You know the feeling you get when you learn something new
about a health problem you’ve been trying to reverse?
Maybe high blood pressure, diabetes, or heart disease.
Well, there’s nothing I like better than bringing you the information
that will help you do just that.
Welcome to the Nutrition Facts Podcast.
I’m your host, Dr. Michael Greger.
There are a variety of unique health issues that women face
that affect their quality of life.
And today we start with one way to treat
one of the most debilitating diseases that women face: endometriosis.
Endometriosis is a major cause of disability
and compromised quality of life among women — a chronic disease
which is under-diagnosed, under- reported, under-researched.
For patients it can be a nightmare of misinformation, myths, taboos,
lack of diagnosis, and problematic hit-and-miss treatments,
overlaid by a painful, chronic, stubborn disease.
Pain is what best characterizes the disease,
pain, painful intercourse, heavy irregular periods and infertility.
About one in a dozen young women suffer,
and it accounts for about half the cases of pelvic pain and infertility.
It's caused by what's called retrograde menstruation.
Instead of the blood going down, it goes up into the abdominal cavity,
where bleeding tissue of the uterine lining can implant onto other organs.
You can have the lesions surgically removed,
but the recurrence rate within five years is as high as 50%.
Now, endometriosis is an estrogen-dependent disease,
so might the anti-estrogenic effects of the phytoestrogens
in flaxseeds and soy foods help, as they appear to in breast cancer?
I couldn't find studies on flax, but soy food consumption may indeed
reduce the risk of endometriosis,
but I couldn't find any studies on treating the disease with soy.
There's another food, though, associated
with decreased breast cancer risk: seaweed.
Seaweeds have special types of fiber and phytonutrients
not found among land plants, so it's not like choosing
to get your beta-carotene from a carrot versus a sweet potato.
If you want these unique seaweed components,
some of which may have anti-cancer properties,
we need to find a way to incorporate sea vegetables into our diets —
anti-cancer properties such as anti-estrogen effects.
Japanese women have among the lowest rates of breast,
endometrial, and ovarian cancers.
They have longer menstrual cycles and lower estrogen levels
circulating in their blood and that may help account
for their low risk of estrogen-dependent cancers.
We assumed this was their soy intake, but the seaweed might be helping as well.
You can drip seaweed broth on human ovary cells that make estrogen
and see estrogen levels drop, because it's either
inhibiting production or facilitating breakdown of estrogen,
and may even block estrogen receptors,
lowering the activity of the estrogen you do produce.
This is in a Petri dish, though, but it happens in women as well.
They estimate that an effective estrogen-lowering dose of seaweed
for an average American woman might be around 5 grams a day,
but no one has apparently tried testing it on cancer patients yet,
but it has been tried on endometriosis.
Three women with abnormal cycles— two of which with endometriosis—
volunteered to add a tiny amount of dried powdered bladderwrack,
a common seaweed, to their daily diet.
It effectively lengthened their cycles and reduced the duration of their periods.
And not just by a little. Check out subject number 1.
A 30-year history of irregular periods, averaging every 16 days,
but adding just a quarter teaspoon of this seaweed powder a day
added 10 days onto her cycle, up to 26 days,
and a half teaspoon a day brought her up to like 31,
nearly doubling the length of her cycle.
And they all experienced marked reductions in blood flow
and a decreased duration of menstruation.
Poor subject number 1 was having periods every 16 days
that lasted 9 days long. Can you imagine?
After 30 years of this kind of craziness, just a half teaspoon of seaweed a day
and she was having periods just once a month and only lasting about 4 days.
And most importantly, in the two women suffering from endometriosis,
they reported substantial alleviation of their pain.
How is that possible? Look at their drop in estrogen levels.
A 75% drop after just a quarter teaspoon of seaweed powder a day,
85% after a half teaspoon.
Now obviously with just a couple women, no control group,
we have to do bigger better studies.
But look when this study was published: more than a decade ago
and not a single such study has been published since.
Does the research world just not care about women?
Millions of women are suffering with these conditions.
Who's going to fund it, though?
That much seaweed costs less than 5 pennies,
so a larger study may never be done.
But with no downsides, I would suggest endometriosis sufferers give it a try.
In our next story,
we look at how oxidized cholesterol found in eggs,
processed meat, and parmesan cheese
can have cancer-fueling estrogenic effects on human breast cancer.
In 1908, the presence of cholesterol crystals was noted
in the proliferating areas of cancers, suggesting that perhaps cholesterol,
in some way, was associated with the regulation of cancer proliferation.
A century later we now recognize the accumulation of cholesterol
as a general feature of cancer tissue,
and recent evidence suggests that cholesterol
may indeed play critical roles in the progression of cancers,
including breast, prostate, and colorectal cancers.
Perhaps that could explain why egg consumption was associated
with increased breast cancer risk.
And indeed, a systematic review of the evidence suggests
that dietary cholesterol intake increases risk of breast cancer,
and the more cholesterol you eat, the higher the risk appears to go.
But why?
One thought is that the prolonged ingestion of a cholesterol-enriched diet
induces a chronic auto- inflammatory response,
and we know that chronic inflammation can lead
to the initiation, promotion, and progression of tumor development.
It's true that sprinkling some cholesterol on white blood cells
in a test tube can trigger the release of inflammatory compounds,
and LDL cholesterol can induce breast cancer proliferation and invasion.
But again that's in vitro, where you can show that like breast cancer cells
can migrate nearly twice as far within a day in a petri dish
in the presence of LDL cholesterol.
But what about in people?
Well, the level of LDL cholesterol in the blood of women
diagnosed with breast cancer does appear to be
a predictive factor of tumor progression.
About two years after surgery/chemo/radiation,
not one of the women in the lowest third of LDL cholesterol levels
had a cancer recurrence.
The same could not be said for women with higher cholesterol.
We know cholesterol can cause inflammation in our artery walls.
Maybe it's also playing an effect on breast cancer initiation and progression?
They speculate that the high cholesterol levels may have a cancer-fueling effect.
And indeed, women with breast cancer
who happen to be taking cholesterol-lowering statin drugs
appear to live about 40% longer before the cancer comes back.
But the data isn't good enough to ensure the drug benefits outweigh the risks,
though lowering cholesterol with diet one may be able to get
the best of both worlds.
But what does that have to do with dietary cholesterol?
Sure, animal studies show that if you feed mice cholesterol
you can accelerate their cancers, but extrapolation to humans
is difficult as dietary cholesterol has limited effects
on blood cholesterol levels in humans.
Thus, dietary cholesterol might just be indicative of a lifestyle
prone to health-related problems, including cancer.
Maybe people are just more likely to chase bacon and eggs down
with a cigarette compared to oatmeal?
It's hard to imagine how dietary cholesterol alone
could promote cancer development.
But that all changed recently with the discovery that 27-Hydroxycholesterol,
a metabolite of cholesterol, can function as an estrogen
and increase the proliferation of most breast cancer cells.
Ah, so it's not the cholesterol itself, but what it turns into in the body.
Scientists have long struggled to understand why women
with heart disease risk factors are more likely to develop breast cancer.
Now, perhaps we know.
The discovery that the most abundant oxidized cholesterol metabolite
in our bloodstream can have estrogenic effects
may explain the link between high cholesterol and the development
and progression of breast cancer and prostate cancer.
Yes, 27-Hydroxycholesterol also stimulates the proliferation
of prostate cancer cells, boosting growth by about 50 percent.
I've explored before the role oxycholesterols may play
in mediating pro-oxidative and pro-inflammatory processes
in degenerative diseases such as Alzheimer's and heart disease,
but now it looks like oxidized cholesterol can play a role
in all three stages of tumor development as well:
initiation, promotion, and then the progression of the cancer.
Not just promoting the growth of breast cancer cells,
but also inducing their invasion and migration,
potentially facilitating breast cancer metastasis
through suppressing anti-cancer immunity,
and then inducing angiogenesis:
helping breast tumors hook up their blood supply.
This is all supported by several lines of evidence
that point to a pathologic role for this cholesterol metabolite.
Yeah, you can feed mice cholesterol,
their oxysterol levels go up and their tumors accelerate.
It also appears to dramatically hasten the spread, or metastasis,
of breast tumors to other organs.
But turning to human breast tissue samples,
they found that more aggressive tumors have higher levels
of the enzyme that converts cholesterol into 27-HC.
In breast cancer patients with estrogen receptor-positive tumors, the 27
Hydroxycholesterol content in their breast tissue is increased overall,
and especially within the tumor itself,
so much so that circulating oxysterol levels
in the blood may one day be used as a prognostic factor.
And breast cancer patients with low tumor levels of the enzyme that breaks down
27-HC did not live as long as women who can detoxify it better.
The bottom line is that some estrogen- driven breast tumors may rely
on 27-HC to grow when estrogen isn't available.
And that may explain a second breast cancer mystery.
Over 80% of breast cancers start out responding to estrogen,
and so what we do is use hormone blockers,
either aromatase inhibitors to stop the formation of estrogen in the first place,
or tamoxifen to block its action.
Despite the efficacy of these drugs, many patients relapse with resistant tumors.
And that's where oxidized cholesterol can come in.
27-HC can fuel breast cancer growth without estrogen,
which could explain why sometimes these estrogen blockers don't work.
And finally, 27-HC may explain why breast cancer patients
with higher vitamin D levels appear to live longer.
Vitamin D supplementation decreases 27-HC levels in the blood.
The best way, though, may be to just lower overall cholesterol.
Lower cholesterol, and you lower oxidized cholesterol.
So discovering this role of cholesterol is actually really good news,
since cholesterol is a highly amenable risk factor,
either by lifestyle, dietary, or pharmacologic interventions.
The implications of these findings, according to the principal investigator,
is that lowering cholesterol with dietary changes or drugs
could reduce a women's breast cancer risk or slow tumor growth.
Finally, when it comes to uterine fibroids,
is soy helpful, harmful, or harmless?
About 1 in 4 women will eventually suffer from fibroids,
most commonly manifesting as excessively
heavy periods and pain or pressure.
Why might you feel pressure?
Because you may be carrying around 26 pounds
of tumors in your uterus.
Fibroids are the most common reason women get hysterectomies—
having their uterus removed completely,
a major surgery associated with disability and death,
but all surgery carries risk.
The chances of dying within a month of surgery
may only be about 1 in 1200,
which makes it among our safest surgeries,
safer than getting your gallbladder removed, for example.
But, of course, you lose the ability to bear children,
and costs billions of dollars a year.
Yet, despite the high prevalence,
significant pain and suffering, and huge economic impact,
relatively little is understood about the cause
and disease process that lead to fibroid tumors.
Avoiding atomic bomb blasts whenever you can
is probably a good idea in terms of decreasing fibroids risk,
but what about more easily modifiable risk factors?
Well, alcohol consumption is associated
with increased risk, particularly beer,
and whenever you hear that, whenever you hear beer specifically,
you think of the hormonal effects specific to beer,
specifically the powerful phytoestrogen found in hops.
Well, if that phytoestrogen is increasing fibroids risk,
what about the phytoestrogens in soy?
Well, this was looked at in the Black Women’s Health Study.
Fibroids are 2 to 3 times more prevalent
among African-American women;
so, they thought maybe dairy intake
might be contributing to the disparity,
given their higher levels of lactose intolerance.
And indeed, dairy consumption
was associated with reduced risk.
They figured it was the calcium content
or maybe the vitamin D,
but perhaps the women were drinking soy milk
instead and that was increasing their risk?
No, soy intake was found to be unrelated,
same finding in a group of predominantly white women,
though they did note a protective association
with the amount of lignans flowing through their bodies.
Lignans are another class of phytoestrogens
found predominantly in flaxseeds,
but throughout the plant kingdom.
Hard to make any generalizations
about soy phytoestrogens, though,
as soy consumption was rather low across the board.
This was done in Washington state.
If you go to Japan,
where they have the highest per capita
soy consumption in the world,
you could get a bigger spread of intakes.
The researchers had previously found
that soy intake was inversely associated
with the risk of hysterectomy,
meaning women who ate more soy
had lower hysterectomy rates,
suggesting a potentially protective effect
of soy against uterine fibroids,
since that’s the main reason
women have their uterus removed.
This would be consistent with in vitro studies
that found that the main soy phytoestrogen
seemed to inhibit fibroid tissue proliferation in a petri dish.
But, when they specifically looked,
there was no evidence of a link to soy at all,
protective or otherwise.
The same was found in one study out of China.
Fruit and vegetable intake was associated with
significantly lower risk of fibroids,
but soy food consumption was not.
But a second study out of China, published the same year,
found a significant association
between soymilk intake and fibroids.
That’s consistent with the three alarming case reports
of women with symptomatic fibroids
reporting an “unusually” high intake of soymilk,
or regularly consuming “excessive” amounts of soy,
or “extremely high” intakes of soy
every day for decades.
It's hard to take these cases seriously
when nowhere do they actually say
how much they were consuming.
The only quantitative mention was 40 grams of isoflavones,
which roughly translates to 400 gallons
of soymilk every day—
that would be excessive, but also impossible.
The only way to know for sure is to put it to the test.
Not just a population study or anecdotal reports
but randomize women to two years of soy phytoestrogens—
the amount found in 3 to 5 cups of soymilk a day—
and no significant effect
on the frequency or growth of fibroids was found.
We would love it if you could share with us your stories
about reinventing your health through evidence-based nutrition.
Go to nutritionfacts.org/testimonials.
We may share it on our social media to help inspire others.
To see any graphs, charts, graphics, images, or studies mentioned here,
please go to the Nutrition Facts Podcast landing page.
There you’ll find all the detailed information you need –
plus, links to all of the sources we cite for each of these topics.
My last two books are “How to Survive a Pandemic”
and the “How Not to Diet Cookbook”.
Stay tuned for December 5, 2023
for the launch of my new one, How Not to Age.
And, of course, all the proceeds I receive from the sales
of all my books goes directly to charity.
NutritionFacts.org is a nonprofit, science-based public service,
where you can sign up for free daily updates
on the latest in nutrition research via bite-sized videos and articles.
Everything on the website is free.
There’s no ads, no corporate sponsorship,
no kickbacks.
It’s strictly non-commercial. I’m not selling anything.
I just put it up as a public service, as a labor of love,
as a tribute to my grandmother,
whose own life was saved with evidence-based nutrition.