"Which Seaweed for Breast Cancer?"
Unfortunately, as the traditional diets of East Asia westernize,
their breast cancer rates have risen,
which some have linked
to a quadrupling of animal product consumption.
This is the breast cancer rate of Japanese women in Japan.
If the emigrate to the United States,
within 10 years they're up to here,
and if they hang around long enough,
here's the risk of resident Japanese Americans
living in the United States.
Note, though, that it's still somewhat lower
than the U.S. national average.
This may be because some of the dietary habits
may carry with them such as soy consumption,
green tea, maybe eating more mushrooms,
but maybe partly it's the seaweed.
We've known for over a decade that in vitro,
in a petri dish, seaweed broth is effective
at clearing cancer cells.
Here's three different types of human breast cancer,
measuring cancer cell death.
Here's what a widely used chemotherapy drug can do,
and here's seaweed.
Worked even better and, unlike the chemo,
didn't harm normal, noncancerous breast cells.
But what about outside of the test tube, in people?
Well, a population study comparing
women with breast cancer to women without,
found that consuming a single sheet of nori a day,
may cut a woman's odds of breast cancer in half.
We think it's because seaweed favorably alters
estrogen metabolism likely due to a modulation
of the woman's gut bacteria.
It appears the more seaweed you eat,
the less estrogen you have in your system,
which may lower breast cancer risk.
This may be because of all the fiber in sea vegetables,
or it may block the enzyme that undermines
our body's attempt to flush out excess hormones,
or even somehow interfere with estrogen binding to estrogen receptors.
Either way, to effectively lower one's estrogen levels,
Asian women may be able to get away with
maybe one sheet of nori a day,
but American women are so much bigger,
it may take closer to two.
There's lots of yummy seaweed snacks out there
to make it a tasty experience—
just try to get some low-fat, low-sodium ones.
"Walk-ka-may," the seaweed used fresh in seaweed salads
unfortunately did not appear to reduce breast cancer risk,
though it has been found to rather dramatically
lower blood pressure in hypertensives.
Just two teaspoons of seaweed salad a day for a month
dropped their blood pressure 14 points
and after two months was associated
with up to a 2-inch skinner waistline.
As I've mentioned before, though,
I'd recommend avoiding hijike,
which tends to have too much arsenic,
and kelp, which tends to have too much iodine.
In fact, too much seaweed of any type
may actually increase one's risk of thyroid cancer
because of the amount of iodine you'd be taking in,
but there does not appear to be increased risk
at the levels of consumption I'm talking about,
like a sheet of nori a day.
And a study of seaweed eaters in California
actually found decreased risk,
but again we're talking modest levels of intake.
You know, I've frequently talked about the benefits
of dietary diversity, eating different families of fruits and vegetables,
eating different parts of individual plants like beets and beet greens.
If we just stick to land plants, though,
we're missing out on all the plants
from the other 70% of planet earth.
Sea vegetables have phytonutrients found nowhere else,
types of fiber and unique carotenoids,
and polysaccharaides, and various polyphenol defense compounds,
each of which may have anti-cancer properties.
So, I encourage everyone to try experimenting
with sea vegetables until you find one you like,
even if that just means sprinkling some
powdered dulse on your food.