Friday Facts: Diet and Prostate Cancer

812rexUR0rLSo, this is another long-ish excerpt from Dr. Michael Greger’s excellent book: “How Not To Die“. He makes a big point in his book about giving all the content on his website, nutritionfacts.org, out for free so I hope he will not mind that I am including these long excerpts.

I was inspired to post this because a friend of a friend was just diagnosed with prostate cancer. I found this out over lunch, and it was a very strange moment for me because at this lunch my friends were all eating double cheeseburgers with fries, while I was eating veggie soup , tabbouleh salad, hummus, and vegetarian dolmeh. As we continued to eat lunch, I just kept thinking to myself that with every bite they were increasing their risk of cancer, and I was decreasing mine.  It made me feel even more committed to this change in my life, and gave me the courage to send the excerpt below to my friends at that lunch in hopes it will inspire them.

The excerpt:

Prostate Cancer Reversal Through Diet?

If a healthy diet can turn your bloodstream into a cancer-fighting machine, what about using it not just to prevent cancer but also to treat it? Other leading killers, including heart disease, type 2 diabetes, and hypertension, can be prevented, arrested, and even reversed, so why not cancer?

To test this question, Dr. Ornish and his colleagues recruited ninety-three men with prostate cancer who had chosen not to undergo any conventional treatment. Prostate cancer can be so slow growing and the side effects of treatment so onerous that men diagnosed with it often choose to be placed in a medical holding pattern called “watchful waiting” or “expectant management.” Because the next step is often chemotherapy, radiation, and/ or radical surgery that may leave men incontinent and impotent, doctors try to delay treatment as long as possible. And since these patients aren’t actively doing anything to treat the disease, they represent an ideal population in whom to investigate the power of diet and lifestyle interventions.

The prostate cancer patients were randomized into two groups: a control group that wasn’t given any diet or lifestyle advice beyond whatever their personal doctors told them to do, and a healthy-living group prescribed a strict plant-based diet centered around fruits, vegetables, whole grains, and beans, along with other healthy lifestyle changes, such as walking for thirty minutes, six days a week.

Cancer progression was tracked using PSA levels, a marker of prostate cancer growth inside the body. After a year, the control group’s PSA levels increased by 6 percent. That’s what cancer tends to do: grow over time. But among the healthy-living group, PSA levels decreased by 4 percent, suggesting an average shrinkage of their tumors. No surgery, no chemotherapy, no radiation— just eating and living healthfully.

Biopsies taken before and after the diet and lifestyle intervention showed that the expression of more than five hundred genes was affected. This was one of the first demonstrations that changing what you eat and how you live can affect you at a genetic level, in terms of which genes are switched on and off. Within a year after the study ended, the cancers in the patients in the control group grew so much that 10 percent of them were forced to undergo a radical prostatectomy, a surgery that involves the removal of the entire prostate gland and surroundingtissues. This treatment can lead not only to urinary incontinence (urine leakage) and impotence but to alterations in orgasmic function in approximately 80 percent of men undergoing the procedure. In contrast, none in the plant-based diet and lifestyle group ended up on the operating table.

How were the researchers able to convince a group of older men to basically eat a vegan diet for a year? They evidently delivered prepared meals to their homes. I guess the researchers figured men are so lazy they’ll just eat whatever is put in front of them— and it worked!

Now, how about in the real world? Realizing that doctors apparently can’t get most men with cancer to eat even a measly five servings of fruits and veggies daily, a group of researchers at the University of Massachusetts settled on just trying to change their A:V ratio, or the ratio of animal to vegetable proteins in their diets. Maybe just a reduction in meat and dairy and an increase in plant foods would be enough to put cancer into remission?

To test this, the researchers randomized prostate cancer patients into two groups, one group that attended classes on eating a more plant-based diet and a conventional-care group that received no dietary instruction. The healthy-eating advice group was able to drop their A:V ratio down to about 1: 1, getting half their protein from plant sources. In contrast, the control group’sratio stayed up around 3: 1 animal-to-plant protein.

Those on the half-vegan diet did appear to slow down the growth of their cancer. Their average PSA doubling time— an estimate of how fast their tumors may have been doubling in size— slowed from twenty-one months to fifty-eight months. In other words, the cancer kept growing, but even a part-time plant-based diet appeared to be able to significantly slow down their tumors’ expansion. It is worth noting, though, that Dr. Ornish and colleagues were able to demonstrate that a full-time plant-based diet allowed for an apparent reversal in cancer growth: The subjects’ PSA levels didn’t just rise more slowly, but they trended downward. Thus, the ideal animal-to-plant protein ratio may be closer to zero to one.

The Worst A and the Best V

What if there’s just no way Grandpa’s going vegan, leaving you with only half measures? What would be on the short list of foods for him to avoid, or to include, in his diet?

Based on the Harvard University prostate cancer progression and mortality data detailed above, eggs and poultry may be the worst offenders: Patients may face twice the cancer progression risk from eating less than a single egg per day and up to quadruple the risk fromeating less than a single serving of chicken or turkey daily.

On the other hand, if you were to add only one thing to your diet, consider cruciferous vegetables. Less than a single serving a day of broccoli, brussels sprouts, cabbage, cauliflower, or kale may cut the risk of cancer progression by more than half.

Watching your animal-to-plant protein ratio might be useful for cancer prevention in general. For example, the largest study ever performed on diet and bladder cancer— comprising nearly five hundred thousand people— found that an increase in animal protein consumption of just 3 percent was associated with a 15 percent increased risk of bladder cancer. On the other hand, an increase in plant protein intake of only 2 percent was associated with a 23 percent decreased cancer risk.

Greger MD, Michael; Stone, Gene. How Not to Die: Discover the Foods Scientifically Proven to Prevent and Reverse Disease. Flatiron Books. Kindle Edition.

I strongly encourage you to buy and read the whole book — it is excellent.
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