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 has 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 3 tablespoons of ground flaxseed

to see what effect it might have on the growth of their tumors.

Though they were skeptical that they would observe any differences 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 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 the 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,

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 drop 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 pre-cancerous 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.