June 30, 2007
Diet Factors Against Prostate Cancer

Here's a tour through a large assortment of studies on dietary and lifestyle factors that influence prostate cancer risks. Men who are willing to implement most of the recommendations here would greatly decrease their odds of getting prostate cancer. Note that many of the changes (e.g. less omega 6 fatty acids, more omega 3 fatty acids, less meat, more vegetables, more fruit, more vitamin D) would reduce the risks of other forms of cancer as well. Daily ground flaxseed made diagnosed prostate cancer cells less vigorous.

The researchers will present their results on Saturday, June 2, during a news briefing at the annual meeting of the American Society of Clinical Oncology, in Chicago. The multisite study, which was funded by the National Institutes of Health, also involved researchers at the University of Michigan and the University of North Carolina at Chapel Hill.

In the study, the researchers examined the effects of flaxseed supplementation on men who were scheduled to undergo prostatectomy -- surgery for the treatment of prostate cancer. The men took 30 grams of flaxseed daily for an average of 30 days prior to surgery. Once the men's tumors were removed, the researchers looked at tumor cells under a microscope, and were able to determine how quickly the cancer cells had multiplied.

Men taking flaxseed, either alone or in conjunction with a low-fat diet, were compared to men assigned to just a low-fat diet, as well as to men in a control group, who did not alter or supplement their daily diet. Men in both of the flaxseed groups had the slowest rate of tumor growth, Demark-Wahnefried said. Each group was made up of about 40 participants.

Study participants took the flaxseed in a ground form because flaxseed in its whole form has an undigestible seed coat, she said. Participants elected to mix it in drinks or sprinkle it on food, such as yogurt.

You'd probably need to get a seed grinder to make the ground seed once or twice a week. Though maybe freezing would let you make it less often.

Cut back on the omega 6 fatty acids found in vegetable oils and meats and eat more omega 3 fatty acids from fish.

Nutritionists recommend that people consume equal proportions of omega-3 and omega-6 PUFA. However, in current western diets, the proportion of omega-6 to omega-3 is between 30 and 50 to one.

The mice were fed either a diet high in omega-3 (ratio of omega-6 to omega-3 was 1:1) a diet low in omega 3 (ratio omega-6 to omega-3 was 20:1), or a diet high in omega-6 (ratio of omega-6 to omega-3 was 40:1). The scientists compared survival rates and weighed the animals’ prostates to measure tumor progression.

Mice with the tumor suppressor gene remained free of tumors and had 100 percent survival, regardless of diet. In mice with the gene defect, survival was 60 percent in animals on the high omega-3 diet, 10 percent in those on the low omega-3 diet and 0 percent in those on the high omega-6 diet.

“This suggests that if you have good genes, it may not matter too much what you eat,” said Chen, a professor of cancer biology. “But if you have a gene that makes you susceptible to prostate cancer, your diet can tip the balance. Our data demonstrate the importance of gene-diet interactions, and that genetic cancer risk can be modified favorable by omega-3 PUFA.”

Pomegranate slows prostate cancer in mice.

The research team then progressed to tests in mice that had been injected with prostate cancer cells from humans and developed malignancies. The 24 mice were randomly divided into three groups. The control group received normal drinking water, while the animals in the second and third groups had their drinking water supplemented with .1 percent and .2 percent pomegranate extract respectively. The doses for the mice were chosen to parallel how much pomegranate juice a typical healthy human might be willing to eat or drink daily.

The results were dramatic: the mice receiving the higher concentration of pomegranate extract showed significant slowing of their cancer progression and a decrease in the levels of prostate-specific antigen (PSA), a marker used to indicate the presence of prostate cancer in humans. The animals that received only water had tumors that grew much faster than those in the animals treated with pomegranate extract.

Pomegranate juice also slows prostate cancer growth in men.

Drinking an eight ounce glass of pomegranate juice daily increased by nearly four times the period during which PSA levels in men treated for prostate cancer remained stable, a three-year UCLA study has found.

The study involved 50 men who had undergone surgery or radiation but quickly experienced increases in prostate-specific antigen or PSA, a biomarker that indicates the presence of cancer. UCLA researchers measured "doubling time," how long it takes for PSA levels to double, a signal that the cancer is progressing, said Dr. Allan Pantuck, an associate professor of urology, a Jonsson Cancer Center researcher and lead author of the study.

Inositol hexaphosphate found in high fiber foods reduces prostate cancer tumor size.

Compound found in high-fiber foods shows promise against prostate cancer — A dietary component found in most whole grain foods, beans, nuts and other high-fiber items shows promise in animal studies as a potent weapon for preventing prostate cancer. The compound, inositol hexaphosphate (IP6), was fed to animal models of prostate cancer and resulted in up to a 66 percent reduction in tumor size in comparison to control animals that were given water instead, the researchers say.

Turmeric and cauliflower against prostate cancer.

Rutgers researchers have found that the curry spice turmeric holds real potential for the treatment and prevention of prostate cancer, particularly when combined with certain vegetables.

The scientists tested turmeric, also known as curcumin, along with phenethyl isothiocyanate (PEITC), a naturally occurring substance particularly abundant in a group of vegetables that includes watercress, cabbage, winter cress, broccoli, Brussels sprouts, kale, cauliflower, kohlrabi and turnips. "The bottom line is that PEITC and curcumin, alone or in combination, demonstrate significant cancer-preventive qualities in laboratory mice, and the combination of PEITC and curcumin could be effective in treating established prostate cancers," said Ah-Ng Tony Kong, a professor of pharmaceutics at Rutgers, The State University of New Jersey.

A daily glass of red wine reduces prostate cancer risk.

SEATTLE – Drinking a glass of red wine a day may cut a man's risk of prostate cancer in half, and the protective effect appears to be strongest against the most aggressive forms of the disease, according to a new study led by investigators at Fred Hutchinson Cancer Research Center.

Diet and lifestyle changes might be enough to stop or reverse prostate cancer.

The study was directed by Dean Ornish, MD, clinical professor, and Peter Carroll, MD, chair of the Department of Urology, both of the University of California, San Francisco, and the late William Fair, MD, chief of urologic surgery and chair of urologic oncology, Memorial Sloan-Kettering Cancer Center.

The research team studied 93 men with biopsy-proven prostate cancer who had elected not to undergo conventional treatment for reasons unrelated to this study. The participants were randomly divided into either a group who were asked to make comprehensive changes in diet and lifestyle or a comparison group who were not asked to do so.

After one year, the researchers found that PSA levels (a protein marker for prostate cancer) decreased in men in the group who made comprehensive lifestyle changes but increased in the comparison group. There was a direct correlation between the degree of lifestyle change and the changes in PSA. Also, they found that serum from the participants inhibited prostate tumor growth in vitro by 70 percent in the lifestyle-change group but only 9 percent in the comparison group. Again, there was a direct correlation between the degree of lifestyle change and the inhibition of prostate tumor growth.

Participants in the lifestyle-change group were placed on a vegan diet consisting primarily of fruits, vegetables, whole grains, and legumes supplemented with soy, vitamins and minerals. They participated in moderate aerobic exercise, yoga/meditation, and a weekly support group session. A registered dietitian was available for consultation, and a nurse case manager contacted the participants once a week for the first three months and weekly thereafter.

Give up meat and dairy and eat lots of plants.

The study, published in the September issue of Integrative Cancer Therapies, focused on the change in the levels of prostate-specific antigen (PSA), an indicator of the cancer, in response to a plant-based diet and stress reduction. Patients were taught to increase consumption of plant-based foods such as whole grains, cruciferous and leafy green vegetables, beans and legumes, and fruit, and to decrease the intake of meat, dairy products, and refined carbohydrates. They were also provided with stress management training, which incorporated meditation, yoga and Tai Chi exercises. The plant-based diet and stress reduction were effective in significantly reducing the PSA rate, indicating a reduction in the rate of progression of the prostate cancer.

My guess is you'll be much better off if you avoid grains and just eat non-grain plants. I wonder if the stress management techniques contributed to the benefit.

The diet changes were made for men with early stage prostate cancer. But the smarter thing to do is to make the diet changes before you get prostate cancer.

Up to 73% of men with prostate cancer take nonprescription supplements, and smaller numbers use diet, exercise, or both in the hope of improving their outcome. Most of these men also receive conventional therapy, but a few depend on lifestyle alone. The appeal of lifestyle therapy is obvious—but does it work? Experts don’t know, though research raises hope that it may have a beneficial impact, reports the July 2007 issue of Harvard Men’s Health Watch.

All of the 93 men who signed up for the trial had newly diagnosed low- to moderate-grade cancers that were localized to the prostate gland. Half were randomly assigned to a lifestyle program, and half got no advice on lifestyle changes. The program that researchers created included four elements: An ultra-low-fat vegan diet; supplements, including soy, fish oil, vitamins E and C, and selenium; an exercise program of walking 30 minutes six days a week; and stress reduction that included yoga-based stretching, breathing, and meditation for an hour a day.

At the end of a year, a small but significant difference was evident. The average PSA in the intensive lifestyle group fell, whereas the average PSA in the untreated men rose. The participants in the lifestyle group also showed favorable cancer-fighting changes in their blood.

Keep your weight under control.

“I was very surprised by the findings,” said Kristal, member and associate head of the Cancer Prevention Program in the Hutchinson Center’s Public Health Sciences Division. “We found the prostate-cancer-specific mortality risk associated with obesity was similar regardless of treatment, disease grade or disease stage at the time of diagnosis,” he said. “If a man is obese at the time of diagnosis, he faces a 2.6-fold greater risk of dying as compared to a normal-weight man with the same diagnostic profile, regardless of whether he has a radical prostatectomy or radiation therapy, whether or not he gets androgen-deprivation therapy, whether he has low- or high-grade disease and whether he has localized, regional or distant disease,” Kristal said, referring to the degree of cancer spread.

The researchers also found that obese men diagnosed with local or regional disease – that is, disease that is confined to the prostate or has spread to into surrounding tissue – face a 3.6-fold increased risk of cancer spreading into distant organs, or metastasis, as compared to prostate-cancer patients of normal weight.

The message that soy reduces prostate cancer risk is perhaps an oversimplification.

PHILADELPHIA – The largest study examining the relationship between the traditional soy-rich Japanese diet and development of prostate cancer in Japanese men has come to a seemingly contradictory conclusion: intake of isoflavone chemicals, derived largely from soy foods, decreased the risk of localized prostate cancer but increased the risk of advanced prostate cancer.

The prospective study of 43,509 men, published in the March issue of Cancer Epidemiology, Biomarkers & Prevention, suggests that the effects of isoflavones on prostate cancer development may differ according to disease stage, say researchers at the National Cancer Center in Japan.

One possible explanation is that isoflavones may delay the progression of latent prostate cancer only; once tumors lose estrogen-receptor beta expression and become aggressive, isoflavones may fail to protect against the development of advanced cancer, and might even increase the risk of progression, possibly by reducing serum testosterone, researchers say. It is also possible that advanced and localized prostate cancer may be different tumor subtypes, which may react differently to isoflavones.

The message that lycopene in tomatoes reduces prostate cancer risk might not be true.

PHILADELPHIA -- Tomatoes might be nutritious and tasty, but don’t count on them to prevent prostate cancer. In the May issue of Cancer Epidemiology, Biomarkers & Prevention, researchers based at the National Cancer Institute and Fred Hutchinson Cancer Research Center report that lycopene, an antioxidant predominately found in tomatoes, does not effectively prevent prostate cancer. In fact, the researchers noted an association between beta-carotene, an antioxidant related to lycopene, and an increased risk for aggressive prostate cancer.

According to the researchers, the study is one of the largest to evaluate the role of blood concentrations of lycopene and other carotenoid antioxidants in preventing prostate cancer. Study data were derived from over 28,000 men enrolled in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, an ongoing, randomized National Cancer Institute trial to evaluate cancer screening methods and to investigate early markers of cancer.

Whether multivitamins provide a cancer risk reduction benefit is far from clear.

Karla Lawson, Ph.D., of the National Cancer Institute in Bethesda, Md., and colleagues followed 295,344 men enrolled in the National Institutes of Health-AARP Diet and Health Study to determine the association between multivitamin use and prostate cancer risk. After five years of follow-up, 10,241 men were diagnosed with prostate cancer, including 8,765 with localized cancers and 1,476 with advanced cancers.

The researchers found no association between multivitamin use and the risk of localized prostate cancer. But they did find an increased risk of advanced and fatal prostate cancer among men who used multivitamins more than seven times a week, compared with men who did not use multivitamins. The association was strongest in men with a family history of prostate cancer and men who also took selenium, beta-carotene, or zinc supplements.

As long term readers know by now, the cancer risk reduction benefit from vitamin D is much clearer than that from other vitamins. See the posts 60% Cancer Drop From Vitamin D Supplements and Vitamin D Could Decrease Overall Cancer Risk 30%.

The younger among you may be thinking that by the time you reach the high cancer risk years we'll have effective cures for cancer. A person in their 20s isn't going to die from cancer they get in the year 2047. But keep in mind that cancer is a consequence of accumulated cell damage. We'll have cures for cancer before we get full body rejuvenation therapies. A diet that reduces your risk of cancer will slow your body aging and therefore if you eat a cancer risk reduction diet you won't grow as old while waiting for the rejuvenation therapies.

Share |      Randall Parker, 2007 June 30 09:25 AM  Aging Diet Cancer Studies

Mthson said at June 30, 2007 2:51 PM:

Pomegranate juice is seeing a major rise in popularity in the US in the last couple years.

That article also claims "Unlike most fruit juices, drinking a commercial juice such as POM Wonderful is more healthful than eating the fruit itself, because 70 percent of the antioxidants found in the juice are released from the peel when the pomegranate is squeezed."

TTT said at June 30, 2007 4:02 PM:


Can you do a grand, unified post that summarizes a full, recommended dietary plan?

You had an article some time ago that spoke of the benefits of broccoli and tomatoes. Some changes, like stopping red meat, are easy. But additionally stopping dairy and grains are just too big of a sacrifice.

Can you synthesize all the many recommendations from your articles and research into a consolidated dietary plan (with links to all your previous supporting articles as appropriate)? You can update the dietary plan as more articles come forth.

Only then will all the good research you are doing be simplified down enough for everyone to benefit.

Randall Parker said at June 30, 2007 5:11 PM:


I suspect the bigger problem isn't knowing the right things to eat but rather to find ways to stop eating the foods you ought to avoid. If you can't stop eating grains then at least eat whole grains. Also, try to eat vegetables first in a meal. The scientific results about specific foods are less important than general rules like more fruits and vegetables and less meats and dairy.

I've been trying to figure out how to improve my own diet based on all the reports I read. Remember that report of a few weeks ago about how foods that have lower calorie density are the easiest to control your weight with? Those foods tend also to be vegetables and other foods that have high health ratings (nuts being an exception of high health benefit but high calories per unit weight). If you shift toward foods with low calories per lb you will tend to shift toward an ideal diet.

Start doing calculations on the foods you eat for calories per lb.

Some examples of foods in calories per lb:

Zucchini squash: 73
Turnips: 95
Green cabbage: 109
Apple sauce: 252
Andersen's Split Pea Soup: 277
Parsnips: 410
Potato Baked, whole: 422
Potatoes, sweet: 454
Yams: 527
Small red beans: 756
Salmon: 792
Whole wheat bread: 1122
Bread, Italian: 1235
Total cereal: 1513
Uncle Ben's Converted Rice: 1575
Flaxseed: 2234
Soybean butter: 2411
Peanut butter: 2837
Brazil nuts: 2875

On calorie density veggies and fruits are better than potatoes that are better than beans that are better than grains.

I'm using a low cal mayo with cabbage and use 300 calories of mayo (6 tablespoons) to eat a whole head of cabbage that is about 300 calories.

TTT said at June 30, 2007 6:08 PM:


But what about micronutrients that block certain diseases? I have read your articles that have mentioned tomotoes, broccoli, pomogranate juice, salmon, etc.

It is not so much calories that are my concern, but rather the need to get as many disease-reducing micronutrients as possible. Maybe you can make a list of all the foods you have written about, and which particular diseases they reduce the risk of.

At any rate, I am just trying to get a condensed summary of all of your findings, in the form of a realistic list that a person can use to shape a diet.

Randall Parker said at June 30, 2007 6:31 PM:


The fewer calories you get from grains, meat, and dairy the more of the beneficial foods you can eat.

Keep in mind that in studies I've come across on fruit and vegetable consumption there is not a number of servings per day at which the marginal benefits go to 0. If you can eat 10 servings of fruits and vegetables per day then you can get more benefits than if you eat 9 per day. This is why you should eat less meat, dairy, and grains: to make room for the really beneficial stuff.

As for particular beneficial compounds in particular foods: If you are at risk for particular diseases then eating for those compounds makes sense. But generally what you need to do is to eat lots of fruits and vegetables and perhaps some nuts and definitely some omega 3 fatty acids source.

Within the fruits and vegetables there are certainly better ones. The berries seem more beneficial than the bigger fruits since they have more bioflavonoids per unit weight. But most people simply need to eat more fruits and vegetables without getting into the details.

As for what I've written previously: I have it nicely organized into category archives. Look at the Aging Diet archives. I have Aging Diet Cancer Studies, Aging Diet Studies, and other variations. See the right hand column of my front page for links to the category archives.

ron b said at July 1, 2007 7:26 AM:

Re: flaxseed - Whole Foods sells a few varieties of ground flaxseed. Conventional and organic and, my favorite, 'golden' flaxseed. Which is tasteee. Keep it in the fridge or even the freezer, eat it like a breakfast cereal.

Hopefully Anonymous said at July 1, 2007 2:25 PM:

I second TTT's request.

Mthson said at July 1, 2007 4:41 PM:

Flax seeds can just be put in a blender and poured over cereal or other food items. Tastes great.

Jim Rose said at July 2, 2007 6:44 AM:

Re:Vitamin D and prostate cancer

The double blinded, placebo controlled study showing that vitamin D reduces the cancer rate by almost a factor of four is the most important public health finding of the last fift years -- if it holds up. I am recommending that everyone in my extended family take at least 1000 IU of vitamin D and 1000 mg of calcium daily. The low key (non-existent) reaction in the media is very surprising to me. If this had been a new patented drug we would rightfully never hear the end of it.

I guess that a large scale controlled test of this result would take 10,000 people and 5-7 years.
What should be done for the public health in the meantime?

James Campbell said at June 13, 2008 11:07 AM:

Everything I have researched about Goji berries and health claims have been positive. Yet, little is stated regarding how they fit into the "equation" as regards their supposed health benefits and prostate health and PSA levels, even though their use has not be approved by the FDA.

James Campbell said at June 13, 2008 11:16 AM:

Everything I have researched about Goji berries and health claims have been positive. Yet, little is stated regarding how they fit into the "equation" as regards their supposed health benefits and prostate health and PSA levels, even though their use has not be approved by the FDA. Can anyone enlighten me regarding this issue? Thanks

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