Wednesday, June 17, 2009

Hormonal Imbalance, Thyroid Issues, and Asian Soy Intake History


  • (graph linked to study) Environmental Health Perspectives Supplements Volume 110, Number 3, June 2002 // Goitrogenic and Estrogenic Activity of Soy Isoflavones // Dr. Daniel R. Doerge and Dr. Daniel M. Sheehan // Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas.
  • Abstract -- Soy is known to produce estrogenic isoflavones. Here, we briefly review the evidence for binding of isoflavones to the estrogen receptor, in vivo estrogenicity and developmental toxicity, and estrogen developmental carcinogenesis in rats. Genistein, the major soy isoflavone, also has a frank estrogenic effect in women. We then focus on evidence from animal and human studies suggesting a link between soy consumption and goiter, an activity independent of estrogenicity. Iodine deficiency greatly increases soy antithyroid effects, whereas iodine supplementation is protective. Thus, soy effects on the thyroid involve the critical relationship between iodine status and thyroid function. In rats consuming genistein-fortified diets, genistein was measured in the thyroid at levels that produced dose-dependent and significant inactivation of rat and human thyroid peroxidase (TPO) in vitro. Furthermore, rat TPO activity was dose-dependently reduced by up to 80%. Although these effects are clear and reproducible, other measures of thyroid function in vivo (serum levels of triiodothyronine, thyroxine, and thyroid-stimulating hormone ; thyroid weight ; and thyroid histopathology) were all normal. Additional factors appear necessary for soy to cause overt thyroid toxicity. These clearly include iodine deficiency but may also include additional soy components, other defects of hormone synthesis, or additional goitrogenic dietary factors. Although safety testing of natural products, including soy products, is not required, the possibility that widely consumed soy products may cause harm in the human population via either or both estrogenic and goitrogenic activities is of concern. Rigorous, high-quality experimental and human research into soy toxicity is the best way to address these concerns. Similar studies in wildlife populations are also appropriate.


  • The below is taken from Health & Learning Info, A 2 Z of Health, Beuaty, and Fitness -- an online magazine:

    What Does the Thyroid Do? "The thyroid’s main job is to produce thyroid hormone. Hormones are chemicals that are secreted by glands which act like messengers telling specific body parts what to do. Thyroid hormones help the body make energy, keep body temperature regulated and assist other organs in their function. The thyroid produces two major hormones: triiodothyronine and thyroxine, commonly referred to as T3 and T4. (The “3” and the “4” relate directly to the amount of iodine molecules which are used to create these hormones.)" .... "Soy contains goitrogens, plant chemicals that inhibit thyroid function. And 99% percent of the soy we consume is genetically modified, otherwise known as GMO. Soy has one of the highest percentages of contamination by pesticides of any of our foods. Soy is rich in phytic acid, a chemical that blocks the uptake of essential minerals. Soy has the highest phytate levels of all the grains and legumes. The phytates have been found to be resistant even to long slow cooking in an effort to denature them. There exist hundreds of research articles on phytic acid and their effects, including binding with certain nutrients like iron to inhibit their absorption."

    CNN.com: Health, Diet & Fitness


    White, for one, worries that soy may speed the aging of brain cells. He recently found evidence that the brains of elderly people who ate tofu at least twice a week for 30 years were aging faster than normal. Tests designed to assess memory and analytical ability showed that their brains functioned as if they were four years older than their actual age, White says of his study published in the April 2000 issue of the Journal of the American College of Nutrition.


    Another fear is that the estrogen-like substances in soy may dampen the function of the thyroid. Consuming 40 milligrams of isoflavones a day can slow the production of thyroid hormone, says Dr. Larrian Gillespie, author of "The Menopause Diet" and "The Goddess Diet." (One tablespoon of soy powder contains about 25 milligrams of isoflavones, while most isoflavone supplements come in 40-milligram pills.)


    According to Gillespie, within a few weeks of regularly consuming 40 milligrams of isoflavones, some women feel fatigued, constipated and achy all over. Some also gain weight and have heavier menstrual periods. Menopausal women are at particular risk, since they're already prone to hypothyroidism. "Women think it's because of hormones and don't realize they're symptoms of hypothyroidism," Gillespie says. "Once they stop the soy, they say, 'I'm feeling fine again.' " ...


    ....Messina, for instance, recommends a daily serving of soy: perhaps 1 cup of soy milk or 3 to 4 ounces of tofu.


    So, how much soy did Asians eat?


    Not much, even though we, as a society have been led by expert mass marketing to think otherwise. Soy has never, ever been a food staple in Asian history. The exception was that the poor often used the soybean to fill their empty bellies during times of famine. Even then, the soybeans were prepared in such a way as to neutralize the natural and inherent soy toxins thus proving that even ancient Asians understood the soybean better than we do today.


    To consume a serving of tofu and a couple of glasses of soy milk has become commonplace for many Americans. Soy is also touted as the original protein source for those perusing a vegetarian lifestyle.


    This is absolutely in excess of the amount of soy that Asians consume. In native Asia, from where so much of this "research" is purported to have originated, a tablespoon or two of soy is simply used as a condiment. According to K. C. Chang, the editor of Food in Chinese Culture, the total caloric intake of soy in the Chinese diet during the 1930's was only 1.5 percent as compared to 65 percent for pork products.


    The huge concern about consuming large amounts of soy products lies in the mega dosing of isoflavones. If consumers follow the nutritional advice of Protein Technologies International (manufacturers of soy-isolated protein) their daily genistein intake (an isoflavin found in soy) could exceed 200 milligrams per day. It goes without saying this level of genistein intake should be avoided.


    Up until only two decades ago, soy was considered unfit to eat. By Asians, mind you! To see the hold soy products have on the USA marketplace is truly a miracle. Agricultural literature clearly depicts the soybean and its first and foremost use as a crop rotation plant used to fix nitrogen in the soil. Soybeans did not serve as any form of food until the advent of the Chow Dynasty. During this period, fermentation techniques brought us some of the soy edibles we see today, such as tempeh, soy sauce and natto. In the second century B.C., the Chinese discovered a porridge of cooked soybeans could be precipitated with calcium sulphate or magnesium sulphate (Plaster of Paris or Epsom salts) to make tofu. Sound healthy?


    The Chinese did not eat unfermented soybeans as they did other legumes because the soybean contains large amounts of antinutrients (toxins). First among them is hemagglutinin, a clot promoting substance that makes red blood cells clump together. Soy is rich in enzyme inhibitors that block the action of much needed enzymes required to digest proteins. These inhibitors are not deactivated during cooking. They can cause gastric distress and chronic deficiencies in amino acid uptake. Protein inhibitors and hemagglutinin are scientifically proven to inhibit growth, as evidenced in studies of weanling rats that eventually failed to thrive.


    Soy contains goitrogens, plant chemicals that inhibit thyroid function. And 99% percent of the soy we consume is genetically modified, otherwise known as GMO. Soy has one of the highest percentages of contamination by pesticides of any of our foods. Soy is rich in phytic acid, a chemical that blocks the uptake of essential minerals. Soy has the highest phytate levels of all the grains and legumes. The phytates have been found to be resistant even to long slow cooking in an effort to denature them. There exist hundreds of research articles on phytic acid and their effects, including binding with certain nutrients like iron to inhibit their absorption.


    The marketing push for more soy products has been relentless and global. Public relations firms help convert research projects into newspaper articles and advertising copy. It has worked like a charm. Soy protein is now found in a majority of supermarket breads. Soy can be found blended in the regular old corn tortilla. Try to find a salad dressing in a health food store whose first ingredient is not soy oil. Advertising for a new soy enriched loaf from Allied Bakeries in Britain targets menopausal women seeking relief from hot flashes. It goes on and on.


    For more information on the great soy misinformation please consult the well-written and respected book entitled The Whole Soy Story by Dr. Kaayla Daniel.


    About The Author:

    Dr. Linda Posh MS SLP ND brings a fresh perspective to natural health and nutrition. She packs a solid educational background with degrees in organic chemistry, psychology and a Masters in Communication Sciences and Disorders. Visit www.Nutra-Resources.com for information.

    Tuesday, June 16, 2009

    Soy Causes Thyroid Problems (among other things)

    (Imported Article) Soy is not the best thing for people. Not a lot of people know this, but just 5-8 ounces of soy milk is too much soy isoflavons in ones diet (30grams). The USDA site lists the isoflavone content of a total of 128 foods, including foods such as vegetarian hot dogs soybeans, chickpeas and tofu. This can help you in deciding how much soy to include in your diet. So vegetarians, count your "soy intake," rather than your calorie intake. The following link is to my "Drinking Hole" site where this article from Thyroid-info.com comes from, enjoy

    (click picture for another article)


    Do Soy Foods Negatively Affect Your Thyroid? A Look at the Downsides of Soy

    by Mary Shomon


    It seems that there's isn't a newspaper, magazine or news program that hasn't recently featured a story on the amazing health benefits of soy food products and soy/isoflavone supplements. Soy is promoted as a healthy alternative to estrogen replacement for some women, as a possibly way to reduce the risk of breast cancer, as a way to minimize menopause symptoms, and as a healthier, low-fat protein alternative for meats and poultry. But what all the positive stories fail to mention is that there is a very real -- but very overlooked -- downside to the heavy or long-term use of soy products.


    Soy products increase the risk of thyroid disease. And this danger is particularly great for infants on soy formula.


    This is not information that the powerful and profitable U.S. soy industry wants you to know. The sale of soy products is big business, and the increasing demand for soy protein products, soy powders and soy isoflavone supplements is making that an even more profitable business than ever before.


    In researching my book, Living Well With Hypothyroidism, which covers the issue of soy products and the thyroid in great depth, I talked to Dr. Mike Fitzpatrick, an environmental scientist and phytoestrogen researcher who has conducted in-depth studies on soy, particularly the use of soy formulas. Dr. Fitzpatrick makes it clear that soy products can have a detrminental affect on both adults and infants. In particular, he firmly believe that soy formula manufacturers should remove the isoflavones -- that part of the soy products that act as anti-thyroid agents -- from their products.


    Researchers have identified that the isoflavones act as potent anti-thyroid agents, and are capable of suppressing thyroid function, and causing or worsening hypothyroidism. Soy is a phytoestrogen, and therefore acts in the body much like a hormone, so it's no surprise that it interacts with the delicate balance of the thyroid's hormonal systems. High consumption of soy products are also proven to cause goiter, (Anti-thyroid isoflavones from soybean: isolation, characterization, and mechanisms of action, Divi RL; Chang HC; Doerge DR, National Center for Toxicological Research, Jefferson, AR 72079, USA, Biochem Pharmacol, 1997 Nov, 54:10, 1087-96)

    Note: The best source of information on soy and its negative impact on health can be found at the Soy Online Service, and in particular, its page on phytoestrogenic effects of soy, and impact on the thyroid.




    Isoflavones belong to the flavonoid or bioflavonoid family of chemicals, and are considered endocrine disruptors -- plants or other products that act as hormones, disrupting the endocrine system, and in some cases, this disruption involves acting as an anti-thyroid agent. (The grain millet, for example, contains high levels of flavonoids, and is commonly known as problematic for thyroid function). Flavonoids inhibit thyroid peroxidase (TPO), which disturbs proper thyroid function.


    The March 1999 issue of Natural Health magazine has a feature on soy that quotes Daniel R. Doerge, Ph.D., a researcher at the Food and Drug Aministration's National Center for Toxicological Research. Dr. Doerge has researched soy's anti-thyroid properties, and has said "...I see substantial risks from taking soy supplements or eating huge amounts of soyfoods for their putative disease preventive value. There is definitely potential for interaction with the thyroid."


    One UK study of premenopausal women gave 60 grams of soy protein per day for one month. This was found to disrupt the menstrual cycle, with the effects of the isoflavones continuing for a full three months after stopping the soy in the diet. Isoflavones are also known to modify fertility and change sex hormone status. Isoflavones have been shown to have serious health effects -- including infertility, thyroid disease or liver disease -- on a number of mammals.


    Dr. Fitzpatrick believes that people with hypothyroidism should avoid soy products, because, "any inhibition of TPO will clearly work against anyone trying to correct an hypothyroid state." In addition, he believes that the current promotion of soy as a health food will result in an increase in thyroid disorders.


    The Dangers of Soy Formulas

    Since the late 1950's, it has been known that soy formulas contain anti-thyroid agents. Infants on
    soy formula are particularly vulnerable to developing autoimmune thyroid disease when exposed to high exposure of isoflavones over time. ( Breast and soy-formula feedings in early infancy and the prevalence of autoimmune thyroid disease in children. Fort P; Moses N; Fasano M; Goldberg T; Lifshitz F Department of Pediatrics, North Shore University Hospital-Cornell University Medical College, Manhasset, New York 11030. J Am Coll Nutr, 1990 Apr, 9:2, 164-7) This study found that the frequency of feedings with soy-based milk formulas in early life was noticeably higher in children with autoimmune thyroid disease, and thyroid problems were almost triple in those soy formula-fed children compared to their siblings and healthy unrelated children. Dr. Fitzpatrick even believes that long-term feeding with soy formulas inhibits TPO to such an extent that long-term elevated TSH levels can also raise the risk of thyroid cancer.


    Not much is being done in the U.S. to make parents aware of the thyroid-related dangers of soy formulas, or to alert the public that heavy soy consumption may be a danger to thyroid function. Other countries, however, are far ahead of the U.S. In July of 1996, the British Department of Health issued a warning that the phytoestrogens found in soy-based infant formulas could adversely affect infant health. The warning was clear, indicating that soy formula should only be given to babies on the advice of a health professional. They advised that babies who cannot be breastfed or who have allergies to other formulas be given alternatives to soy-based formulas.


    Why more information is not available about these concerns is probably a function of the tremendous strength of the large agricultural companies that dominate America's soy market. One thing is clear, however. At the same time that health experts, and nearly every radio and television health program in the nation touts soy as the miracle health food of the new millenium, the United States pediatric and medical community needs to get more on top of this issue, and begin to counsel their patients regarding the serious impact use of soy products can have on thyroid function.


    How Much Soy is Safe?

    According to the Soy Online Service, for infants, any soy is too much. For adults, just 30 mg of soy isoflavones per day is the amount found to have a negative impact on thyroid function. This amount of soy isoflavones is found in just 5-8 ounces of soy milk, or 1.5 ounces of miso. For more information on how much soy is too much, see the Soy Online Service guidance page.


    The USDA has launched a website that is promoting the health benefits of use of soy and soy foods. The USDA site lists the isoflavone content of a total of 128 foods, including foods such as vegetarian hot dogs soybeans, chickpeas and tofu. This can help you in deciding how much soy to include in your diet.



    More information


    For more information on soy products, see: