective, randomized, placebo-controlled, doubled-blinded clinical research study takes a closer (and more accurate) look at the impact of soy isoflavone supplements on osteoporosis and menopausal symptoms. This clinical research study appears in the current issue of the Archives of Internal Medicine.
In this study, 122 postmenopausal women were randomized to receive a daily soy isoflavone supplement pill (200 mg), while 126 postmenopausal women were randomized to receive a placebo (sugar) pill that was identical in appearance to the soy isoflavone pills. Neither the research study volunteers nor the research staff knew which patient volunteers received the soy isoflavone tablets and which volunteers received the placebo pills until the research study was completed. These patient volunteers were all followed for an average of 2 years. Bone density measurements were performed at the beginning of the study, and then again 2 years later. Common menopausal symptoms were also tracked throughout the duration of this study.
After 2 years of observation, there was no significant difference in bone density measurements between the two groups of women who participated in this clinical research study (in both groups of women, there was an average bone density loss of about 2 percent over the 2-year period of this study). Moreover, the women in the soy isoflavone group actually reported ahigher incidence of hot flashes and constipation than the women in the placebo group.
In this well-controlled prospective, randomized, doubled-blinded, placebo-controlled clinical research study, a daily supplement of 200 mg of soy isoflavones neither improved postmenopausal bone density loss nor improved the most troublesome symptoms of menopause. (Whether or not higher doses of soy isoflavones, or natural soy foods instead of soy isoflavone supplements, might have shown some beneficial effect on bone density loss or menopausal symptoms in postmenopausal women cannot be answered by this study.) Therefore, this study convincingly shows that even relatively large daily doses of purified soy isoflavones have no beneficial effect on either bone density loss or menopausal symptoms in postmenopausal women. Based upon the results of this study, if you are currently taking soy isoflavone supplements in an effort to reduce your risk of osteoporosis, or the symptoms of menopause, this high-level clinical research study indicates that you are probably wasting your time and money on such supplements. (However, as I discuss in A Cancer Prevention Guide for the Human Race, soy foods may actually reduce a woman’s lifetime risk of developing breast cancer, particularly if consumed during early adolescence and early adulthood, and soy products may also decrease a man’s lifetime risk of developing prostate cancer.)
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For a groundbreaking overview of cancer risks, and evidence-based strategies to reduce your risk of developing cancer, order your copy of my new book, “A Cancer Prevention Guide for the Human Race,” from Amazon, Barnes & Noble, Books-A-Million,Vroman’s Bookstore, and other fine bookstores!
On Thanksgiving Day, 2010, A Cancer Prevention Guide for the Human Race was ranked #6 among all cancer-related books on the Amazon.com “Top 100 Bestseller’s List” for Kindle e-books! On Christmas Day, 2010, A Cancer Prevention Guide for the Human Race was the #1 book on the Amazon.com “Top 100 New Book Releases in Cancer” list!
Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, professor of surgery, cancer researcher, oncology consultant, and a widely published author
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