Does Beef Fed Soybeans Have More Estrogen

Apr 2014 Upshot

The Superlative 5 Soy Myths
By Judith C. Thalheimer, RD, LDN
Today'southward Dietitian
Vol. sixteen No. iv P. 52

Soyfoods are the subject of several popular misconceptions. Today's Dietitian looks at the latest enquiry to bring the facts to light.

Soy: It'due south a high-quality source of protein, containing all of the essential amino acids; it'southward packed with vitamins and minerals; it has fiber (both soluble and insoluble), omega-3 and omega-six fatty acids, no cholesterol, and very little saturated fatty compared with meat.1 It's been touted for reducing the risk of coronary heart illness, osteoporosis, and some forms of cancer, and there's clinical evidence to back upwardly these assertions.two But in that location'due south also research (and media speculation) saying that soy tin exist detrimental to our health.

What accounts for the conflict, what are the facts, and what communication should nutrition professionals give to clients? Hither's the latest data on five common concerns about soy:

1. All soy products are made from genetically modified organisms (GMOs). Genetic engineering science is used to introduce new characteristics to crops. Some varieties of soybeans have been modified to be herbicide tolerant, assuasive farmers to employ large doses of herbicides to kill weeds without dissentious crops. USDA data point that 93% of all soybeans grown in the United States in 2013 were genetically engineered.iii According to the Soyfoods Clan of North America, "Many soyfoods manufacturers use soybeans and/or ingredients from soybeans that accept not been genetically engineered or that are certified organic, which by USDA organic regulations exclude genetic technology methods. These soyfoods make a statement on the characterization, such as 'organic' or 'made from non-GMO soybeans.'" The quango states that these GMO-free products include soymilk, tofu, tempeh, edamame, and some meat alternatives and nutrition bars.

2. Eating soy increases breast cancer risk. Soybeans and soy products are the richest source of isoflavones in the human being diet. Isoflavones are phytoestrogens, or plant chemicals capable of exerting estrogenlike effects.

Most of the concerns surrounding soyfoods have to practice with their touch on on the many bodily systems influenced by estrogen. Breast cancer, especially estrogen receptor–positive breast cancer, is a primary concern.

According to Marji McCullough, ScD, RD, strategic manager of nutritional epidemiology for the American Cancer Club, epidemiologic studies that followed large populations of good for you women for many years either have shown no association between soy and breast cancer or a protective association from eating soy. Even breast cancer survivors may non need to worry. Three studies looking at women's eating habits and other lifestyle factors after breast cancer establish that, in the combined full of 9,000 breast cancer survivors studied, eating soy actually lowered the risk of breast cancer recurrence, even in women with estrogen receptor–positive tumors (although less and so), and regardless of whether they were taking tamoxifen.four

"I want to brand sure women, including those with a history of breast cancer, know it'southward OK to swallow these foods," McCullough says. "All the same, to find out for sure whether we should specifically recommend soyfoods to chest cancer survivors, researchers would need to replicate these findings, ideally through a controlled study. At the very to the lowest degree, the bear witness from the studies in women reassures us that moderate consumption of soyfoods is probable to be rubber." However, data on the prophylactic of soy supplements is inconclusive, and they shouldn't exist recommended at this fourth dimension.4

McCullough offers an caption why soy's phytoestrogens may non be the powerful cancer causers they were in one case thought to exist. "While isoflavones may act like estrogen, they also have antiestrogen backdrop," she explains. "That is, they tin block the more potent natural estrogens from binding to the estrogen receptor. In addition, they stop the formation of estrogens in fat tissue and stimulate production of a poly peptide that binds estrogen in the blood, making information technology less able to bind to the receptor. They also accept antioxidant and anti-inflammatory properties and may work in other ways to reduce cancer growth."

3. Soy causes feminization in men. High doses of phytoestrogens accept been shown to impair male rats' ability to produce offspring, but the same consequence hasn't been found in male person humans.5 Since many of the concerns related to soy come up from studies in rats and mice, information technology's of import to recognize that rodents metabolize soy isoflavones differently than humans, essentially making these studies inapplicable.2

While individual cases of sex hormone changes in men eating soyfoods accept been reported, these men were consuming extremely high doses of soy (iii quarts of soymilk per twenty-four hours, in one example), and the effects were reversed when the soy intake was discontinued.6 A 2010 review in Fertility and Sterility concluded that "neither isoflavone supplements nor isoflavone-rich soy impact full or free testosterone levels" and that in that location'south "essentially no evidence from 9 identified clinical studies that isoflavone exposure affects circulating estrogen levels in men."vii

4. Soy phytoestrogens inhibit thyroid function. Antisoy websites claim that soy phytoestrogens are "potent anti-thyroid agents that crusade hypothyroidism."8 Indeed, in the May 2011 issue of Clinical Thyroidology , a randomized, double-blind crossover study by Sathyapalan and colleagues plant that six of 60 women with subclinical hypothyroidism converted to clinical hypothyroidism afterwards viii weeks of supplementation with soy protein containing xvi mg of phytoestrogen per day. To mimic a typical Western diet, the study authors also gave women daily soy poly peptide supplements with 2 mg of phytoestrogen. The women in this lower-dose group showed no alter in thyroid function.ix

In his commentary on the published study, Jorge Mestman, MD, reviewed other research in the area and concluded that "but very high doses of soy phytoestrogen supplementation may induce clinical hypothyroidism in a minority of patients with subclinical hypothyroidism."9

For those individuals already existence treated for hypothyroidism, it's important to note that soy consumption decreases assimilation of replacement thyroid hormone, then clients should exist reminded to have such medications on an empty tum as directed. Interestingly, in the same study by Sathyapalan, the high-dose soy phytoestrogens significantly reduced insulin resistance, blood pressure, and inflammation markers.ix

5. Soy-based infant formula tin disrupt growth and reproductive development. Soy-based infant formulas contain significant amounts of soy isoflavones.ten "Infants absorb and metabolize these phytoestrogens," says Victoria J. Drake, PhD, of the Linus Pauling Institute at Oregon State University, "then business organisation has been raised that the estrogenlike effects of soy isoflavones could potentially impact the child's growth and development or adversely influence reproductive and immune function."

To date, this hasn't been constitute to be the case. A 2012 study in Pediatrics compared breast-fed infants to those fed soy- and cow's milk–based formula. Although chest-fed babies scored college on tests of cognitive development, all of the formula-fed babies showed normal growth and development in the start year of life.11

Moreover, a retrospective written report of 811 men and women anile 20 to 34 found no difference in height, weight, fourth dimension of puberty, general health, or pregnancy outcomes between those fed soy-based formula equally infants and those fed moo-cow's milk–based formula.x

"If you lot await at the latest enquiry," Drake says, "there is no disarming evidence that salubrious infants fed soy-based formula are at greater chance for adverse furnishings than those fed cow's milk-based formula."

Moving Forward
Our understanding of the effects of soy isoflavones on the human torso is evolving with ongoing enquiry. The majority of current studies bespeak that the typical corporeality of soy consumed in the Western diet is prophylactic, and even benign, for most people. Excessive consumption of soy, or soy supplementation, however, isn't recommended. Since myths and misconceptions virtually soy are common, it's essential for dietitians to keep upwards with emerging research and data from reliable sources to adequately advise clients and answer their questions.

— Judith C. Thalheimer, RD, LDN, is a freelance diet writer and community educator living outside Philadelphia.

Sources of Soy Isoflavones12
Soybeans are past far the most concentrated source of isoflavones in the human diet.

• The highest concentrations of isoflavones are constitute in soyfoods that aren't highly processed, such as tofu, soymilk, soynuts, tempeh, miso, and edamame. Soy flour and textured soy protein also contain pregnant amounts of isoflavones.

• Soy poly peptide concentrates vary dramatically in their isoflavone content depending on how the protein was extracted.

• Processed soyfoods that contain considerable amounts of non-soy ingredients, such as soy hot dogs, ice foam, or snack confined, have much lower amounts of isoflavones than whole soyfoods.

• Soy oil and soy sauce contain no isoflavones.

— JCT

References
1. Wilson H. A vegan doctor addresses soy myths and misinformation. Complimentary From Damage website. http://freefromharm.org/health-nutrition/vegan-doctor-addresses-soy-myths-and-misinformation/ - sthash.HC9A9xF1.dpuf. Updated January 14, 2014. Accessed January 22, 2014.

2. Soy myths & facts. United Soybean Lath website. http://www.soyconnection.com/sites/default/files/pictures/soy-myths-facts.pdf. Accessed January 22, 2014.

3. Genetically engineered varieties of corn, upland cotton, and soybeans by state and for the United States, 2000-13. US Department of Agriculture Economic Enquiry Service website. http://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us.aspx - .Uvofu_3bQds. Updated July viii, 2013. Accessed January 23, 2014.

four. McCullough M. The lesser line on soy and breast cancer risk. The American Cancer Society website. http://www.cancer.org/cancer/news/expertvoices/post/2012/08/02/the-bottom-line-on-soy-and-breast-cancer-take chances.aspx. August two, 2012.

5. Glover A, Assinder SJ. Acute exposure of adult male rats to dietary phytoestrogens reduces fecundity and alters epididymal steroid hormone receptor expression. J Endocrinol . 2006;189(3):565-573.

vi. Martinez J, Lewi JE. An unusual case of gynecomastia associated with soy production consumption. Endocr Pract . 2008;14(iv):415-418.

seven. Messina Yard. Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence. Fertil Steril . 2010;93(vii):2095-2104.

8. Soy alert! Weston A. Price Foundation website. http://www.westonaprice.org/soy-warning/soy-alert-brochure. Updated March 9, 2009. Accessed February three, 2014.

ix. Sathyapalan T, Manuchehri AM, Thatcher NJ, et al. The effect of soy phytoestrogen supplementation on thyroid status and cardiovascular risk markers in patients with subclinical hypothyroidism: a randomized, double-blind, crossover study. J Clin Endocrinol Metab . 2011;96(five):1442-1449.

ten. Higdon J, Drake VJ. Soy isoflavones. Oregon State University Linus Pauling Institute website. http://lpi.oregonstate.edu/infocenter/phytochemicals/soyiso/. Updated December 2009. Accessed Jan 24, 2014.

xi. Andres A, Cleves MA, Bellando JB, Pivik RT, Casey PH, Badger TM. Developmental status of 1-year-quondam infants fed breast milk, cow's milk formula, or soy formula. Pediatrics . 2012;129(half-dozen):1134-1140.

12. Soy isoflavones. Iowa State University Soybean Extension and Research Programme website. http://extension.agron.iastate.edu/soybean/uses_isoflavones.htm. Updated July 2007. Accessed February 9, 2014.

mossfouldlairity.blogspot.com

Source: https://www.todaysdietitian.com/newarchives/040114p52.shtml