Posts Tagged "soy isoflavones"

More on soy? Oh joy!!

Posted by on Apr 15, 2011 in hot flash, nightsweats | 2 comments

A close friend of mine wrote me the other day to tell me about an article she had seen. In it, the author claims that using soy sauce will help to alleviate hot flashes. However, the author neither backs this claim with any evidence or provides information on how much soy sauce you’d need to obtain the minimal level typically associated with some sort of reduction in menopausal symptoms.

Because there’s a ton of bad information floating around the interwebz, I wanted to break it down for you, right here and now. I also encourage you to peruse the archives because I’ve written a ton of posts on soy isoflavones.

Here’s what we know thus far about soy and soy isoflavones:

  • Soy isoflavones are plant-based compounds that are believed to mimic the action of natural estrogen in the body. Therefore, researchers have been dissecting and studying the properties of soy for years in order to determine if this alternative to hormone replacement can help alleviate hot flashes and night sweats, and possibly even promote bone health in menopausal women.
  • The deeper researchers delve into the properties of soy, the more they are learning. For example, the ratio of the most plentiful soy isoflavones, i.e. daidzein and gensistein, are important, and a metabolite of daidzein called S-equol appears to be the most potent in terms of preventing flashes and sweats.  S-equol  is produced in the gastrointestinal tract however the ability to actually manufacture it depends on the presence of certain microflora. Consequently, only 30% to 60% of individuals are actually able to produce S-equol on their own (although this figure is believed to be higher among Asians and vegetarians).
  • Studies that have examined the role of a soy-based diet, mostly among Asian populations, typically focus on four main foods that are rich sources of soy isoflavones: tofu, miso (fermented soybean paste), natto (sticky, fermented soy food rich in vegetable protein) and fried tofu. Soy sauce and soy oil do not contain isoflavones! Therefore, using either in cooking will not prevent hot flashes or night sweats.
  • In a more recent review of soy products published in the American Journal of Epidemiology, researchers evaluated the dietary habits of 1,106 Japanese women between the ages of 35 and 64 over six years to determine a possible association with hot flashes or lack thereof. All participants were asked to record what they were eating as well as the serving size; included were nine specific soy products (miso soup, tofu, deep-fried tofu, fried bean curd, dried bean curd, natto, houba miso, soy milk and boiled soybeans).

The findings? There was an inverse association between eating soy and hot flashes – those women eating the greatest amount of soy, i.e. 115.9 grams/day, that contained the greatest amount of isoflavones, i.e. 50.8 grams/day, had the highest amount of protection against developing hot flashes and a 6% lower risk than women who consumed the least amount for developing hot flashes over the course of the study. Moreover, the results were upheld even after researchers accounted for factors such as age, menopausal status and total daily caloric intake. Notably, if soy sauce or oil actually contained isoflavones, an individual would have to consume at least 4 ounces of soy sauce daily to obtain any benefit.

Most importantly, when it comes to soy, even supplements aren’t created equal. If you are going to go that route, speak to a licensed practitioner who specializes in herbal medicine and look for a supplement that notes standardized manufacturing on its label. Simply walking into a drugstore to make a purchase is a sure way to guarantee that skimping on price often means skimping on quality.

There’s a lot more we need to learn about soy before making blanket recommendations. Soy is more complex than researchers originally thought. And a few drops a day? No way!

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Soy. Is it safe?

Posted by on Jan 3, 2011 in diet, herbal medicine, osteoporosis | 0 comments

For years, researchers have been exploring the potential of soy isoflavones — naturally-occurring plant estrogens — for alleviating menopausal symptoms such as hot flashes, atrophy and bone loss. Thus far, certain components of soy, including genestein and S-equol have shown the most promise. However, are they safe?  And, as the adoption of soy as a viable alternative to risk-ridden hormone replacement therapy continues to grow, and women turn to supplements rather than food-based soy, is there anything that they need to worry about in terms of side effects?

Researchers recently evaluated this question in a study of 403 postmenopausal women who took  either 80 mg soy tablets, 120 mg soy tablets or placebo tablet daily for  two years. The particular type of soy isoflavones used were hypocotyl isoflavones, which are a byproduct of soy protein and (very rich in daidzein – the second most plentiful isoflavone in soy. The effects of the supplements were measured at the study’s start, at one year and at the end via blood tests and a well-woman examination (i.e. mammogram, pap smear, x-rays to measure bone density). A smaller group of women also had ultrasounds done to determine any possible effects on the lining of the uterus or development of fibroids.

Although the primary goal of the study was to determine the effects of this type of soy supplement on osteoporosis and bone loss, the researchers discovered that taking soy supplements during this time period did not present any major risk to health and did not affect thyroid function. Although one participant developed breast cancer during the study and one, endometrial cancer, 1) utrasounds in the subgroup of women who received them did not show any uterine thickening and 2) the rate of cancer development in this study, only two women over a two year time period, was considerably lower than statistically likely in a general population of women. Both of these factors support the contention that soy isoflavones are not likely to promote either cancers.

So, is soy safe over the long-term? It appears that it is. HOWEVER, bear in mind that the type of soy used in this study is are very different that the type that is commonly sold over the counter, which commonly contain higher percentages of genistein, the most plentiful isoflavone component in soy.

And what about osteoporosis? This particular paper did not address those specific results, although others have. Thus far, the results have been mixed. However, this particular study, better known as OPUS (Osteoporosis Prevention Using Soy)is one of the largest and most comprehensive to date and those findings are likely to come to light soon.

In the interim, if you are going to be taking soy in supplement form, be mindful that your exposure is likely to be as one to four times that a typical Asian diet and as much as 100 times that of a typical Western diet. While these level do not appear to be harmful, herbal and plant medicines are not without risk so as always, the rule of thumb is be vigilant and speak to a health practitioner first.

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Newsflash: hot flashes and soy…more on genistein

Posted by on Dec 17, 2010 in hot flash | 0 comments

There’s some exciting news on the soy isoflavones front: for the first time, researchers have shown that a synthetic formulation of genistein, a plant-based estrogen component of soy, may actually reduce both the frequency and severity of hot flashes. Genistein is an interesting isoflavone, in that studies have linked it to some truly potentially important benefits, including preventing or reducing heart disease risk and attenuating bone loss in menopausal women. While the verdict is still out on its role in these conditions, it does appear to influence hot flashes and only in the best way possible! Moreover, this is the first time that a synthetic formulation has shown to have some degree of benefit in this regard.

Granted, this is a small study of only 84 menopausal women, 40 of whom took synthetic genistein for 12 weeks and 40 who took a sugar placebo tablet. The results? By the study’s end, women taking 1, 30-mg capsule daily reduced the number of hot flashes by half (51%, from about 10 per day to 5 per day) and also experienced significant declines in how long they lasted. The synthetic formulation, which was standardized, was also shown to be safe and did not detrimentallly impact the lining of the uterus. Notably, however, the researchers did note that there are not enough data to recommend isoflavones to women who’ve had breast cancer or at high risk for developing, even though current data suggest that exposure does not adversely affect breast tissue density or cancer cell proliferation, meaning that it is likely that with more study, they will ultimately prove safe for use in breast cancer patients.

Your key take-away is that there may be a viable option for women who are flashing but want to stay away from hormones. However, this is what we still need to know:

  • Will genistein work on larger groups of menopausal women?
  • Is formulation important?
  • Is the 30 mg dose the lowest dose that will confer these sort of benefits?
  • Are there any other factors that these women had in common that might be influencing outcomes?

As with any novel data like these, it’s great to be cautiously enthusiastic. Stay tuned!

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Soy! Everything you wanted to know. Or should.

Posted by on Sep 20, 2010 in hot flash, HRT | 6 comments

Confusion about soy abounds. Does it help hot flashes, improve bone health or prevent heart disease by lowering cholesterol? Or it is no more effective than placebo?  Does its effectiveness rely upon the ratio of certain isoflavones — the plant-based estrogen-like components, which in soy include  genistein (50-55% of total isoflavone content of soy), daidzein (40% to 45% of total isoflavone content) and glyceitein (5% to 10% of total isoflavone content) — or is the metabolite S-equol the only component that will yield estrogen-like benefits without negative health risks?

Are you perplexed? I sure am, which is why this particular post may be a bit to scientific for a few and too long for others. however, it’s important to understand some of the reasons why soy continues to intrigue, baffle and well, show differing results in terms of benefits for menopausal symptoms. So I encourage you to bear with me.

I’ve written previously that there are several key reasons why researchers have yet to make any any definitive conclusions about soy during menopause, such as poorly designed studies, small number of study participants, wide range of ages and years from menopause, and the fact that the pros and cons of an agent or strategy are not being studied for a long enough period of time. In other cases, there is an inconsistency in the soy preparation being studied and the ratio of isoflavones may differ; alternatively, researchers have not accounted for the presence of other isoflavones in the diet, which may influence results.

Does a new study that appears in the advanced online edition of Maturitas journal, comparing low-dose hormone therapy to soy powder in women with hot flashes, offer any anything more definitive or different than what’s gone before?


The 16-week study enrolled 60 women between the ages of 40 and 60, all of whom had had their last period at least 12 months, had the same frequency of hot flashes (more than 8 per 24 hours), had not used any hormonal treatment in the 6 months leading up to the study period, and were not currently using any drugs that lower blood fats, treat diabetes, taking other soy-based products or using herbal supplements.

Women participating in the study were randomly assigned:

  1. low-dose hormone therapy (a Activelle ®tablet daily, better known as Activella® in the US) plus a placebo powder or
  2. 2 portions daily of dietary soy supplementation powder (comprising 45 mg isoflavone per dose) plus a placebo tablet, or
  3. 1 placebo tablet/2 portions placebo powder.

All women were first screened  for  current hormone levels, reproductive history, age at menopause, time since menopause, medication use and cigarette/alcohol consumption. During the study, they were asked to use a standardized scale to evaluate menopausal symptoms (hot flashes, heart discomfort, sleep, and muscle and joint problems) mood (depression, irritability, anxiety, physical/mental exhaustion) and sexual problems, bladder problems and vaginal dryness.

The results?

Both hormone therapy and soy supplementation were associated with significant improvements in hot flashes and joint/muscle pain (which declined by about 45.6% in the hormone group and 49.8% in the soy group) and in vaginal dryness (which decline d by 38.6% in the hormone group and 31.2% in the soy group) compared to women who took placebo. Improvements in mood scores were consistent between the three groups, indicating that other factors, such as caring and attention by medical practitioners throughout the study, may have played some role in wellbeing. Moreover, both treatments were considered safe with few side effects.

These results are quite promising, as they indicate that soy may indeed, offer an alternative to hormone therapy in menopausal women seeking relief. However, it’s important to consider the following:

  • Like many of its predecessors, the study is a small one.
  • The study length was short, lasting only 16 weeks, which some critics might say is too short a time period to elicit a satisfactory clinical response.
  • The researchers did not analyze whether or not the women actually took the drugs or soy consistently, and relied on their self-reports.

On the other hand:

  • The study followed strict Western scientific guidelines and the women and the researchers did not know who was taking what.
  • Symptoms were measured using a common quality of life scale whose goal it is to diminish errors by healthcare practitioners when analyzing results of questionnaires. This particular scale, better known as the MRS, is widely used and allows researchers to evaluate symptoms and treatment over time.

There has been a lot of criticism geared towards alternative treatments, such as acupuncture, herbs and Chinese medicine, as being shams, especially because there is no evidence supporting their use for addressing troublesome menopausal symptoms. Others will claim that the placebo effect is at play, i.e. a situation in which symptoms are relieved by an otherwise ineffective treatment due to expectations or beliefs. However, the researchers of this particular study point to the placebo effect in studies comparing estrogen to placebo, demonstrating for example, a 75% reduction in hot flashes among hormone users compared to a 57% reduction in hot flashes among women taking placebo.

The most important conclusion to be drawn is that there is early evidence that soy supplementation may be as effective as low-dose hormonal therapy in relieving certain vasomotor symptoms and possibly, vaginal dryness. We need more studies like this one, enrolling larger numbers of women, in order to definitively demonstrate benefit. Dollar for dollar, the monthly difference between the two treatments may only be about $30.  Yet, this is one of the first studies I’ve seen that followed enough rules to quiet the rioters. And that alone, is worth the price of admission.

Stay tuned. The fat lady hasn’t sung her soy aria as of yet.

[Special thanks to Reuters Health Executive Editor Ivan Oransky, for your continued support of my mission to provide timely, evidence-based information on menopause and midlife to my readers.]

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Wednesday Bubble: the soy controversy

Posted by on Apr 7, 2010 in bone health, emotions, hot flash | 0 comments

Do they or don’t they?

Soy isoflavones have been touted as beneficial in everything from improving body composition and lowering breast and colorectal cancer, to addressing menopausal hot flashes and moods. You can read about some of these findings on Flashfree. This week, Reuters Health reported that eating foods rich in soy protein (i.e. 25 grams of soy protein and 60 mg isoflavones) daily did not provide favorable responses from blood fats, implying that soy has little benefit in terms of lowering cholesterol levels and in turn, promoting heart health.

Are you confused yet?

Increasingly, women are turning to soy and other compounds as alternatives to estrogen and hormone replacement therapy, which mounting evidence shows can be associated with a broad range of risks including  increased breast, lung and ovarian cancer to heart disease. And yet, findings from clinical trials examining soy are often contradictory, making it difficult to come to any firm conclusion about its benefits.

What’s the problem? Well, researchers say that part of the problem is poorly designed studies, small number of study participants, wide range of ages and years from menopause, studies that don’t examine the pros and cons of an agent or strategy for a long enough period of time (i.e. longer than a year). In other cases (as I’ve argued previously), the study design does not account for certain factors that are critical to a therapeutic strategy, for example, the opportunity to clearly focus an intervention so that individual factors are accounted for (this was borne out by findings from a trial that examined and provided evidence for the role of acupuncture in easing hot flashes).

There’s good news though! Researchers finally appear to be getting their act together on the soy fron. They’ve announced that they are conducting a well-designed, large trial of soy phytoestrogens. Called  SPARE (Soy Phytoestrogens as Replacement Estrogen), this new study will be looking at the effects of 200 mg soy versus sugar tablet daily — namely on bone health and symptoms —  in 248 menopausal women over a two- year period. They will also be taking daily calcium carbonate plus vitamin D (in ranges of 500 mg to 1000 mg calcium and 200 to 400 IU vitamin D, depending on previous intake).

The study is specifically geared towards looking at spine bone density, but will also be looking at hip density, thyroid levels, menopausal symptoms, mood changes, depression, and quality of life, as well as any changes in blood fats. Study participants are between the ages of 45 and 60 and are within five years from menopause. What’s more, the researchers have also included a large percentage of hispanic women, which allows them to focus on how soy affects this minority group (Notably, the large multiethnic population of women in this study includes Asians, Blacks and Caucasians.)

The researchers say that they hope that the results of SPARE will provide a range of information that is especially relevant to Boomers reaching menopause. They also note that the dose of soy isoflavones being studied is much larger than what’s been studied in previously and are roughly twice that typically consumed in the Asian diet.

I realize that this post is pretty scientific. But what makes it most relevant is that it appears that researchers are finally starting to design studies that might actually show benefit of some of the alternative strategies we have available to us on the market. For those of you who insist on calling these alternatives “snake oil,” all I can say is ‘stay tuned.’

This bubble might finally be shattered; perhaps all that is needed is a better understanding of what it needs to test these substances appropriately.

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