What happens when men with prostate cancer and prostatic intraepithelial neoplasia (PIN) are placed on a relatively low-fat diet supplemented with ground flaxseeds?
Images thanks to National Cancer Institute via Wikimedia Commons
Why is there such a huge disparity in prostate cancer rates? The incidence of the 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 terms 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, of which there are two types. We hear a lot about the soy isoflavones, but less about the other group lignans. This study found higher levels of lignans in the prostate fluids of men in countries with relatively low rates of prostate cancer and in vitro studies showed lignans can slow the growth of prostate cancer cells in a petri dish,so a pilot study was performed on flaxseed supplementation in men with prostate cancer before surgery. Why flaxseeds? Because while lignans are found throughout the plant kingdom, flax 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 a day of ground flax seed to see what effect that 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, they found significantly lower cancer proliferation rates and significantly higher rates of cancer cell death. That was compared to so-called historical controls, meaning compared to what the kind of growth one typically sees in their situation, not to actual randomized control group, but a few years later a study was published in which men were their own controls. These were men who just got their prostates biopsied and were scheduled to get repeat biopsies in six months. 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, precancerous changes. 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 one would expect with a lower fat diet and all that extra fiber, and the most important, 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. There hasn't been much research on this kind of prostatic hyperplasia, with only four epidemiologic 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.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson.
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Slowing the Growth of Cancer is good, but how about Cancer Reversal Through Diet? In other words, if one plant could do that, what about a whole diet chocked full of plants? See my video series that goes from Ex Vivo Cancer Proliferation Bioassay (actually Engineering a Cure) to The Answer to the Pritikin Puzzle. And for benign prostate gland enlargement Prostate vs. Plants, and Prostate vs. a Plant-Based Diet (with background in Some Prostates Are Larger than Others).
What about for breast cancer? See Breast Cancer Survival and Lignan Intake. More on these wonderful seeds in Flax and Fecal Flora, my smoothies (A Better Breakfast), and the oldie but goodie Just the Flax, Ma’am. What about chia? Find out which is better in Flaxseeds vs. Chia Seeds.
Since the dietary intervention involved both reducing fat intake and flaxseed consumption, how do we know the flax had anything to do with it? That's the subject of the next video Was It the Flaxseed, Fat Restriction, or both?
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