|Soy and Osteoporosis: Not a Leg to Stand On|
|Monday, 18 December 2006 21:36|
Soy as the all-natural solution for osteoporosis? The latest ploy of the soy industry is to fan women's fears about bone loss and distract them from recent news that soy does not prevent heart disease, and that it worsens cardiomyopathy, impairs fertility and may increase breast cancer risk.
Consumers who bone up on the issue, however, will find that the research is inconsistent and contradictory at best and that soy truly does not have a leg to stand on. A recent study that the industry has chosen not to promote came out of Yale New Haven Hospital in July and compared calcium bioavailability in women eating soy versus those eating meat. The researchers concluded in the Journal of Nutrition, "These data indicate that when soy protein is substituted for meat protein, there is an acute decline in dietary calcium bioavailability."
This finding explodes a myth widely propagated by vegetarians, namely that meat and eggs cause a loss of calcium, leading the body to strip calcium from storage in the bones, ultimately resulting in osteopenia or osteoporosis.
The study most often cited to justify this claim came out in 1988 in the Journal of Clinical Endocrinology and Metabolism and involved 15 healthy young people, divided into three groups. All three groups ate foods that contained identical amounts of sodium, potassium, calcium, phosphorous, magnesium and protein, but differing amounts of sulfur. The first group (least sulfur) consumed soy products; the second (moderate sulfur) consumed soymilk, texturized soy protein, cheese and eggs; and the third (most sulfur) consumed animal protein from meat and cheese. Those who got their protein from the animal products lost 50 percent more calcium from their bodies than did those who had only soy protein. The soy, egg and dairy people were in the middle. The researchers concluded, "The inability to compensate for the animal protein-induced calciuric response (meaning calcium in the urine) may be a risk factor for the development of osteoporosis."
What is never mentioned when this study comes up--as it does in soy industry spokesperson Mark Messina's The Simple Soybean and Your Health and Earl Mindell's Soy Miracle among other books--is that the 15 subjects spent a grand total of 12 days testing each type of food. This was just enough time for their bodies to react to unexpectedly high levels of sulfur proteins, but not enough time for the body to normalize and handle the sulfur load. Calcium homeostasis is normally well regulated so that increased calcium loss through the urine results in increased calcium absorption from the gut. This adaptive process may fail to occur during short-term studies but the human body is more than capable of adjusting to the sulfur load of real foods, given a proper time frame.
As for the recent study in the July European Journal of Nutrition, the evidence that soy isoflavone supplements stem bone loss was based on the results of bone density tests. These tests measure bone quantity but not quality, and fail to acknowledge that thin bones can be strong, flexible and healthy while thick bones can be brittle and friable. If soy isoflavones, in fact, stop bone resorption, the result could be chalky big bones that crumble. This is exactly what's happening with some women whose bone mass has been "preserved" with drugs like Fosamax.
The Vitamin B6 Connection
Sulfur is not a problem provided our levels of vitamin B6 are adequate. Pyridoxal-5-phosphate (the most active form of vitamin B6) is the coenzyme for cystathionine synthetase, the enzyme needed for proper conversion of sulfur-containing amino acids. This nutrient is short supply in most American diets. The most obvious solution is to optimize vitamin B6 levels, not to cut back on foods containing sulfur. Best and most available sources of vitamin B6 are raw animal foods, such as raw meat, raw milk and raw cheese.
The fallacy of most other studies linking sulfur-rich animals foods to high calcium excretion is equally easy to find. The majority of the experiments feature overdoses of the isolated amino acids methionine, cysteine and cystine without providing adequate levels of vitamin B6 and the extra hydrochloric acid needed to process this high amino acid load. Notably, people and animals fed real food have not experienced the same problems, so cutting back on sulfur-rich foods is not the solution to osteoporosis.
Malnutrition in Children
Evidence that soy milk does not promote healthy bone growth in children has even begun to appear in the mainstream press. A May 8 Newsweek article entitled "Does Milk Hurt Kids?" warned readers that children given rice and soy-based milk substitutes were showing rickets and other signs of malnutrition once found almost exclusively among the famished in third world countries. Soy milk, of course, contains phytates, which block the proper absorption of calcium, zinc and other minerals needed for proper bone growth.
Although calcium supplements are added to soy milk to compensate for theft by phytates, the cheap powders are hard to absorb or not swallowed at all because of the powder's tendency to either clump at the bottom or stick to the walls of the container.
Commercial soy milks also contain vitamin D2 (ergocalciferol), the ineffective vegetarian form of vitamin D that offers few of the benefits of true vitamin D3 (cholecalciferol) and has been linked to hyperactivity, coronary heart disease and allergic reactions. Even the cheapest dairy milks sold in supermarkets use vitamin D3, but soy milk manufacturers use D2, the only form accepted by soymilk-swigging vegans.
Finally, soy milk is high in sugar, a well known bone hazard. Most brands add between 1 teaspoon and 1 tablespoon per glass.
Vitamin K and the Bones
To date, only one study convincingly suggests that soy might prevent osteoporosis, which was published in Journal of Nutrition, May 2006. It pertains, however, to natto, a fermented Japanese soybean product rarely sold in the US--and the bone building probably doesn't come from the miracle bean itself. Rather, natto is high in vitamin K, a fat-soluble vitamin that is manufactured by the bacteria involved in the fermentation process. Vitamin K is crucial for bone health and conspicuously absent from soy milk or any other modern soybean products. But don't expect to find natto in the stores anytime soon as few Americans are likely to appreciate its sticky coat, cheesy texture, musty taste, sliminess and pungent odor. Butter and lacto-fermented foods like sauerkraut are the best sources of vitamin K in western diets.
The Thyroid Risk Factor
Other than the vitamin K found in natto, soybean products have little to offer our bones and much to harm them. More than 70 years of studies link soy to thyroid problems, manifesting most often as hypothyroidism with its symptoms of weight gain, fatigue, malaise and lethargy. Low thyroid is not only a leading cause of midlife misery but a known risk factor for osteoporosis. Yet soy phytoestrogens are widely marketed to midlife women.
Not Good for Menopause Either
The US Agency for Healthcare Research and Quality issued a report last fall in which it concluded that the studies on soy and menopause are inconsistent, contradictory, of poor design and too short duration to warrant any meaningful conclusions from them. Furthermore, the Israeli Health Ministry, French Food Agency and Cornell University have warned that women diagnosed with--or at risk for--breast cancer should exercise caution in terms of soy consumption. The soy industry has responded by switching its message to midlife women--trumpeting claims that soy is at least the answer to the osteoporosis epidemic.
While it's true that researchers have found estrogen receptors in bone, soy phytoestrogens won't reliably activate them. In any case, the key hormone for bone health is not estrogen but progesterone. In that American women most often suffer from estrogen dominance and progesterone deficiency, soy protein powders or phytoestrogen supplements aren't likely to help.
Not So Friendly Skies
Fly United Airlines and you'll be offered a "Savory Snack Mix" that bills itself as "A premium blend of pretzels, BBQ corn sticks and garlic & onion soy nuts." And that's not all folks. The complete ingredient list is as follows:
Pretzels: Enriched flour (wheat flour, malted barley four, niacin, reduced iron, thiamine mononitrate, riboflavin and folic acid), salt, corn syrup, partially hydrogenated soybean oil, baking soda and yeast.
BBQ Corn Stick: Corn masa, soybean oil, seasoning (salt, sugar, chili pepper, spices, natural flavor, paprika, maltodextrin, garlic powder, onion powder, natural smoke flavor, oleoresin paprika, Red #40).
Onion Garlic Soybean: Soybeans (roasted in canola oil), salt, onion, garlic, sugar and no more than 2% silicon dioxide added to prevent caking.
Why the pretzels and corn sticks are manufactured with soybean oil but the soybeans with canola oil is not explained.
Soy and Thyroid Function
While our government continues to deny that soy is a cause of endocrine problems, a report from the Institute of Endocrinology in the Czech Republic correlates markers of thyroid disease with soy phytoestrogen levels. High levels of soy isoflavones in the blood of 268 children without overt thyroid disease correlated with high levels of thyroglobulin autoantibodies and small thyroid gland size. While "only modest association was found between actual phytoestrogen levels and parameters of thyroid function," the researchers warned that "even small differences in soy phytoestrogen intake may influence thyroid function," ending with the disclaimer, "which could be important when iodine intake is insufficient" (Clin Chem Lab Med. 2006;44(2):171-4). Another recent report found that "Soy formula complicates management of congenital hypothyroidism." Infants fed soy formula were found to have prolonged increase of thyroid stimulating hormone (TSH) compared to infants fed non-soy formula (Arch Dis Child. 2004 Jan;89(1):37-40).
FACTORY FARMING IN CHINA: Surprisingly, one of the biggest importers of soy is China, but the reason is not because the Chinese are eating more soy. No, with new-found prosperity, the Chinese want more chicken and pork--consumption of meat has increased threefold in the past decade. Chinese farmers traditionally fed their pigs and chickens with leftover food and ground grains. According to the Wall Street Journal, "The old method wasn't fit for mass production, which is why farmers are moving to soybean-based feed." The Chinese are also using soybeans to feed fish and make soybean oil, ensuring that the Chinese will no longer get the nutrients they need from animal fat (August 21, 2006).
LOST HIS COOL: "Is this the beginning of the end for the 'soy revolution'?" asks journalist James Nestor in an article that appeared in the San Francisco Chronicle (August 13, 2006). After listing all of soy's problems and quoting from The Whole Soy Story by our own Kaayla Daniel, PhD, Nestor shows that super-smooth soy promoter, Dr. Mark Messina, is losing his cool. "Shame on you for even talking to her!" snaps Messina. "Here is a person with a mail-order PhD. . . trying to promote a book of quasi-science. . . that's just , it's, reprehensible!" In fact, Union Institute and University, where Daniels received her PhD, meets the gold standard of regional accreditation. Messina's attack represents a new tactic, which is decidedly a step up for our soy campaign--the soy boys have moved from ingoring Daniel's book, hoping it will go away, to slandering her rather than debate the issues. Last fall, Messina refused an invitation by editor Larry Dossey to debate her in the magazine Explore. "It's the thousands of positive trials that never get attention," Messina whines, "only the ones that are different from everything else that the media clings to." Translation: Soy promoters aren't happy that the public is hearing the other side of the story after years of favorable press for the soybean.
NEW PRODUCTS: Pepsi has introduced a Tropicana orange juice product containing "cholesterol-lowering" plant sterols, similar to the isoflavones in soy. These sterols are actually a toxic waste product of the lumber industry; they cause female characteristics in male fish. Ma-Me! The Tasty Snack Bean made its national debut at Natural Products West in February. A product of Bright Future Foods, the edamame snack is packaged in a down-home brown paper bag and is marketed as "high in fiber, with zero trans fat and zero cholesterol." A portion of the profits from Ma-Me! will go to the Bright Future Adoption Foundation, established by the company CEO to provide counseling and financial grants to prospective adoptive parents. Will promotion of soy foods be part of that counseling? Just asking.
This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Fall 2006.
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