"How to Convert Into an Equol Producer"
Menopause is characterized by a decrease in estrogen, which
triggers the uncomfortable symptoms of hot flushes,
night sweats, sleep disturbances, and vaginal dryness.
"Among these menopausal symptoms, hot flushes
(also known as hot flashes) are reported by many women
to be the most bothersome."
I already summarized the available evidence on the role
of soy phytoestrogens to alleviate those symptoms.
Here's the latest meta-analysis.
Although the balance of evidence point to soy benefits,
the individual study results are all over the place.
Yes, some studies show 20, 30, even 40% better than control,
but some showed no effect.
This is something that's been noted by the professional
societies, like the American College of OB/GYNs.
Yes, these supplements may work,
but the evidence is so inconsistent.
This may be partly because the supplements used
were extracted from different parts of the soybean.
Maybe it would be better if they just used
soy foods rather than supplements.
The dosing would be about two servings of traditional soy foods
a day, like two cups of soymilk, which is what you see
older women in Japan doing, who have some of the lowest
reported rates of hot flashes in the world.
But even the studies on soy foods, as opposed
to supplements, have had conflicting results.
Why all the inconsistency?
It may have to do with our gut bacteria.
People who eat foods made from soybeans,
which have these health- promoting isoflavones,
tend to have lower rates of a variety of chronic diseases.
So we can garner this protection
by eating more soy foods, right?
Well, it may be a little more complicated than that.
There are certain gut bacteria that can convert isoflavones
in soy into a potentially
even more beneficial compound called equol.
Not all individuals can make this conversion, though,
because not all individuals have the specific types
of good bacteria in their gut that do it.
So there's two types of people in the world, equol producers
and equol nonproducers, depending on their gut flora.
And so this may help account for the variations
in health benefits we see in clinical studies.
It may help explain why some people seem to benefit
from soy more than others.
For example, in the study I covered before
about how soymilk appears to prevent bone loss in the
spines of postmenopausal women, if you split
the women into equol producers and nonproducers,
soy did work in nonequol producers,
but seemed to work even better in the women
whose gut bacteria is able to take the soy to the next level.
The more equol Japanese women make from the soy
they eat, the fewer menopausal symptoms they may have.
Some studies suggest equol-producing men
may get less prostate cancer.
If that's the case, maybe we should look into improving
the intestinal environment to enable equol production.
Only a minority of the Western adult population
is able to produce equol, though almost every
other animal species appears to produce it, no problem.
In fact, that's how it got its name.
It's named equol because it was first discovered in horses.
But, interestingly, horses during the summer, not winter,
because that's when their gut bacteria had access
to the phytoestrogens in clover;
that was our first clue equol was made from plants.
If you're not Mr. Ed, though, can you take someone
who doesn't make equol and convert them into an equol producer?
Certainly you can do the reverse: excessive use
of antibiotics can wipe out your good bugs,
but how can you acquire the right good bugs?
Suggested strategies include dietary alteration or probiotics.
The standard probiotic regimens don't seem to help,
so how about dietary alteration?
Well, about half of Japanese and Korean individuals
can produce equol, but only as low as 1 in 7 Americans.
Maybe it's because more soy is eaten in Asia?
That would make sense; if you eat a lot of soy, you may foster
the growth of bacteria in your gut that can digest soy.
But a month of soy isoflavone supplement exposure
didn't seem to convert nonproducers into producers.
But just two weeks of drinking 3 glasses of soymilk a day
was able to convert 3 of 6 women into producers.
For example, this woman started out not making any at all,
or maybe a little bump between hours 50 and 60,
but after two weeks of drinking soymilk,
when they had her drink some more, she had nice equol spikes.
It didn't work for all women though.
And when they tried the same experiment in men, nothing happened.
Hmm, back to the drawing board.
Is there any group of Westerners
that have high equol production rates that may offer a clue?
Vegetarians have among the highest equol production rates
ever recorded, more than 4 times as likely to be
equol producers as their nonvegetarian counterparts.
The question is why?
They don't think it's because of the soy, given the conflicting soy data.
Maybe it's because they're eating more prebiotics like fiber?
Or maybe dietary fat intake decreases the capacity
of gut flora to make equol,
or maybe it has something to do with cholesterol intake?
Analyzing the diets of equol producers, they do seem
more likely to be eating more carbs, plant protein, and fiber,
but researchers have tried giving people
fiber supplements along with soy, but that didn't seem to work.
Whatever it is about those eating plant-based diets,
they may soon be the only remaining majority
equol producers, as Asian populations
continue to Westernize their diets.