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THE LEGACY OF RETHA NEWBOLDA Medline search comes up with 59 studies over the past 10 years for which Retha Newbold was principle author or co-author. Newbold primarily looked at the effects of the synthetic estrogen DES on the development and growth of rats; but she also examined other sources of endocrine disruption, including the phytoestrogens genistein and diadzen in soy. Some important published studies by Newbold include: 2000: Exposure to genistein in young rats causes "subtle alterations" in some sexually dimorphic behaviors, including play behavior (Toxicol Sci 2000 Jun;55(2):311-9). 2001: Genistein fed to pregnant rats crosses the placenta and reaches fetal brain tissue (Reprod Toxicol 2001 Mar-Apr;15(2):105-10). 2001: Exposure to genistein during development resulted in decreased prostate weight and several abnormalities in the sexual organs of both males and females. Most interestingly, exposure to genistein resulted in increased renal tubal mineralization (Reprod Toxicol 2001 Nov-Dec;15(6):647-63). 2002: Exposure to genistein resulted in decreased numbers of spleen cells in rats, indicating an adverse effect on the immune system (Toxicol Appl Pharmacol 2002 Jun 15;181(3):219-27). 2002: Neonatal exposure to genistein caused disruption of ovulation cycles in rats (Biol Reprod 2002 Oct;67(4):1285-96). 2002: Neonatal exposure to genistein resulted in abnormal estrous cycles, altered ovarian function, early reproductive senescence and subfertility/infertility in female rats (Biol Reprod 2005 Oct;73(4):798-806). 2006: A limited transfer of genistein to mother's milk occurred when lactating rats were fed dietary genistein (Reprod Toxicol 2006 Apr;21(3):307-12).
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The good news is that reports on the truth about soy are not going away. On May 27, the Los Angeles Times published an article entitled "Is Soy a Fab Bean or Health Danger?" with a subhead, "The benefits of soy, once lauded, are now coming under attack," by Hilary E. MacGregor. MacGregor describes a "soy backlash" and a "fall from grace" in the form of "a crop of books and articles" warning about the dangers, not benefits, of the bean. She even writes that soy has its own "tell-all" book, The Whole Soy Story.
MacGregor notes that even mainstream scientists are pulling back on once-heady health predictions for the bean, quoting Mark Messina as saying, "It's just food! . . . We are talking about diet here. Not the fountain of youth."
Messina, who has organized six symposia devoted to reporting on research on the use of soy in the prevention and treatment of disease, is now kept busy spinning negative findings into more neutral findings. For example, his recent article in the March, 2006 issue of Thyroid minimizes adverse effects on the thyroid by saying that "collectively, the findings provide little evidence that in euthyroid, iodine-replete individuals, soy foods or isoflavones adversely affect thyroid function.' He conceded that "some evidence suggests that soy foods, by inhibiting absorption, may increase the dose of thyroid hormone required by hypothyroid patients," but concludes that "hypothyroid adults need not avoid soy foods" so long as they "make sure their intake of iodine is adequate."
MacGregor describes recent studies that have detracted from the "bean's starry promise," including a January 2006 review of 22 studies which showed that soy protein with isoflavones did not, in fact, "improve" cholesterol levels. This led the American Heart Association to publish an advisory which stated that the AHA "could not recommend the use of isoflavone supplements in pills or food for the prevention of heart disease."
Another review, this one a meta-analysis of 18 "carefully selected" studies, published in the April issue of the Journal of the National Cancer Institute, found that eating soy might slightly reduce the risk of breast cancer, "but not enough to recommend soy foods or supplements." For breast cancer survivors, taking soy supplements could actually be ill-advised, according to coauthor Robert Clarke, a professor at Georgetown University's Lombardi Comprehensive Cancer Center.
The article also mentions possible thyroid and reproductive problems, noting the objections of Dr. Ruth Etzel to the CERHR panel's whitewash.
As the old arguments for eating soy--for example, to ward off cancer and heart disease--crumble, the industry has come up with new ones aimed not at hippies and baby boomers, but at children and the unborn. Anna Wu, a professor of preventive medicine at the University of Southern California, found that Asian girls who eat more soyfoods during adolescence when their breasts are developing seem to get less breast cancer later on. Thought her study did not adequately explore other dietary and lifestyle factors, this idea got an airing in no less than the Wall Street Journal, in a May 30 article, "Can Preteens Take Steps to Reduce the Risk of Breast Cancer."
MacGregor also mentions a "recent study" which suggests "that if women consume soy during the third trimester of pregnancy, it could help program fetuses with a craving for health foods and a good metabolism." No such study comes up in a Medline or Google search and MacGregor did not reply to an email asking her for further information.
The industry is also making hay with a study published in the April, 2006 issue of the Journal of the American Dietetic Association in which almost a quarter of elementary school children chose soymilk over cow's milk at the end of a 14-week trial. "Soymilk has major health advantages over cow's milk," states Jennifer Reilly, RD, the study's lead author. "It avoids the problem of lactose intolerance and skips the bad fats kids seem to like." Currently most US schools do not offer soymilk but the industry is hoping to change that by pushing to make soymilk reimbursable in the federal school lunch program.
Finally, in what has to be the year's most cynical marketing ploy, Soylutions, a Canadian company specializing in the manufacturing and marketing of "health" beverages, has announced a partnership with the Children's Wish Foundation. Until March 2007, Soylutions will donate a portion of the sales from every case of its Earth Shake soy and oats beverages to the foundation. Unfortunately, soy consumed by pregnant women, or by developing children, may prevent their most basic wishes from coming true--normal growth and development and a normal sex life as adults.
Kaayla
T. Daniel, PhD, CCN, earned her Ph.D. in Nutritional Sciences and Anti-Aging
Therapies from the Union Institute and University in Cincinnati and is board-certified
as a clinical nutritionist (CCN) by the International and American Association
of Clinical Nutritionists in Dallas. She is the author of The Whole Soy
Story: The Dark Side of America's Favorite Health Food published in March
2005 by New Trends Publishing. She designs diet, supplement and lifestyle plans
for private clients and is a dynamic speaker and seminar leader who challenges
and entertains her audiences with leading-edge information on clinically proven
ways to prevent and reverse disease and attain optimum health and maximum longevity.
For more information, answers to frequently asked questions or to contact Dr.
Daniel, visit her two websites www.wholesoystory.com
and www.soyfreesolutions.com.
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