"Flaxseed vs. Prostate Cancer" Why is there such a huge disparity
in prostate cancer rates? The incidence of clinically malignant
prostate cancer is highest in African-Americans—
some 30-fold greater than in Japanese men,
and 120 times greater than seen in Chinese
men in Shanghai. Well, in general, the Western diet is
one in which animal protein and fat consumption is high,
whereas the fiber intake is low. In contrast, the proportion of the
total caloric intake from animal fat in the more vegetarian-style
Oriental diet is low, and the fiber content is higher. So, maybe diet is playing a role
in some of these diseases. But, these healthier diets are not
just low in animal proteins and fat, and high in starch and fiber— they are also rich in
weak plant estrogens.
This study, for example,
found higher levels of phytoestrogens in the prostate fluids of men
in countries with relatively low rates of
prostate cancer. In vitro studies have shown lignans can
slow the growth of prostate cancer cells in a petri dish. So, a pilot study was launched on
flaxseed supplementation in men, with prostate cancer,
before surgery. Why flaxseeds? Because, while these anti-cancer
lignans are found throughout the plant kingdom, flaxseeds have up
to 800 times more than any other food. So, they took a bunch
of men with prostate cancer, about a month before they
were scheduled for surgery to get their prostates removed,
and started them on a relatively low-fat diet, with three tablespoons
of ground flaxseed, to see what effect that might have
on the growth of their tumors. And, though they were skeptical that
they would observe any difference in tumor biology in the
diet-treated patients with such a short-term
dietary intervention, just within those few weeks,
they found significantly lower cancer proliferation rates,
and significantly higher rates of cancer cell death.
Now, this was compared to
so-called historical controls, meaning compared to
the kind of cancer growth one typically sees
in their situation— not to an actual,
randomized, control group. But, a few years later,
a study was finally published in which men could act
as their own controls. These were men that just
got their prostates biopsied, and were scheduled to get a
repeat biopsy in six months’ time. So, they did the same thing. After the first biopsy,
they reduced the fat in their diet, and put them on ground flaxseeds
to see if it made their repeat biopsy look any different. These were men with
what’s called PIN, which is like the prostate equivalent
of ductal carcinoma in situ in the breast—
an early stage of cancer. That’s why they were
getting repeat biopsies, to make sure it
wasn’t spreading.
And, this is what they found. Significant drop in PSA levels (which is a biomarker
of prostate cell growth); a drop in cholesterol (which is what we’d expect with a
lower-fat diet, and all that extra fiber); and, importantly, a significant decrease
in the cellular proliferation rate. In fact, in two of the men,
their PSA levels dropped so much, they didn’t even have to go through
with the second biopsy at all.
There hasn’t been
much research on this kind of precancerous
prostatic hyperplasia, with only four epidemiological
studies reported at the time. They yielded varying findings,
with increased risk associated with higher energy, protein,
and animal product intake, and decreased risk related to
the consumption of alcohol, fruit, and green and yellow vegetables— in sum, a low-fat, plant-based diet,
high in phytoestrogens..
