Posted on 08/25/2004 10:27:59 PM PDT by neverdem
When Eileen Haraminac, 53, of St. Clair Shores, Mich., began experiencing symptoms of menopause - intense hot flashes, as many as 15 a day, waking in the middle of the night drenched in sweat and fitful sleep - she knew she needed help. But she was also aware that there were problems with hormone therapy, the standard treatment for menopause symptoms. Studies have linked it to a higher risk of heart disease, stroke, blood clots and breast cancer.
This concern, combined with Mrs. Haraminac's general philosophy about medications - avoid them if possible - persuaded her to try a more natural remedy. She introduced soy into her diet, hoping that its high level of phytoestrogens, plant-based estrogens, would offer relief. She cooked with tofu, made soy smoothies, drank soy milk and ate edamame, young soybeans. She also took a supplement that contained 55 milligrams of isoflavones, a purified form of the phytoestrogen in soy.
"Since I started using soy, I've had fewer hot flashes and they're mild," Mrs. Haraminac said. "The symptoms have tempered down a bit."
Anecdotes like Mrs. Haraminac's are not uncommon. But the effectiveness of soy in relieving the symptoms of menopause, or in improving health in any way, is unproven. And while some experts tout soy as a cancer preventative, others say that for postmenopausal women, consuming soy in large doses, especially in isoflavone supplements, may elevate the risk of getting breast cancer or pose other health risks.
There have been no double-blind controlled studies, the gold standard in scientific research, looking at the safety of soy in humans. And the existing research has produced conflicting results, providing little guidance and creating a heated debate among experts.
"People feel very strongly about this issue because there are not many other dietary compounds which could potentially be beneficial in terms of preventing breast cancer and other diseases," said Dr. Leena Hilakivi-Clarke, an oncology professor at Georgetown University and a leading expert on nutrition and cancer. "But they look at the results of studies from their point of view and ignore results that don't support their view."
The question of soy's health benefits or risks has become more acute as consumption of soy and soy products increases, particularly among women seeking a substitute for hormone therapy. Sales of soy foods soared in the late 1990's, and increased 44 percent since 2001, reaching $3.9 billion last year, according to Soyatech and Spins, two market research firms. Curiously, sales of supplements dropped 55 percent during the same time, a decline that may reflect both women's concerns about possible health risks from supplements and the growing availability and appeal of soy foods, said Peter Golbitz, president of Soyatech.
"Consumers have realized that they can get isoflavones from a glass of soy milk, there are more soy snacks available, and people don't have to take a supplement - they can go out and eat it," Mr. Golbitz said.
Despite the unsettled state of the research, the Food and Drug Administration is reviewing a request by Solae, a soy food company, for permission to make the claim on its food products that soy prevents some cancers. In 1999, the F.D.A. approved a health claim for the cholesterol-lowering properties of soy.
Yet last month, a rigorous study published in The Journal of the American Medical Association found that isoflavones did not improve cholesterol levels, cognitive function or bone mineral density in postmenopausal women who took them for a year.
In studies, soy supplements have been found to reduce the severity of hot flashes by only about 10 to 20 percent, after accounting for the placebo effect, a significant factor in treatments for menopause. Women taking hormone therapy have found their hot flashes reduced by about 60 percent.
Still, both the American Menopause Foundation, an education and advocacy group, and the North American Menopause Society, a medical group, support the use of a moderate-dose soy supplement for menopause if other lifestyle factors are ineffective.
The most important issue is what connection, if any, there is between breast cancer and the estrogen in soy. The big worry is that by consuming large amounts of soy, women who are at high risk for breast cancer, who have an undetected breast cancer or who are survivors at risk for recurrence are exposing themselves to estrogen that might promote certain breast cancers. A related concern is that soy supplements may somehow interfere with tamoxifen, an antiestrogen drug taken by women to help prevent breast cancer.
But the effect of the estrogen in soy on breast cells is poorly understood. Some studies, for example, those of Dr. Bill Helferich, a nutrition professor at the University of Illinois, suggest that the estrogen can cause breast cell proliferation, and potentially tumor growth. Dr. Helferich fed isoflavones to mice, which made their tumors grow more aggressively.
His work has been criticized, though, because he used mice whose ovaries were removed, and therefore had almost no estrogen, even less than a postmenopausal woman would have. Without the body's estrogen competing for receptor sites on breast cells, the estrogen in the isoflavones, called genistein, locked on, and made the tumors grow.
Other studies suggest that the estrogen in soy is weak, and so can prevent tumor growth, working, in fact, the way tamoxifen does. For example, Dr. Jin-Rong Zhou, a surgery professor at Harvard, found that isoflavones prevented tumor growth in mice. In his studies, he worked with mice whose ovaries were intact so they had higher levels of circulating estrogen than a postmenopausal woman has. In this model, genistein competed with the body's estrogen for the receptor sites, and in the end, less estrogen attached to breast cells, and the tumors did not grow.
But neither Dr. Helferich's nor Dr. Zhou's research model mimics the postmenopausal woman perfectly.
Meanwhile, no study in women has shown an increased risk of breast cancer among those taking soy.
Epidemiological studies from Japan have found that women who eat soy throughout their lives have slightly lower rates of breast cancer than those who do not, and that Japanese breast cancer patients have a higher survival rate than Westerners.
But many of these studies were designed to look at other questions, not the relationship between soy and breast cancer, and experts point out that other diet, lifestyle and genetic factors may be at play in the lower cancer rate. In their view, these studies do not provide evidence that eating soy helps prevent cancer.
"When we specifically looked at Asian countries, there was a 10 percent reduction in risk, and it was not significant," Dr. Hilakivi-Clarke said.
Also, the Japanese studies were done on women who had eaten soy since they were babies. Many were exposed while in the womb. Because of this, a popular theory is that early exposure to soy may be what protects women from breast cancer.
Indeed, studies have shown that as the breast develops, soy spurs its cells to mature and become differentiated; the more differentiated they are, the less they proliferate, and the less vulnerable they are to cancer.
Dr. Mindy S. Kurzer, a nutrition professor at the University of Minnesota, said that to have a preventive effect, "soy needs to be consumed during the time that the breast is developing, pre-pubertal."
The one point experts agree on is that it is probably safe to eat soy foods in moderation, as people in Asian countries have done for centuries.
"Soy foods are great; they appear to be absolutely safe when consumed at levels consumed in Asia, which is one to two servings a day," Dr. Kurzer said. On average, Asians consume about 15 to 30 milligrams of isoflavones a day, Dr. Helferich said.
But in the United States, a woman could potentially consume 75 to 80 milligrams a day, through products like soy energy bars, chips and enriched cereal, as well as soy milk and tofu. In addition, the concentration of isoflavones in some supplements has increased. Some have as much as 300 milligrams, although most have about 45. Some supplement companies have also added isoflavones to other nutrients directed at menopausal women, among them calcium or herbs like black cohosh, which also contain phytoestrogens.
"We have very little data on supplements, and until we get more data, I wouldn't recommend them," Dr. Kurzer said.
Many experts believe eating soy in moderation is safe for women who have had breast cancer.
As for soy foods, "I fall on the side of the debate that soy foods have been eaten for centuries and it's hard to overconsume them," said Diana Dyer, a cancer survivor and author of "A Dietitian's Cancer Story."
But Dr. Kurzer qualified this. "My recommendation to a woman who has breast cancer is that if she has been consuming soy as part of her diet for a long time at a level of one to two servings a day or less, she can continue that," she said. "But I would not recommend that women who haven't been eating soy start."
ping
Wow they're still bashing soy in the Slimes. I should not be surprised. I'm still waiting for them to wake up to the prescriptions of bioidentical hormones as a better option.
There is definite data that hormone therapy increases your risk of cancer (like the kind that killed my mother), heart attack, stroke, etc.. there is no definite data that soy will hurt you.. especially in moderate amounts.. in fact just the reverse is true.. soy is good for you.. .. I have personal experience with this.. I had some nasty airborne allergies that kept me up nites congested and coughing.. I introduced soy into my diet in moderate amounts and it has reduced my allergy attacks by at least 75 percent... I have a feeling the drug companies are the ones pushing the notion that soy might hurt you because they aren't getting a piece of the pie.
What are bioidentical hormones ?? Would they be safe for someone with breast cancer?
ping
Thanks for the link:)
others say that for postmenopausal women, consuming soy in large doses, especially in isoflavone supplements, may elevate the risk of getting breast cancer or pose other health risks.
I am almost positive that when the government says "in large doses" it is referring to studies it makes by subjecting rats to something like 1000 times the amount that normal person would ingest. That way, it will cause cancer in rats just like any product subjected to such government testing. If somebody wants something off the market just ask the government to do a "rat" test and the results will get the item off the shelf.
Some people with underactive thyroids (hypothyroidism) find that consuming soy products increases the severity of their "hypo" symptoms. A large dose of soy can leave me feeling fatigued for days afterwards. In one thyroid forum, we refer to the inadvertent consumption of soy as "soybatage," because soy is in everything and it's very hard to avoid these days.
I have found this N.Z. soy info site to be persuasive: Soy Online Service.
If you are worried about rogue estrogen check out vrp.com They have two products, I3C (indole-3-carbinol) and BioDim that I take to counteract estrogen. In men estrogen can cause a number of bad effects especially if they are taking a testerone precursor such as androstenadione.
yeah but what is a "large dose of soy"?
There have been a number of studies linking soy baby formulas to thyroid cancers in later years.
What hasn't been linked to cancer? There isn't a drug on the market that is good and safe for everyone. This "cancer link" is used to scare people into discontinuing something or raising a lawsuit issue. Sometimes, people just need to do what they think is good for themselves and not listen to all the negative spin that accompanies just about every aspect of diet. Studies get done because government grants are available and if startling results aren't found it will not look good on the resume to get other grants.
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