Prostate cancer is the most common cancer among American men and, behind lung cancer, is the #2 cause of cancer death among men. Though the risk for prostate cancer and other prostate problems is strongly related to genetics, other controllable lifestyle factors seem to be even more important. Factors associated with a higher risk for prostate disease and cancer include:
High blood pressure (hypertension)
Diabetes (Type 2 or adult-onset diabetes)
High insulin levels in the blood
Low levels of high-density lipoproteins (HDLs)
Having a "spare tire" or "beer belly"
Sedentary lifestyle
Diet high in fat, especially saturated fat
Excessive intake of calcium, especially from dairy sources
Diet high in red meat
History of kidney stones
History of sexually transmitted disease
Exposure to the heavy metal cadmium
Exposure to agricultural chemicals
Allergies
Aging
Like breast cancer, prostate cancer is a "hormone-sensitive" disease. Its development and progress is strongly influenced by the various natural (made by the body) and artificial (from food and environment) hormones in the body. Many lifestyle factors such as diet, physical activity, and stress management address how the body metabolizes these important and influential hormones.
The prostate is a walnut-sized muscular gland that secretes a thin, milky, fluid that lubricates the urethra (duct for urine and ejaculatory fluids) and helps sperm survive after ejaculation. It surrounds the urethra and for this reason, conditions affecting the size or shape of the prostate directly affect urinary and sexual function.
The prostate is sensitive both to "male" hormones (androgens such as testosterone, dihyrdrotestosterone, and androstenedione) and to "female" hormones (prolactin or estrogens such as estradiol and estrone). Though these are called "male" and "female" hormones, they all naturally occur in both men and women. It is their relative balance that results in good health or in discomfort.
The relative balance of these hormones is influenced by aging, dietary intake, detoxification function of the liver and intestines, exercise, smoking, and exposure to hormone-like chemicals from food and the environment.
Prostate cancer is a hormone-sensitive cancer (as is breast cancer) that will probably affect one in six American men. Each year roughly 200,000 American men are diagnosed with it, and over 30,000 die from it. However, because prostate cancer tends to progress slowly, it is not always life-threatening. Many men wait rather than having medical intervention immediately after their diagnosis, or opt for lifestyle changes.
In its early stages, prostate cancer does not usually cause symptoms. When symptoms do occur, they can include any or all of the following:
Needing to urinate frequently, especially at night
Difficulty starting urination or holding back urine
Inability to urinate
Weak or interrupted flow of urine
Painful or burning urination
Difficulty having an erection
Painful ejaculation
Blood in the urine or semen
Frequent pain or stiffness in the lower back, hips, or upper thighs
These symptoms are not specific for prostate cancer. The first four, especially, are also typically seen in cases of prostate enlargement, a benign condition. The other symptoms may also be caused by infections or prostatitis. If you are experiencing any of these symptoms, it is important to see a doctor immediately.
Dietary Causes
There is so much convincing evidence on the role of diet in prostate cancer that Dr. William Fair and his colleagues from the Memorial Sloan Kettering Cancer Center suggest that prostate cancer may be considered a "nutritional disease."
Dietary factors associated with a higher risk for prostate cancer include:
High level of total fat in the diet
High intake of saturated fats (primarily animal fats)
Excessive calcium intake
High milk consumption (milk is a source of calcium, cholesterol, and animal fat, all of which may be risk factors for prostate cancer when excessive)
High intake of red meat (especially grilled, fried, and broiled meats, which contain carcinogens)
Low intake of fruits and vegetables
Low intake of mustard family vegetables, which contain especially protective nutrients
Low intakes of selenium, vitamin E, lycopene, and other dietary antioxidants
Dietary factors associated with a lower risk for prostate cancer include:
High intake of soy foods (tofu, tempeh, texturized vegetable protein or TVP, soy nuts, soy milk, soy cheese, soy dogs, soy burgers, etc.)
High intake of the antioxidants selenium and vitamin E
High intake of whole grains, nuts, and seeds
Vegetarian diet
Adequate intake of vitamin D
Frequent consumption of tomatoes, especially cooked tomatoes in products such as tomato paste and tomato sauce, particularly if the tomato products also contain a little oil
Drinking green tea
A special note for African-American men:
African-American men develop prostate cancer twice as frequently as Caucasian men, and though genetics may play a role, dietary differences between these groups of men are clearly involved. In African-American men, greater consumption of foods high in animal fat is even more strongly linked to prostate cancer than it is for men in general.
One reason for this may be that African-American men, on average, consume 2 to 3 times as much of a particular group of carcinogenic substances (called heterocyclic amines) that are found in fried, broiled, and grilled meats. It is therefore particularly important for African-American men to limit their intakes of these foods.
Nutrient Needs
Soyfoods
Organic soyfoods (such as soymilk, tofu, tempeh, texturized vegetable protein or TVP, soy burgers, and soy dogs) can play an important protective role against prostate cancer. A major study of diet and prostate cancer among men in 42 countries found that soyfoods were the single most significant dietary influence reducing the number of deaths from prostate cancer.
Soyfoods contain "isoflavones," natural substances with weak estrogen-like activity that seem to modulate how the body responds to the estrogens naturally produced by men and women. Consumption of soyfoods is associated with lower rates of numerous hormone-related diseases, including prostate and breast cancer.
Among Japanese men, the lower incidence of prostate disease and lower rate of death from prostate cancer are thought to be related to their lifelong intake of isoflavones, and in American Adventist men, a high intake of soymilk is associated with a 70 percent reduction in prostate cancer risk.
The isoflavones in these simple but remarkable foods show a wide variety of protective effects in laboratory studies, inhibiting the responses of normal prostate cells and of cancer cells to many stimuli that would usually cause them to grow abnormally.
Research published in Cancer Epidemiological Markers supports the substantial protective benefit to be derived from eating soy foods. In this study of 398 Chinese men (133 men with prostate cancer and 265 age and residential community matched controls between the ages of 50 and 89), those consuming the most tofu had a 42% lower risk of developing prostate cancer compared to those consuming the least. When researchers checked the relationship between the soy isoflavones, genistein and daidzen, which are found not only in tofu, but in soy beans and other foods made from them, those consuming the most genistein were found to have a 47% lower risk for prostate cancer, while those consuming the most daidzen had a 44% lower risk.
Further support for isoflavones' protective effects against prostate cancer comes from a study published in Cancer Epidemiological Biomarkers and Prevention (Kurahashi N, Iwasaki M, et al.)
In this 9-year Japanese study involving 43,509 men ranging in age from 45 to 74 years, men eating the most soy food and miso (and therefore consuming more genistein and daidzein, the isoflavones found in soybeans) had a significantly lower risk of localized prostate cancer.
Among the men who were older than 60, the protective effect was strongest. Men whose diets provided the most genistein had a 48% reduced risk of localized prostate cancer compared to men food delivered the least of this isoflavone. Similarly, men consuming the most daidzein and soy foods showed 50% and 48% reduced risks of localized prostate cancer, respectively, compared to men consuming the least daidzein and soy foods.
Additional research has further confirmed isoflavones' prostate-protective effects. (Nagata Y,Sonoda T, et al., J Nutr.)
This case-control study of 200 Japanese men with different stages of prostate cancer-one man in Stage 1, 131 men in Stage 2, 44 men in Stage 3, and 24 men in Stage 4-compared the men's soy isoflavone intake with that of 200 healthy male controls.
Diets that delivered the most isoflavones (89.9 mg/day) from soyfoods-tofu, natto, miso soup, bean curd, soy flour, soy milk, soy sauce, edamame, and soy bean sprouts-were associated with a 58% lower risk of prostate cancer compared to diets providing the least isoflavones (less than 30.5 mg/day).
Practical Tip: All traditional soyfoods are rich sources of isoflavones, providing 30-40 mg per serving. Soy sauce and soy oil, however, contain no isoflavones.
Soyfoods Shown to Stop the Form of Testosterone that Promotes Prostate Cancer
A molecule formed in the intestine when soy is digested can attach to and completely stop DHT, the potent form of testosterone that stimulates prostate cancer, acne and male pattern baldness, suggests an animal study published in the April 2004 issue of Biological Reproduction.
The molecule, named equol, is formed from one of the main isoflavones abundant in soy, the phytoestrogen daidzein. Equol promotes the best of all male worlds as it prevents only the dangerous DHT, but not beneficial testosterone, from binding to the androgen (male hormone) receptor.
According to Kenneth Setchell, the researcher who first identified equol in humans 20 years ago, "These findings are of immense clinical importance because blocking the action of the potent androgen DHT has been one of the holy grails of the pharmaceutical industry as a strategy for treating prostate cancer and other related diseases."
While the pharmaceutical industry has developed drugs that inhibit the enzyme that converts testosterone to DHT, the drugs are costly and have unpleasant side effects. Equol doesn't prevent DHT from being produced, but completely inactivates it, achieving the same goal without affecting normal testosterone metabolism and without negative side effects." Directly binding and inactivating DHT without influencing testosterone gives equol the ability to reduce many of the harmful effects of androgens without affecting the beneficial ones," said Robert J. Handa, senior author of the study.
The researchers demonstrated that in male rats, injections of equol reduced the size of the prostate. The rats' testes were removed to eliminate all DHT production. When investigators injected these rats with equol, nothing happened; when they DHT into the rats, their prostates grew, but when the rats were given equol along with the DHT, no prostate growth occurred-the equol prevented the DHT from stimulating prostate growth.
The researchers think equol's protective action may explain why men in Japan, who typically and regularly eat soy, rarely develop prostate cancer despite the fact that, like men in the Western world, as they age, Japanese men suffer equally from BPH (benign prostatic hyperplasia).
The researchers, hopeful that, because of DHT's importance in both acne and male pattern baldness, equol may offer a means of promoting healthy skin and preventing hair loss, have begun further studies to evaluate equol's potential in the treatment of these and other androgen-influenced conditions.
Soy-rich Diet Lowers PSA, but Not Testosterone
Since the lowest incidence of prostate cancer is found in Asian countries where soyfoods are a dietary staple, and a recent meta-analysis published in the International Journal of Cancer (2005, Vol. 117, pp. 667 - 669) found that men who regularly ate soyfoods had a 30% lower risk of the cancer, researchers in Hawaii decided to put men on a soy-rich diet and evaluate its effects on the prostate cancer marker, PSA.
Soy contains phytonutrients called isoflavones, which exert mild estrogen-like action-a possible concern for men-so researchers also wanted to see if the men's testosterone levels would be affected by a high-soy diet. They weren't.
Led by Gertraud Maskarinec from the Cancer Research Center of Hawaii, the researchers recruited 23 men (ranging in age from 58-65 years) and randomized them to receive either a high soy diet (two servings of soy per day) or a low soy diet (usual diet) for three months. At the end of the first diet period, the men went back to their normal eating habits for one month and then crossed over to eat the other diet for a further three months.
In contrast to the low soy diet, during the high-soy diet, PSA levels dropped 14% with no change in testosterone.
Whether the men would enjoy soyfoods and thus actually eat the soy-rich diet was also a concern. Adherence was assessed by soy calendars, 24-hour dietary recalls, and urine tests measuring isoflavone excretion, which went up on the soy-rich diet. The results were so good that researchers noted," The high adherence as shown by three measures of compliance in this pilot trial demonstrated the feasibility of an intervention based on soy foods among free-living men."
Soy Isoflavones Protectively Alter Men's Estrogen Metabolism
Research suggests that isoflavone phytonutrients found in soybeans may protectively alter men's metabolism of estrogen, lowering men's ratio of 2 hydroxy estrogens to 16 hydroxyestrone (2:16 OH-E1). (Yes, real men produce some estrogen, and in men, the prostate is the primary locus of estrogen production.) Since the 2 hydroxy metabolites of estrogen are less likely to initiate hormone-related cancers than estrogen's 16 hydroxyestrone metabolites, soy's effect of increasing the amount of 2 hydroxy estrogen produced in relation to the amount of 16 hydroxyestrone made in the prostate may help prevent prostate cancer. (Hamilton-Reeves JM, Rebello SA, et al. J Nutr.)
Earlier research linking soy to protection against prostate cancer has suggested that the weak estrogenic activity of soy's isoflavones, which may act to reduce testosterone levels and inhibit 5-alpha-reductase (an enzyme involved in converting testosterone to its most potent form, DHT, which has been linked to prostate growth and male baldness), might also be protective.(Kurahashi N, Iwasaki M, et al., Cancer Epidemiol Biomarkers Prev.)
Practical Tip: Protect your prostate health by making soy foods a staple part of your healthy way of eating. Not a fan of tofu? Soy milk is now an available option, even at most espresso stands. You can take packets of miso to work with you, just as you would any dehydrated soup mix. Miso not only makes a delicious broth on its own, but can be sprinkled like seasoning over brown rice or any grain, any soup, or sautéed vegetable to add great flavor. Try a tofu burger for lunch. Experiment with a few brands till you find one you really enjoy; some (we like BocaBurgers) now do a pretty reasonable job of mimicking the taste and texture of beef. Soy nuts can also go with you to the office for a quick snack.
Avocado Inhibits the Growth of Androgen-Dependent and Androgen-Independent Prostate Cancer Cells
Not only are avocados a rich source of monounsaturated fatty acids including oleic acid, which has recently been shown to offer significant protection against another form of cancer, breast cancer, but these fruits also contain the highest amount of the carotenoid lutein of all commonly eaten fruits, as well as measurable amounts of related carotenoids (zeazxanthin, alpha-carotene and beta-carotene) plus significant quantities of tocopherols (vitamin E).
In a laboratory study published in the January 2005 issue of the Journal of Nutritional Biochemistry, an extract of avocado containing these carotenoids and tocopherols inhibited the growth of both androgen-dependent and androgen-independent prostate cancer cells.
But when researchers tried exposing the prostate cancer cells to lutein alone, the single carotenoid did not prevent cancer cell growth and replication.
Not only was the whole matrix of carotenoids and tocopherols in avocado necessary for its ability to kill prostate cancer cells, but the researchers also noted that the significant amount of monounsaturated fat in avocado plays an important role. Carotenoids are lipid (fat)-soluble, which means fat must be present to ensure that these bioactive carotenoids will be absorbed into the bloodstream. Just as Nature intends, avocado delivers the whole heath-promoting package.
Chili peppers
Red chili peppers' capsaicin, the compound responsible for their pungent heat, stops the spread of prostate cancer cells through a variety of mechanisms, indicates a study published in the March 15, 2006 issue of Cancer Research . Capsaicin triggers suicide in both primary types of prostate cancer cell lines, those whose growth is stimulated by male hormones and those not affected by them. In addition, capsaicin lessens the expression of prostate-specific antigen (PSA), inhibits the ability of the most potent form of testosterone, dihydrotestosterone, to activate PSA, and directly inhibits PSA transcription, causing PSA levels to plummet.
The dose effective for test animals was equivalent to 400 milligrams of capsaicin, three times a week, for a man weighing about 200 pounds. After four weeks of receiving capsaicin, prostate cancer tumor growth and size decreased significantly in the animals.
One warning: Excessive intake of hot chilies has been linked to stomach cancer, so don't go overboard.
Grapefruit's naringenin repairs DNA, may protect against prostate cancer
Naringenin, a flavonoid concentrated in grapefruit, helps repair damaged DNA in human prostate cancer cells (cell line LNCaP), reports a lab study published in the February 2006 issue of the Journal of Nutritional Biochemistry.
The risk of prostate cancer, the most commonly diagnosed cancer in men in the U.S, increases with age since the older we become, the more times our cells have divided and the greater the chance for DNA mutations to occur. DNA repair is one of the body's primary defense mechanisms against the development of cancer since it removes potentially cancer-causing mutations in cells.
Naringenin helps restore health to damaged DNA by inducing two enzymes that repair DNA during the replication stage. These enzymes, 8-oxoguanine-DNA glycosylase 1 (hOGG1), and DNA polymerase beta (DNA poly beta), are both involved in the DNA base excision repair (BER) pathway.
In this study, the researchers measured the repair that occurs when damaged cells are exposed to naringenin by measuring the amounts of two compounds, deoxyguanosine (dG) and 8-hydroxydeoxyguanosine (8-OH-dG). The former is found in normal DNA; the latter, a product of hydroxyl radical attack, is found in damaged DNA. After 24 hours of exposure to 80 micromoles per liter of naringenin, the ratio of 8-OH-dG to dG had decreased by 24%.
The scientists in this study exposed cell cultures to 80 micromoles per liter, an amount we cannot achieve by consuming grapefruit since research indicates that only between 2 and 15% flavonoids in the food we consume are absorbed in the GI tract, and plasma concentrations after eating flavonoid-rich foods range from 0.5 to 1 micromole per liter.
Fortunately, however, the researchers also demonstrated that the concentration of naringenin inside the cells that was needed for its beneficial effects was only 5% of the amount in the medium, and this amount is physiologically achievable in our tissues.
Unlike many other cancers, prostate cancer is slow growing initially and often remains undetectable for a long time. Enjoying grapefruit regularly may be one way to prevent its progression by promoting the repair of damaged DNA in prostate cells, thus preventing them from becoming cancerous.
Cranberries
Enjoy whole cranberries, not just cranberry juice. Cranberry presscake (the material remaining after squeezing juice from the berries), when fed to mice bearing human breast cancer cells, has previously been shown to decrease the growth and metastasis of tumors, and a new study published in the June 2004 issue of the Journal of Nutrition suggests compounds in whole cranberries also inhibit prostate, skin, lung and brain cancer cells as well.
Androgen-dependent prostate cancer cells were inhibited the most (just 10 mg of a warm water extract of cranberry presscake inhibited their growth by 50%). With androgen-independent prostate cancer cells and estrogen-independent breast cancer cells, a larger amount was needed but produced the same beneficial effect (250 mg of cranberry presscake extract inhibited their growth by 50%).
Researchers concluded that the active compounds in whole cranberry prevent cancer by blocking cell cycle progression and inducing cells to undergo apoptosis (programmed cell death).
Green Tea
Green tea polyphenols halt prostate cancer at multiple levels. The polyphenols in green tea help prevent the spread of prostate cancer by mobilizing several molecular pathways that shut down the proliferation and spread of tumor cells, while also inhibiting the growth of blood vessels that supply the cancer with nourishment, according to research published in Cancer Research.
Green tea polyphenols:
decrease insulin-like growth factor-1 (IGF-1), while increasing levels of IGF binding protein-3, which binds IGF-1, further diminishing its activity. (Increased levels of IGF-1 are associated not only with prostate cancer, but cancers of the breast, lung and colon.)
inhibit key cell survival proteins, promoting apoptosis or programmed cell death in cancer cells.
reduce the expression of several compounds (urokinase plasminogen activator and matrix metalloproteinase 2 and 9) involved in the metastasis and spread of cancer cells.
reduce the amount of vascular endothelial growth factor (VEGF), which develops new blood vessels to carry nutrients to developing tumors.
All these effects were seen in this animal study within 6 months of continuous infusion. While obviously impractical for humans, the study suggests that daily consumption of green tea may be highly protective.
Red wine
When researchers at the Fred Hutchinson Cancer Center in Seattle compared data on alcohol consumption collected from 753 prostate cancer patients aged 40-64 years old with similar data from a group of 703 age-matched controls without the disease, no clear association was seen between prostate cancer risk and overall alcohol consumption.
But, for each glass or red wine consumed per week, a 6% decrease was noted in the risk of developing prostate cancer, according to the study published in the January 2005 issue of the International Journal of Cancer.
Since no such association was seen with beer or other liquor, the researchers speculate that the flavonoids in red wine may help prevent tumor cell growth.
If you enjoy a glass of wine, choose red. And remember, benefits are seen with consumption of a glass or two daily-drinking more than 2 alcoholic beverages a day may be harmful to your health.
Lycopene
Lycopene is a "carotenoid," a natural antioxidant coloring found in fruits and vegetables that helps protect them from damage. In the body it is normally concentrated in the prostate and testes, and its consumption is associated with a lower prostate cancer risk. Interestingly, lycopene is the only carotenoid not found to be naturally lower in the blood of men versus women.
Low blood levels of lycopene are strongly associated with a higher risk for prostate cancer. These observations all seem to indicate a special protective role for lycopene in the hormone-sensitive prostate gland. Smoking, alcohol consumption, and lipid-lowering drugs decrease blood lycopene levels. But heating tomato foods before consumption and consuming tomato foods with moderate amounts of fat increases the bioavailability of lycopene.
More than 80 percent of lycopene consumed in the United States comes from tomatoes, although pink grapefruit, guava, and watermelon are also rich sources of lycopene.
Tomatoes have been shown to be helpful in reducing the risk of prostate cancer in men, and it was thought that their protective effect was primarily due to their lycopene content. However, a 14-month study published in the November 2003 issue of the Journal of the National Cancer Institute has underscored the importance of whole tomatoes, not lycopene alone, in the prevention of prostate cancer. In this study, rats fed a lycopene-rich diet and treated with N-methyl-N-nitrosourea (a carcinogen) and testosterone to induce prostate cancer had a similar risk of death from prostate cancer as rats fed a control diet. In contrast, rats fed whole tomato powder were 26% less likely to die of prostate cancer. By the end of the study, 80% of the control group and 72% of the rats fed lycopene had succumbed to prostate cancer, while only 62% of the rats fed whole tomato powder had died.
In addition to the controls and those rats receiving lycopene or tomato powder, each group was also divided into two sub-groups, one of which was given 20% less food than the other sub-group. Rats on the energy-restricted, tomato-based diet fared best of all, showing a 32% drop in their risk of dying from prostate cancer.
Researchers concluded this was due to the fact that tomatoes contain not merely lycopene, but a variety of protective phytochemicals and suggest that the lycopene found in human prostate tissue and the blood of animals and humans who remain free of prostate cancer may indicate exposure to higher amounts of not just lycopene but other compounds working in synergy with it. Study leader, Dr. Steven Clinton, Ohio State University, commented, "Our findings strongly suggest that risks of poor dietary habits cannot be reversed simply by taking a pill…if we want the health benefits of tomatoes, we should eat tomatoes or tomato products and not rely on lycopene supplements alone." In an accompanying editorial, Peter H. Gann, of the Robert H. Lurie Comprehensive Cancer Center at Northwestern University in Chicago, and Frederick Khachik, of the University of Maryland, College Park, remarked that this study supports those who advocate whole foods in the debate about whether cancer prevention is best achieved with whole foods or concentrated single compounds. They point out that carotenoids and other phytochemicals evolved as sets of interacting compounds, and that this complexity limits the usefulness of reductionist approaches that seek to identify single protective compounds.
More Studies Show Tomatoes Protective against Prostate Cancer
In animal studies, published in the April 14 on-line edition of the FASEB Journal (the official publication of the Federation of American Societies for Experimental Biology) lycopene and vitamin E were also found to reduce prostate cancer risk. Vitamin E reduced androgen (male hormone) signaling without affecting normal androgen metabolism, and lycopene down-regulated 5-alpha reductase, the enzyme that converts testosterone to the much more potent, and prostate cancer-promoting DHT. In addition, lycopene down-regulated the production in the prostate of two inflammatory chemicals, the cytokines IGF-I and IL-6, both of which are risk factors for prostate cancer.
A meta-analysis of 21 studies published in Cancer Epidemiology Biomarkers and Prevention confirms that eating tomatoes, especially cooked tomatoes, provides protection against prostate cancer. (Meta-analyses are considered the gold standard in medical research since, by combining the results of numerous studies, they integrate the results that occurred in different settings and include a much larger group of people, so they are thought to provide a more accurate assessment.)
When the data from all 21 studies was combined, men who ate the highest amounts of raw tomatoes were found to have an 11% reduction in risk for prostate cancer. Those eating the most cooked tomato products fared even better with a 19% reduction in prostate cancer risk. Even eating just one 6-ounce serving a day of raw tomato provided some benefit-a reduction in prostate cancer risk of 3%.
How Tomatoes Protect against Cancer
New research by Dr. Joseph Levy and colleagues from Ben-Gurion University of the Negev, Beer-Sheva, Israel, may have identified the unique mechanism through which lycopene protects against cancer: activating cancer-preventive phase II enzymes.
When the researchers incubated breast and liver cancer cells with lycopene, the carotenoid triggered the production and activity of the phase II detoxification enzymes (NAD(P)H:quinone oxidoreductase (NQ01) and glutamylcysteine synthetase (GCS). Lycopene ramped up production and activity of these protective enzymes by causing the expression of a reporter gene called luciferase that then activated the "antioxidant response element" in other genes that encode the enzymes, thus causing the genes to direct increased enzyme production.
In contrast, other carotenoids including beta-carotene, astaxanthin and phytoene did not have this effect. Since much epidemiological evidence indicates that lycopene acts synergistically with other phytochemicals to give tomatoes their protective effects, and recent studies have shown that eating tomato products prevents cancer more effectively than taking lycopene alone, the researchers concluded that other carotenoids stimulate phase II enzymes via different pathways from that used by lycopene.
Tomatoes and Broccoli Team Up to Fight Prostate Cancer
Tomatoes and broccoli-two vegetables separately recognized for their cancer-fighting capabilities-are even more successful against prostate cancer when working as a team in the daily diet, shows a study published in Cancer Research.
"When tomatoes and broccoli are eaten together, we see an additive effect. We think it's because different bioactive compounds in each food work on different anti-cancer pathways," said John Erdman, Professor of Food Science and Human Nutrition at the University of Illinois.
Starting one month before male rats were implanted with prostate tumors, Erdman and doctoral candidate Kirstie Canene-Adams fed the animals one of 5 different diets. Then they compared the cancer-preventive effects of the diets to treatment with finasteride, a drug commonly prescribed for men with enlarged prostates, or surgical castration.
The diets contained one of the following: 10% tomato, 10% broccoli, 5% tomato plus 5% broccoli, 10% tomato plus 10% broccoli, or lycopene (23 or 224 nmol/g diet).
The tomato and broccoli given as powders made from the whole vegetable to compare the effects of eating the whole food to simply consuming one active compound as a nutritional supplement- in this case, lycopene, a carotenoid found in tomatoes.
After 22 weeks, when the rats' were sacrificed and their prostate tumors weighed, the 10% tomato/broccoli combination was shown to greatly outperform all other diets, shrinking prostate tumors by 52%.
Broccoli alone decreased tumor weight by 42%, and tomato alone by 34%.
Lycopene alone (23 or 224 nmol/g diet) came in last, reducing tumor weight by 7% and 18% respectively.
Only castration-a last resort option for most men, although it resulted in a 62% reduction in prostate tumor weight-approached the level of protection delivered by the tomato/broccoli diet. Said Erdman, "As nutritionists, it was very exciting to compare this drastic surgery to diet and see that tumor reduction was similar."
"Older men with slow-growing prostate cancer who have chosen watchful waiting over chemotherapy and radiation should seriously consider altering their diets to include more tomatoes and broccoli," said Canene-Adams.
To get the prostate health benefits seen in this study, a 55-year-old man would need to consume 1.4 cups of raw broccoli and 2.5 cups of fresh tomato, 1 cup of tomato sauce or ½ cup of tomato paste daily, said Canene-Adams.
Erdman noted that this study shows eating whole foods is better than taking isolated nutrients. "It's better to eat tomatoes than to take a lycopene supplement-and cooked tomatoes may be better than raw tomatoes. Chopping and heating make the cancer-fighting constituents of tomatoes and broccoli more bioavailable," he said.
Practical Tips: While the phytonutrients in tomatoes become more concentrated when they are cooked into a sauce or paste, and more bioavailable when eaten with a little oil, those in broccoli will be greatly reduced if this vegetable is overcooked. Steam or healthy sauté broccoli no more than 5 minutes.
Also, broccoli's cancer-preventive compounds form after it has been cut, but heat denatures the enzyme necessary for this process. For optimal nutrient formation, cut broccoli florets in half or into quarters, depending on their initial size, and let sit for 5 minutes before cooking.
Broccoli and tomatoes can make a delicious team at virtually any meal or snack:
Healthy sauté broccoli and onion, then add to your favorite breakfast omelet and serve with grilled tomatoes.
Enjoy a bowl of tomato soup along with a salad including broccoli florets for lunch.
Add lightly steamed broccoli florets to the tomato-paste toppings on your favorite pizza.
Healthy sauté broccoli florets along with other favorite vegetables, such as onions and mushrooms, add to pasta sauce and use to top whole wheat pasta or brown rice.
For a quick snack, serve raw broccoli florets along with the carrot and celery sticks, dip and crackers, and toast your prostate's health with a glass of tomato juice.
The Right Amount of Vitamin D
A study published in the January 2004 issue of the International Journal of Cancer involving more than 2,000 men in Norway, Finland and Sweden, found that those whose blood levels of vitamin D were either too low (>19nmol/l) or too high (<80nmol/l) had an increased prostate cancer risk. Men whose average serum concentration of vitamin D ranged from 40-60 nmol/l had the lowest risk of prostate cancer. The researchers theorize that when vitamin D serum concentration is too low, this leads to low tissue concentration of vitamin D and weakened control of cell division in prostate cells. When vitamin D levels are too high, however, this may lead to an increase in the production of the enzyme 24-hyrdoxylase, which inactivates vitamin D.
So what does this mean in terms of how much vitamin D-rich food a man should eat? It depends upon where he lives and how old he is. Since the process through which our bodies make vitamin D begins when our skin is exposed to sunlight, regular consumption of foods rich in vitamin D is especially important for men who live in northern latitudes, are homebound, or wear sunscreen or clothing that completely covers the body. Regular consumption of vitamin D-rich foods is especially important for older men who live in northern latitudes since the production of vitamin D precursors in the skin, and thus our ability to make the vitamin, decreases with age.
Foods rich in vitamin D include sardines, salmon, tuna, shrimp, cod, snapper, halibut, eggs and vitamin D-fortified milk products. If these are all staples in your diet and you live in an area where sunshine is the norm year round, it might be wise to ask your doctor to check your serum concentration of 25(OH)-vitamin D to be sure it is not excessive. If you eat few of these foods and live in the sun-sparse north, you might also consider having your physician check to be sure your serum level of 25(OH)-vitamin D is not too low and adding a serving of vitamin D-rich food to your daily menu.
Vitamin E
In addition to its well-known protective effects on cardiovascular function, vitamin E may provide specific antioxidant protection for prostate health. Especially among smokers, low blood levels of vitamin E relate to a higher risk of death from prostate cancer, and higher blood levels correlate to a lower incidence of prostate cancer as well as a reduced risk of death from prostate cancer.
In the laboratory, prostate and breast cancer cells exposed to higher levels of vitamin E grow more slowly and are more likely to die than those exposed to lower levels. This fat-soluble vitamin is another important link in the nutritional chain of prostate protection.
Research presented at the annual meeting of the American Association for Cancer Research, held March 27-31, 2004, in Orlando, FL, found that people who eat the most vitamin E-containing foods are the least likely to have bladder or prostate cancer.
Bladder cancer, the fourth leading cause of death in men in the U.S. is also a leading cause of death in other industrialized countries such as Canada, France, Denmark, Italy, and Spain.
Reporting on the results of a study conducted at the University of Texas M.D. Anderson Cancer Center and Texas Woman's University, researcher Ladia M. Hernandez noted that "High intake of vitamin E from dietary sources alone was associated with a 42% reduced risk of bladder cancer, whereas high intake of vitamin E from dietary sources and supplements combined reduced the risk by 44%."
In the case control study from which these statistics were derived, Hernandez and colleagues developed a database based on published values of the tocopherol (vitamin E) content of foods and interviewed 468 bladder cancer patients and 534 healthy, cancer-free controls about their dietary and supplemental intake of the vitamin.
In a second study, data collected by researchers from the U.S. National Cancer Institute, the Fred Hutchinson Cancer Research Center and the National Public Health Institute of Finland showed that two vitamin E fractions, alpha- and gamma-tocopherol, lowered the risk of prostate cancer, alpha tocopherol by up to 53% and gamma-tocopherol by as much as 39%.
In this study, 100 men with prostate cancer and 200 without were selected from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29,133 Finnish men, aged between 50 and 69 years.
Prior to this, the ATBC study had already demonstrated a 32% reduction in the rate of prostate cancer in men who took 50 mg of the alpha-tocopherol fraction of vitamin E daily for a period of five to eight years.
In the new study, men not taking supplements were included to evaluate serum levels of alpha- and gamma-tocopherol derived from their diets. The men who were randomized to receive a vitamin E supplement as part of the ATBC trial and who also had the highest serum vitamin E levels at baseline, indicating their diets supplied the most vitamin E, were found to have the lowest risk of prostate cancer.
Taken together, the two studies appear to support an increase in dietary alpha-tocopherol, but it should be noted that this form of the vitamin is typically found in greater concentrations in the blood than the gamma form largely because a protein in the liver called "alpha-tocopherol transfer protein" binds alpha-tocopherol and transfers it into the plasma. Our thought at the World's Healthiest Foods is "Why limit yourself to one fraction of vitamin E when Mother Nature supplies them all, perfectly balanced in delicious foods?"
More Research Confirms Dietary Vitamin E Superior to Supplements for Protection against Prostate Cancer and Alzheimer's Disease
While the type of vitamin E usually used in supplements is alpha-tocopherol, research published in the December 2004 issue of the Proceedings of the National Academy of Sciences indicates another form of vitamin E, gamma-tocopherol, but not alpha-tocopherol, inhibits prostate cancer cell proliferation, without affecting healthy prostate cells.
Plus, the anti-cancer effect of gamma-tocopherol, when combined with other forms of vitamin E such as delta-tocopherol, appears to be additive.
Vitamin E is a generic term for a family of at least eight structurally related molecules. When the first research was conducted on vitamin E by the Shute brothers early in the 19th century, in rats, one fraction of vitamin E, alpha tocopherol, appeared more potent since it was necessary for successful pregnancy and production of rat offspring. For this reason, the Shutes named the vitamin "tocopherol," from the Greek word meaning "to give birth."
More recent research has revealed that, in humans, other vitamin E fractions may be even more beneficial. Gamma-tocopherol has been found to exhibit anti-inflammatory effects, which has led researchers to think this fraction may be more cardioprotective than the alpha-tocopherol found in most supplements. Not only is gamma-tocopherol anti-inflammatory, but it is also highly attracted to the nucleus in cells-the site where mutations in the genetic code can promote the development of cancer.
When Dr. Jiang and his team investigated the anti-carcinogenic potential of various forms of vitamin E, they found that gamma-tocopherol, particularly in combination with other forms of vitamin E such as delta-tocopherol, induced apoptosis (cell death) in androgen-sensitive prostate cancer cells within 3 days of treatment. Alpha-tocopherol alone did not have this effect.
The gamma and delta E fractions appear to induce apoptosis by interrupting the synthesis of sphingolipid, a fatty molecule in cell membranes that acts as a signaling messenger to modulate events inside the cell. In the cell membranes of human prostate cancer cells, the interruption of sphingolipid's synthesis by gamma and delta tocopherols causes the cancerous cells to self-destruct, while leaving healthy cells unaffected. Both fractions, as well as alpha tocopherol, are naturally present in foods rich in vitamin E, which include a number of greens (mustard greens, turnip greens, spinach, collard greens, and kale), sunflower seeds and almonds.
A high intake of vitamin E from food, but not from supplements (which usually contain just alpha-tocopherol) is also inversely associated with Alzheimer's disease. Rush University's Martha Clare Morris, Sc.D., lead nutrition researcher for CHAP, the Chicago Health and Aging Project, found a 67% lower risk of Alzheimer's in subjects with the highest intakes of vitamin E from food and concluded: "various tocopherol forms rather than alpha-tocopherol alone may be important in the vitamin E protective association with Alzheimer's disease."
A large human trial has now confirmed the results of earlier in vitro (test tube) and animal studies. In a 5-year study, researchers prospectively investigated if a link existed between intakes of the four tocopherol forms of vitamin E and risk of prostate cancer among 295,344 men, aged between 50 and 71, taking part in the NIH-AARP Diet and Health Study.
Vitamin E is found in 8 forms: 4 tocopherols (alpha, beta, gamma, delta) and 4 tocotrienols (alpha, beta, gamma, delta). Alpha-tocopherol is the main source in supplements; gamma-tocopherol is the most common form in the American diet.
Although regular intake of vitamin E supplements providing up to 800 IU per day did not affect prostate cancer risk, men eating the most foods providing gamma-tocopherol were found to have a 32% lower risk of advanced prostate cancer compared to men eating the least gamma-tocopherol-rich foods. (Wright ME, Weinstein SJ, et al., Cancer Epidemiol Biomarkers Prev.)
Practical Tip: Nuts and seeds are the most highly concentrated sources of gamma-tocopherol, especially walnuts, flaxseed, pecans, sesame seeds, and pumpkin seeds.
For an outstanding, vitamin E-rich dish you can prepare in less than 10 minutes, try steaming some whole kale leaves (5 minutes), transfer to a bowl, drizzle generously with olive oil, cut into bite-sized pieces, and toss with salt, pepper and walnuts or pumpkin seeds. If desired, top with a splash of lemon juice or balsamic vinegar (3-4 minutes).
Selenium
Selenium is a crucial antioxidant in the body, and higher selenium levels in the body are associated with lower risks for numerous cancers, including prostate cancer. It works closely with vitamin E, and seems to protect prostate (and other) cells and their genetic material from damage by free radicals, heavy metals, and toxins.
Because the evidence from earlier studies with vitamin E and selenium were so promising, a number of larger studies are now in progress, including the SELECT (Selenium and Vitamin E Cancer Prevention Trial) Prostate Cancer Prevention Trial, the largest trial of its kind to date.
Brassica family vegetables
The members of the brassica family (also called cruciferous) vegetables - including broccoli, kale, cauliflower, cabbage, mustard, horseradish, and Brussels sprouts, as well as broccoli sprouts - provide unique nutrients (called glucosinolates) that support your body's normal detoxification processes, which are necessary for maintaining healthy levels of both "male" and "female" hormones. Even within individual prostate cells, glucosinolates beneficially influence the metabolism of hormones, which may explain why a higher consumption of mustard family vegetables is associated with a lower risk for prostate cancer.
In fact, a study that compared the diets of 602 men under 65 years of age without prostate cancer to 628 men newly diagnosed with prostate cancer found that the men least likely to develop prostate cancer were those who ate three or more servings of cruciferous vegetables every week. These men had a 41% decreased risk of prostate cancer compared with men who ate less than one serving per week, even after the researchers accounted for total vegetable intake.
Indole-3-carbinol (I3C), a naturally occurring component of Brassica vegetables, such as cabbage, broccoli, and Brussels sprouts, has been recognized as a promising anticancer agent against certain reproductive tumor cells. A study published in the December 2003 issue of Cancer, the journal of the American Cancer Society, looked at I3C's effects on cell cycling progression and cancer cell proliferation in human prostate cancer cells. I3C was shown to suppress the growth of prostate cancer cells in a dose-dependent manner by blocking several important steps in cell cycling and also to inhibit the production of prostate specific antigen, a protein produced by the prostate whose rising levels may indicate prostate cancer. Researchers noted that the results of this study demonstrate that "I3C has a potent antiproliferative effect" in human prostate cancer cells, which qualifies it as "a potential chemotherapeutic agent" against human prostate cancer.
Cruciferous Vegetables Help Lower Risk of Certain Aggressive Prostate Cancers
Researchers from Canada and the U.S. evaluated the association between prostate cancer risk and intake of fruits and vegetables in 29,361 men in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. While there was no relationship found between overall prostate cancer risk and fruit and vegetable consumption, there was a relationship found between aggressive stage III and stage IV cancers that had expanded beyond the prostate gland (called extraprostatic prostate cancers) and vegetable intake. Consuming at least one weekly serving of cruciferous vegetables was associated with a near 40% reduction in risk of stage III and stage IV tumors risk, with broccoli and cauliflower offering the most protection. Men eating broccoli more than once a week were 45% less likely to develop stage III and IV prostate cancers, and eating cauliflower more than once a week conferred a 52% reduction in stage III and stage IV prostate cancer risk.(Kirsh VA,Peters U, et al., J Natl Cancer Inst.)
Vegetable Fiber
Not only how much fiber, but the source of the fiber a man consumes may affect his risk of prostate cancer, suggests a study published in the March 2004 issue of the International Journal of Cancer.
An Italian multi-center, case control study of 2,745 men aged 46-74 (1,294 men with prostate cancer and 1451 controls) found that while men with the highest intake of all kinds of fiber had a 7% lower risk of developing prostate cancer, those men who obtained most of their fiber from vegetables were 18% less likely to develop prostate cancer.
Fiber from fruits and grains was not associated with a reduction in prostate cancer risk. These associations held regardless of age, family history of prostate cancer, body mass index and education level.
Zinc
Zinc is used by the body in hundreds of processes, and is critical for the normal hormonal, immune system, and genetic function. It is concentrated more highly in the prostate than in any other human tissue, and low levels of zinc in the prostate relate to a higher risk for prostate cancer. Our intake of zinc usually decreases when we age, as does our absorption of zinc from food.
The Controversy over Fats, Fatty Fish, and Omega-3 Fats
No group of nutrients is more controversial than fats when it comes to prostate cancer risk. There are dozens of high-quality research studies in this area, but the results are largely conflicting and confusing. The only two factors that escape confusion are: (1) total amount of fat consumed and (2) amount of saturated fat consumed. If you want to lower your risk of prostate cancer, you need to avoid excessive fat intake, and you also need to avoid excessive intake of saturated fat. For the most part, this saturated fat will come from animal products such as high-fat meat, whole milk, or cream. But outside of these two fat-related factors, the evidence gets very controversial.
Omega-3 essential fats (such as occur in nuts, seeds, especially flaxseeds, and cold-water fish) are very important nutrients. Adequate intake of omega-3s is important for everyone, regardless of prostate cancer risk. However, for many health problems, increased consumption of omega-3s - even very great increases in consumption - lowers risk. This equation does not hold true for risk of prostate cancer risk. High intake of omega-3 fats - especially one specific omega-3 fatty acid called alpha-linolenic acid, or ALA - has been associated in several studies with increased risk of prostate cancer. However, other researchers have found no increase in risk from increased intake of ALA. Several researchers have criticized this whole area of dietary investigation with respect to prostate cancer. As a bottom line, it makes sense to consume ALA-rich foods (including flaxseeds, flax oil, walnuts, walnut oil, and canola oil) in adequate but limited amounts.
For other omega-3 fatty acids, including eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA - research results are also mixed. Many studies find no significant DHA or EPA impact in either direction. But these DHA and EPA studies are further complicated by studies involving risk of prostate cancer and fatty fish intake. Fatty fish like salmon contain especially high levels of DHA and EPA. If DHA and EPA were going to increase or decrease a man's risk of prostate cancer, you would expect high intake of fatty fish to increase or decrease that man's risk as well. In several research studies, fatty fish do not appear to have either effect on the majority of men. However, there is one particular group of men who do appear to have significantly decreased risk when they eat large amounts of fatty fish. This group of men have a particular genetic predisposition, that involves inheritance of an uncommon form of the enzyme cyclo-oxygenase-2 (COX-2). Unless a man knew that he possessed that COX-2 gene variant, he would probably do best to follow the same general advice for fatty fish, EPA, and DHA that applies to the ALA omega-3 fatty acid as well: keep intake EPA and DHA-rich foods (including fatty fish like salmon) to a moderate level, providing adequate but not high amounts of these omega-3 fatty acids.
More Omega-3s, Less Omega-6 Fatty Acids
The standard Western diet is high in omega 6 fatty acids and low in omega 3 fats, typically with an omega 6: omega 3 ratio of at least 20:1. Several recent studies strongly suggest that changing the diet to lower this ratio down towards the 2:1 ratio most scientists believe is ideal could significantly reduce PSA levels and prostate cancer tumor growth rates. (Kobayashi N, Barnard RJ, et al., Clin Cancer Res.); (Brown MD, Hart CA, et al., Br J Cancer).
In one study, researchers compared blood levels of polyunsaturated fats in 476 men diagnosed with prostate cancer and the same number of healthy controls. The highest blood levels of EPA and DHA, the omega-3 fats found in cold water fish, were associated with a 41% reduction in prostate cancer risk, while the highest levels of omega-6 fats correlated with greatly increased risk of prostate cancer. Increased blood levels of the omega-6 metabolites, gamma-linolenic acid and dihomo-gamma-linolenic acid, were associated with a 41% and 54% increase in prostate cancer risk, respectively. To lower your risk of prostate cancer, eat more omega-3 rich fish, and consume less foods rich in omega-6 fats, such meats and products made with corn and safflower oils. (Chavarro JE, Stampfer MJ, et al., Cancer Epidemiol Biomarkers Prev.)
New Research Approach Underscores the Synergistic Fffects of the World's Healthiest Foods: Tomatoes and Broccoli Team Up to Provide Greater Cancer Protection
Finally, a study has examined the effect of eating whole foods in combination instead of isolated nutrients, and guess what-the beneficial synergy among nutrients that results when we consume a variety of healthful foods has got taking single nutrients beat by a mile.
According to this research, presented July 15, 2004, at the two-day WCRF/AICR International Research Conference on Food, Nutrition and Cancer in Washington, D.C., eating broccoli along with tomatoes maximizes the cancer protection both foods provide.
In the study, which will be published in the December 2004 issue of the Journal of Nutrition, rats fed a tomato-and-broccoli combo had way less prostate tumor growth than rats given diets containing either food alone or normal rat chow diets supplemented with lycopene (a cancer-fighting carotenoid isolated from tomatoes) or finasteride (the drug commonly prescribed to men with benign prostatic hyperplasia or BPH).
When the results were analyzed, the researchers were surprised to find that all of the diets (tomato-and-broccoli, tomato, broccoli, and lycopene) were more effective in suppressing prostate tumor growth than the drug (finasteride).
At a press conference, lead researcher John W. Erdman, Ph.D., Professor of Food Science and Human Nutrition at the University of Illinois at Urbana, explained the rationale behind the new approach to nutrition research:
"We decided to look at these foods in combination because we believed it was a way to learn more about real diets eaten by real people. People don't eat nutrients, they eat food. And they don't eat one food; they eat many foods in combination."
Erdman also noted, "Studies that examine individual substances in isolation are simply not designed to tell us anything about the interactions that occur between those substances, much less between foods that each contains its own anti-cancer arsenal."
Erdman and his colleagues may have been inspired to try this novel approach by research they published in the November 2003 in the Journal of the National Cancer Institute. In this study, lycopene alone offered rats little protection from prostate cancer, while diets containing freeze-dried tomato powder greatly improved their prostate cancer survival.
In the new study, Erdman chose to combine tomatoes with broccoli, another food with well-studied anti-cancer effects. Compounds in broccoli called glucosinolates are converted in the intestines into compounds that increase liver enzymes' ability to clear carcinogens before they can cause harm.
Erdman was quick to assert that the food synergy between tomatoes and broccoli is not unique, that "This interactivity is likely taking place in any diet high in a variety of plant foods - fruits, vegetables, whole grains and beans."
His colleague, Jeff Prince, Vice-President for Education at the American Institute for Cancer Research, echoed Erdman's belief:
"The take-home message isn't just about tomatoes and broccoli. The inferences to be drawn are more tentative and a lot broader.
A lycopene supplement may not hurt you, but the whole tomato can help you more. A whole tomato may help you, but a tomato eaten with broccoli will help you more. Tomato with broccoli may help you, but a medley of different vegetables eaten together will bolster the body's different defenses against chronic disease."
Special note on Vegetarian Diet and Stress Reduction
We often hear that vegetarian eating is good and that stress management is good, but in combination, they appear to be particularly good for men who have already had prostate cancer.
A recent small study looked at men previously treated for prostate cancer (their prostates were removed) yet showed elevated levels of PSA (prostate-specific antigen), a laboratory screening marker for prostate cancer. They were considered to be in the early stages of recurrence of prostate cancer and at increased risk for the cancer spreading to other parts of the body, a fate shared by more than one-third of men treated for prostate cancer.
These men followed a low-fat, high-fiber, plant food-based diet (rich in whole grains, beans, fresh vegetables, soyfoods, and fruit, and restricted in caffeine, animal foods, and processed foods) combined with a stress reduction program. After four months, tumor growth had slowed, the men lost weight, and in some cases their PSA levels had even decreased - all beneficial results for the men.
Nutrient Excesses
Moderate your intake of fat, including polyunsaturated fat
Total fat in the diet has one of the strongest links to hormone-related diseases like prostate cancer and breast cancer. This may be for a number of related reasons. Obviously, fats are energy-rich and are easy for the body to store as excess body fat, which is related to a wide range of health problems. Additionally, these stored fats send biochemical messages throughout your body that influence your hormone status and balance, the way you use food energy, and even how your immune system works.
What is somewhat surprising in the case of prostate cancer, however, is the increased risk that can come from excessive intake of polyunsaturated fats, especially those containing very high amounts of omega 6 fatty acids. In a study published in the February 2004 issue of Cancer Research, mice with advanced human prostate cancer that were deprived of testosterone and fed a diet low in polyunsaturated fats remained in remission and lived nearly twice as long as mice given a diet high in polyunsaturated fat. In addition, levels of PSA (prostate specific antigen), a measure of the level of prostate cancer present, were much lower in the mice on the low polyunsaturated fat diet.
Research published in Carcinogenesis shows that when arachidonic acid, which is made in the body from omega-6 fatty acids, is introduced to human prostate cancer cells in tissue culture, the result is increased growth of prostate cancer cells.
According to Dr. William Aronson, a Professor of Urology at the UCLA Jonsson Cancer Center, several lines of research point to the role of excessive fat, excessive polyunsaturated fat, and excessive omega-6 polyunsaturated fat in elevated risk of prostate cancer. The body's inflammatory system and androgen hormone metabolism are both seen as likely mechanisms that give these excessive fats a means of increasing prostate problems. According to Dr. Aronson, "I think dietary fat reduction, coupled with high fiber intake from fruits and vegetables in a variety of colors, can truly have an impact on prostate cancer prevention, and in combination with existing treatments, perhaps increase survival times for patients."
Animal foods
Animal foods (meat in particular, but also milk, eggs, and cheese) are key dietary sources of saturated fats and cholesterol, both of which are implicated in the development of prostate and cardiovascular diseases.
Additionally, animals raised for meat are sometimes given hormones to stimulate their growth or are exposed to other agricultural chemicals whose residues may be stored in their flesh. Non-organic milk can also be a potential dietary source of cadmium stemming from environmental pollution. Intake of this heavy metal is also associated with prostate disease.
While organic animal foods are preferable to non-organic, they still contain saturated fats and cholesterol. For prevention of prostate conditions, it is best to limit your intake of animal foods and to instead base your diet on plant foods.
Dairy products
Like fatty fish and omega-3 fatty acids, the impact of dairy products on prostate cancer risk has been controversial in research studies. All whole milk dairy products contain significant amounts of total fat and saturated fat. In addition, most dairy products contain significant amounts of calcium. Under certain circumstances, each of these nutrients can increase risk of prostate cancer when consumed in excessive amounts. Until research issues in this area of dairy products become more clear, men wanting to minimize their risk of prostate cancer would do best to consume dairy products in moderation.
Fried, broiled, and grilled meats
Carcinogenic compounds from fried, broiled, and grilled meats have been shown in the laboratory to cause prostatic DNA mutations as well as prostate tumors. African-American men ingest more of these meats and their carcinogens than do Caucasian American men, which may partly explain why prostate cancer mortality in African-American men is double that of Caucasian American men.
Recommended Diet
Dietary guidelines for prostate health and function include:
Eat fresh and organic foods whenever possible
Enjoy grapefruit as a breakfast juice, add segments to salads, have a half grapefruit as a first course
Eat legumes regularly, especially organic soyfoods (tofu, tempeh, edamame, etc)
Eat fresh vegetables every day, especially mustard family vegetables (broccoli, cauliflower, kale, cabbage, Brussels sprouts, etc.) Men eating 4 servings of vegetables daily have almost half the risk for prostate cancer as men eating less than 2 servings of vegetables daily
Limit your intakes of animal foods, especially animal fat, dairy foods, and red meat
Stick with low-to-moderate intake of cold-water fish like salmon
Enjoy avocados frequently
Eat tomato products frequently (excellent source of lycopene)
Eat whole-grain rice, pasta, cereals, breads, and crackers; suggestion: have whole-grains (like rice, quinoa, or pasta) with tomato sauce, olive oil, garlic, onions, spices, and organic tofu (or other soyfood) a few times weekly
Eat nuts and seeds regularly, especially ground flaxseed-for essential fats, selenium, zinc, vitamin E, dietary fiber, and phytosterols
Enjoy fresh or dried fruit for dessert, especially whole cranberries
If you eat meat, focus on fish and organic game and poultry rather than red meats
Use spices every day, especially rosemary, ginger, garlic, turmeric, basil, sage, thyme, oregano, curry spice (spices like these support hormone metabolism and excretion), and red chili pepper (lowers PSA)
Drink green tea
Enjoy a glass or two of red wine each day
In Sum: A Heart Healthy Diet May Be Good for the Prostate
The type of diet normally prescribed for cardiovascular health-high in vegetables and lean protein, low in fat and red meat-along with moderate alcohol consumption (no more than 2 drinks a day) significantly decreases the risk of benign prostatic hyperplasia, or BPH. (Kristal AR, Arnold KB, et al. Am J Epidemiol.) BPH is associated with frequent and painful urination and affects about half of all men by age 50 and almost all men by age 70.
Researchers at the Fred Hutchinson Cancer Research Center in Seattle analyzed data on 4,770 subjects in the Prostate Cancer Prevention Trial, a large randomized clinical trial to determine whether finasteride, a drug used to treat BPH, would also prevent prostate cancer. The men involved in this analysis, all 55 and older, participated in the placebo arm of the finasteride trial. All were free of BPH symptoms at the start of the study and received annual screening for signs of prostate enlargement.
The results showed:
A high-fat diet increased the risk of BPH by 31%
Daily consumption of red meat increased BPH risk by 38%
Eating four or more servings of vegetables daily reduced BPH risk by 32%
Consuming high amounts of lean protein (about 20% of daily calorie intake) lowered BPH risk by 15%
Regular, moderate alcohol consumption (no more than two drinks a day) reduced BPH risk by 38%.
A Fat Chance for BPH
Risk of BPH rose incrementally as fat intake increased, reaching a more than 30% increase in BPH risk among men who got about 40% of their calories from fat.
"We don't really know how working, but it's pretty clear that eating a high amount of fat, and it doesn't appear to matter what kind of fat, increases the risk of BPH," said lead researcher Alan Kristal.
High fat intake promotes BPH because too much dietary fat (and obesity-too much body fat) increases the body's overall inflammatory response and also increases levels of circulating hormones such as estrogens and androgens, both of which affect prostate tissue. In contrast, a low fat, high vegetable and moderate alcohol consumption pattern is associated with less obesity, less inflammation, and lower circulating estrogens and androgens.
Moderate alcohol consumption may help protect against BPH because it lowers levels of circulating hormones (including testosterone) and decreases muscle tone in the prostate.
The study found no evidence that supplemental antioxidants decreased risk, and only weak evidence to suggest supplemental zinc, lycopene or vitamin D might reduce risk.
Practical Tip: A healthy way of eating that includes lots of vegetables along with lean protein and one or two drinks a day (we suggest red wine for its many resveratrol-related benefits) was clearly highly protective.
Editor - Tavaris Long
VS 
OR 
