Search results for genestein

Newsflash: What’s the latest on soy?

Posted by on Oct 17, 2014 in hot flash | 0 comments


Does it or doesn’t it? That is, does soy  relieve menopausal hot flashes or not?

The evidence has been less than definitive however, researchers now say that trials examining the benefits or lack thereof of soy in attenuating symptoms may have been negatively affected by significant limitations, such as failing to recognize treatment timing and duration on effectiveness, small numbers of women in the studies and wide variations in how much hot flashes were reduced with treatment. And so, they took another look at the data using a new model, one that allows scientists to actually compare different treatments and evaluate the effectiveness of different factors, including dose, duration of treatment and formulations. This is an important method of analysis and one that could truly be considered a game changer. They say that their findings, published online in the British Journal of Pharmacology, will provide “information for deeper understanding of the efficacy of soy isoflavones on menopausal hot flashes.”

I am going to skip over the science mumbo jumbo and get right to the meat of how they came to their ultimately conclusions:

  • Findings were based on an analysis if 16 studies published between 1998 and 2012 enrolling over 1700 subjects.
  • In terms of duration, the effect of soy isoflavones were studied for anywhere from 4 weeks to two years, with a median of 12 weeks.
  • In these studies and vis a vis modeling, soy isoflavones were compared to both placebo and estradiol, the latter in terms of how long it takes to reach effectiveness. This last point is important.

And now, the result.

While the effect of isoflavones on hot flashes was superior to placebo, the researchers still observed a relatively strong placebo effect at play. Importantly, however, the placebo effect at play was even higher in trials examining estradiol and hot flashes. The reason? Apparently, women might have lower expectations when it comes to alternative therapies like soy. Yet, there was still another important finding that was teased out by this new modeling:

Soy isoflavones require at least 13.4 weeks to reach at least half of their  full level of activity in the body. In comparison, estradiol only needs about 4 weeks. So, when you do the math, at four weeks (which is the usual length of most clinical trials of this nature), estradiol has reached 80% of its peak activity level and soy isoflavones, only 47%. By 48 weeks, soy isoflavones catch up.

Additionally, as I’ve written time and again, there are different components of soy with differing levels of effectiveness. Genestein is the strongest and yet, only three studies specifically looked at soy agents that contained genestein only. So, there was no way for the researchers to break down the findings by components.

Overall, the key takeaway is that it takes longer for soy to reach maximum effectiveness than it does estrogen. So, if we are going to quantify value moving forward, it’s important to account for this significant distinction.

When it comes to soy, it may simply be that slow and steady wins the race.

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Posted by on Apr 9, 2012 in hot flash | 3 comments

It’s been a rough ride for soy, with studies often at odds regarding its effectiveness in ameliorating or preventing hot flashes. Some reviews have shown that soy isoflavones, in particular S-equol and genistein can alleviate hot flashes while others fail to finding anything conclusive. Still, the original observation that Japanese women appear to suffer less frequently from hot flashes and have a high consumption of soy isoflavones has led researchers to keep trying to tease out the benefits of soy.

I am glad that they have. In fact, in a study published online in Menopause  just a few weeks ago, researchers reported that an extensive review of 19 scientifically sound trials has shown that soy isoflavones are significantly more effective than placebo in reducing both the frequency and severity of hot flashes.

Here’s what you need to know:

  • 19 trials were included for analysis and a variety soy isoflavone supplements in different doses ranging from 30 mg to 135 mg daily were studied. Some of these were natural formulations and others, chemically synthesized to match key ingredients believed to have a health effect.
  • Hot flash severity and frequency were examined in women that were either premenopausal, perimenopausal or menopausal (i.e. postmenopausal) although definitions used to define this group differed between studies.
  • The number of women in these studies totalled over 1,200.

The results showed that taking 30 to 80 mg soy isoflavones daily for 6 months to a year significantly reduced the frequency of hot flashes by roughly 17%. Moreover, the 10 trials analyzed for hot flash severity showed a significant reduction by as much as 30%. In both cases, these figures increased depending on how the researchers teased out and analyzed the data.

The researchers say that even though there is a common perception that results from soy trials have been mixed, there has been a “consistent and clear pattern in favor of isoflavones over placebo” when properly plotted on a graph. Moreover? The scientifically designed studies that were included in their analysis helped to insure that all populations, including women with breast cancer, were included. Additionally, they analyzed studies that were as short as 6 weeks in duration, namely to determine if women with cancer not receiving treatment would respond the same as healthy women. Additionally, there is some indication that the effectiveness of soy actually increases over time with continuous use.

What about the type of soy isoflavone? This review actually shows that genestein is more effective than daidzein for alleviating hot flashes.

The key take away is that for women who don’t want to use hormone replacement or are ineligible to do so, there is a scientifically proven effective alternative: soy. And while soy may disturb the GI tract in some women, it is actually quite safe, even among women with breast cancer.

So far, so good. The next step is to determine which factors matter most to gain benefit, e.g. dose, formulation, hot flash frequency and how long a woman needs to remain on treatment.

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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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