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Prostate Cancer, Nutrition, and Dietary Supplements (PDQ®)
- Overview of CAM Use in Prostate Cancer
- Questions and Answers About Green Tea
- Questions and Answers About Lycopene
- Questions and Answers About Modified Citrus Pectin
- Questions and Answers About Pomegranate
- Questions and Answers About Soy
- Questions and Answers About Zyflamend
- Changes to This Summary (01/10/2013)
- General CAM Information
- Evaluation of CAM Approaches
- Questions to Ask Your Health Care Provider About CAM
- To Learn More About CAM
- About PDQ
Men in the United States get prostate cancer more than any other type of cancer except skin cancer. It is found mainly in older men. In the United States, about one out of five men will be diagnosed with prostate cancer. Most men diagnosed with prostate cancer do not die of it.
Complementary and alternative medicine (CAM) is a form of treatment used in addition to (complementary) or instead of (alternative) standard treatments. CAM treatments generally are not considered standard medical approaches. Standard treatments go through a long and careful research process to prove they are safe and effective, but less is known about most types of CAM.
This PDQ CAM summary gives general information about using foods and dietary supplements to lower the risk of developing prostate cancer or for treating prostate cancer, its symptoms, or side effects of disease treatment. In addition, this summary has sections for six specific foods or dietary supplements:
- Green Tea
- Modified Citrus Pectin
More topics will be added over time. These sections include the following information for each food or dietary supplement:
- How it is given or consumed.
- Reviews of laboratory and animal studies.
- Results of population studies and clinical trials.
- Side effects or risks.
- Food and Drug Administration (FDA) information.
Overview of CAM Use in Prostate Cancer
- Men who have prostate cancer are more likely to take dietary supplements than men who do not have prostate cancer.
- Prostate cancer patients with the healthiest eating habits (for example, eating lots of fish rich in omega-3 fatty acids and vegetables) are the most likely to take dietary supplements.
- Popular dietary supplements used by prostate cancer patients include lycopene, vitamin E, selenium, and saw palmetto.
- Reasons given by prostate cancer patients for using CAM treatments include boosting the immune system, improving quality of life, and lowering the risk of the cancer coming back.
Studies of CAM use to lower the risk of developing prostate cancer or to prevent it from coming back have shown the following:
- A study of men with a family history of prostate cancer found that over half used vitamins or other dietary supplements, including those sold for prostate health or cancer prevention such as selenium, green tea, and saw palmetto.
- A study of men at a prostate cancer screening clinic found that well over half took multivitamins and a smaller number took herbal supplements.
- A study of prostate cancer survivors found that up to one-third took vitamins or minerals.
- Although many prostate cancer patients use CAM therapies, only about half of them tell their doctors about their use of CAM.
Studies of why prostate cancer patients do or don't decide to use CAM show that their choice is based on many factors, including their medical history, their beliefs about the safety and side effects of CAM compared to standard treatments, and their need to feel in control of their treatment.
Questions and Answers About Green TeaWhat is green tea? Tea has been consumed in Asia since ancient times. Sailors first brought tea to England in the 17th century. Other than water, tea is the most widely consumed beverage in the world. All tea comes from the Camellia sinensis plant. The way the leaves of this plant are processed determines the type of tea produced. To make green tea, the tea leaves are steamed and dried; this causes very little oxidation (a chemical reaction that takes place when a substance comes into contact with oxygen or another oxidizing substance). Black tea is made by crushing tea leaves to cause full oxidation. Oolong tea is made from partially oxidized leaves.Some studies suggest that green tea may protect against cardiovascular disease and some types of cancer. Clinical trials designed to study whether green tea is useful in treating prostate cancer are in the early stages. There is not enough evidence to show whether green tea is effective in treating prostate cancer.Many of the possible health benefits studied in tea are thought to be from compounds called polyphenols. Polyphenols are a large group of plant chemicals that include catechins (antioxidants that help protect cells from damage caused by free radicals).The most active catechin in green tea is epigallocatechin-3-gallate (EGCG). How is green tea administered or consumed? Green tea may be consumed as a beverage or taken in dietary supplements. Have any preclinical (laboratory or animal) studies been conducted using green tea? Laboratory and animal research has been done to study the effects of green tea in prostate cancer. Studies of green tea in the laboratory have shown the following: EGCG was shown to block the stimulating effect of androgen (a male sex hormone) on human prostate tumor cells, slow their spread, and increase cell death.Human prostate cancer cells were treated with EGCG for 30 minutes and then with radiation. Cells treated with EGCG were less likely to die when exposed to radiation than cells not treated with EGCG before radiation.Prostate cancer cells were treated with either EGCG or EGCG-loaded nanoparticles. While both treatments decreased cell spread and increased cell death, the nanoparticle treatment was more effective at lower levels, suggesting this type of delivery system for EGCG may make it easier for the body to use and improve EGCG's anticancer activity.Green tea polyphenols may cause anticancer effects by blocking histone deacetylases (HDAC) which are found in large amounts in cancer cells, including those in prostate cancer. Treating prostate cancer cells with green tea polyphenols lowered HDAC activity and caused cell death.Studies of green tea in animal models of prostate cancer have shown the following: Strains of mice created to develop prostate cancer that acts like human cancer were given either plain water or water treated with green tea catechins (comparable to a human drinking 6 cups of green tea/ day). After 24 weeks, the mice given plain water had developed prostate cancer while the mice given water with green tea catechins showed only prostatic intraepithelial neoplasia (PIN) lesions. The findings suggested that green tea catechins may help delay the development of prostate cancer by blocking a protein involved in cancer growth. Mice were implanted with prostate cancer cells and injected with EGCG or placebo 3 times/ week. The mice that received the EGCG treatment had lower levels of proteins needed for androgen activity than those treated with placebo. The findings suggested that EGCG blocks the stimulating effect of androgen on tumor cells in a way that may be useful in prostate cancer that can be treated with hormone therapy and also in prostate cancer that does not respond to hormone therapy.Strains of mice created to develop prostate cancer that acts like human cancer were given green tea polyphenols in drinking water starting at different ages (to match different stages of prostate cancer). All the green tea-fed mice were tumor-free longer than water-fed control mice, but the mice that were fed with green tea the earliest benefitted the most. The findings suggested that green tea might be most beneficial either in men diagnosed with early PIN lesions, men at high risk for developing prostate cancer, or men undergoing watchful waiting. In another study, these strains of mice were given EGCG in drinking water (comparable to a human drinking 6 cups of green tea/ day) starting at either 12 weeks of age or 28 weeks of age. EGCG treatment prevented high-grade PIN lesions in mice that began treatment at 12 weeks but not in those that began treatment at 28 weeks of age. Have any clinical trials (research studies with people) of green tea been conducted? Population studies and clinical trials have been done to find out if green tea may be useful in preventing or treating prostate cancer.Population studiesPopulation studies look for risk factors and ways to control disease in large groups of people.A review of many population studies combined, mainly from Asia, suggested that green tea may help protect against prostate cancer in Asian populations. Black tea was not found to affect prostate cancer risk.Clinical trials of preventing prostate cancerA study assigned 60 men with high-grade prostatic intraepithelial neoplasia (HGPIN) to take green tea catechin capsules (600 mg/ day) or a placebo. After 1 year, 9 men in the placebo group were diagnosed with prostate cancer compared to 1 man in the green tea catechin group. The findings suggest that green tea catechins may lower the risk of prostate cancer in patients at high risk for the disease. Two year follow-up showed that this effect was long-lasting. A larger, multicenter trial is underway.Clinical trials of treating prostate cancer Clinical trials designed to study whether green tea is useful in treating prostate cancer have shown the following:Patients scheduled to undergo radical prostatectomy were assigned to drink green tea, black tea, or soda five times/ day for 5 days. Bioavailable tea polyphenols were found in prostate tissue samples of patients who drank either green tea or black tea. In addition, prostate cancer cells treated with blood taken from patients after they drank tea grew and divided more slowly than cells treated with blood taken from patients before they drank tea. Fifty patients scheduled to undergo radical prostatectomy were assigned to take Polyphenon E (800 mg EGCG) or a placebo daily for 3 to 6 weeks. Patients treated with Polyphenon E had lower blood levels of prostate specific antigen (PSA) and insulin-like growth factor-1 (a protein linked with increased risk of prostate cancer) than patients treated with placebo, but these differences were not meaningful. The findings suggest that the possible anticancer effects of green tea polyphenols may need to be studied in longer treatment trials.A small group of hormone-refractory prostate cancer patients were given capsules of green tea extract (375 mg of polyphenols/ day) for up to 5 months. The study showed that the green tea treatment was well tolerated by most of the patients. However, no patient had a meaningful decrease in PSA levels and all 19 patients had disease progression within 1 to 5 months. Patients with androgen-independent prostate cancer that had spread to other places in the body consumed green tea (6 grams/ day). Of the forty-two participants, one had a meaningful decrease in blood PSA levels which did not last longer than 2 months. Green tea was well tolerated by most of the study patients. However, there were 6 reports of serious side effects, including insomnia, confusion, and fatigue. The findings suggest that green tea may have limited benefits in patients with advanced prostate cancer. Have any side effects or risks been reported from green tea? Green tea has been well tolerated in clinical studies of patients with prostate cancer. One study found that the most commonly reported side effects of green tea were gastrointestinal symptoms. These were mild except for two reports of severe anorexia and moderate breathing problems. There is evidence that consuming 10 or more cups of green tea/ day for long periods of time does not cause ill effects and that any side effects that do occur are due to caffeine content in the tea. Is green tea approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States? The U.S. Food and Drug Administration has not approved the use of green tea as a treatment for cancer or any other medical condition. Green tea is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.
Current Clinical Trials
General information about clinical trials is also available from the NCI Web site.
Questions and Answers About LycopeneWhat is lycopene? Lycopene is a carotenoid (a natural pigment made by plants). Lycopene protects plants from stress and helps them use the energy of the sun to make nutrients. Lycopene is found in fruits and vegetables like tomatoes, apricots, guavas, and watermelons. The main source of lycopene in the American diet is tomato-based products. Lycopene is more bioavailable (easier for the body to use) in processed tomato products like tomato paste and tomato puree than in raw tomatoes. Eating carotenoids, including lycopene, along with dietary fat may help the body absorb them. For example, one study showed that more lycopene was absorbed from diced tomatoes cooked with olive oil than diced tomatoes cooked without olive oil.Lycopene in the diet may affect antioxidant activity and communication between cells. Laboratory and animal studies have shown that lycopene may help lower the risk of prostate, skin, breast, lung, and liver cancers. However, clinical trials of whether lycopene lowers cancer risk have shown mixed results. How is lycopene administered or consumed? Lycopene may be consumed in the diet or taken in dietary supplements. Have any preclinical (laboratory or animal) studies been conducted using lycopene? Laboratory research and animal studies have been done to find out if lycopene may be useful in preventing or treating prostate cancer.Studies of lycopene in the laboratory have shown the following: Prostate cancer cells treated with lycopene had changes in their cell division cycle, leading to less cancer cell growth.In prostate cancer cells treated with lycopene, cholesterol levels were lower, leading to less cancer cell growth & more cancer cell damage.Treating prostate cancer cells with lycopene may change the way androgen (male hormone) is taken up and used in the cells, causing less cancer cell growth.Combining lycopene with standard cancer drugs may help stop the growth of different types of prostate cancer cells more than when drugs are used alone. Used together with a cancer drug, lycopene may block the way insulin-like growth factor (IGF) is taken up by the cells, causing less cancer cell growth.Studies of animal models of prostate cancer treated with lycopene have shown the following: Strains of mice created to develop prostate cancer that acts like human cancer were fed a diet with either lycopene beadlets or tomato paste. Mice on the lycopene beadlet diet had a greater decrease in prostate cancer rates than mice on the tomato paste diet. This suggests that lycopene might have more cancer protective effects than tomato paste. Combining lycopene with a substance found in dried tomatoes (FruHis) slowed the growth of prostate cancer cells in rats more than either lycopene or FruHis alone.A study of mice injected with human prostate cancer cells showed that mice treated with either lycopene or beta carotene supplements had less tumor growth.A study of mice injected with human prostate cancer cells and treated with a certain chemotherapy drug, lycopene, or both showed that those treated with chemotherapy and lycopene lived longer and had smaller tumors than those treated with chemotherapy alone. Have any population studies or clinical trials (research studies with people) of lycopene been conducted? Several population studies and clinical trials have been done to find out if lycopene may be useful in preventing or treating prostate cancer.Population studies Population studies look for risk factors and ways to control disease in large groups of people. Population studies of prostate cancer risk have shown the following mixed results: Studies of large groups of men have not found a link between levels of lycopene in the blood and the risk of developing prostate cancer.Several studies found that men who ate more tomatoes had a slightly lower risk of prostate cancer.A study found no link between lycopene and tomatoes in the diet and prostate cancer risk in the overall population. However, in men with a family history of the disease, higher amounts of lycopene in the diet were linked with a lower risk of prostate cancer. Another study in the same group of men found no difference in blood levels of lycopene between healthy men and men who developed prostate cancer. Clinical trials of preventing prostate cancerClinical trials designed to study whether lycopene is useful in preventing prostate cancer have shown the following: Men with benign prostate hyperplasia (BPH) or prostate cancer were given tomato sauce dishes for 3 weeks before scheduled surgery to remove the prostate. The study found that they had lower prostate specific antigen (PSA) levels and more cancer cell death found in the prostate when examined after surgery than a similar group of patients who did not receive the tomato sauce dishes.Men with high-grade prostatic intraepithelial neoplasia (HGPIN) who took lycopene supplements for 2 years had a greater decrease in PSA levels and fewer cases of prostate cancer than those who did not. This indicated that lycopene may be useful in preventing HGPIN from developing into prostate cancer. In another study of men at high risk of prostate cancer (such as men with HGPIN), those who took a daily multivitamin with no lycopene and those who took the same multivitamin plus lycopene (30 mg/ day) for 4 months showed no difference in PSA levels.Clinical trials of treating prostate cancerClinical trials designed to study whether lycopene is useful in treating prostate cancer have shown the following: Men with prostate cancer that had not spread were given lycopene supplements (30mg/ day) for 3 weeks before surgery to remove the prostate. Those who received lycopene supplements had smaller tumors and lower PSA levels than those who did not. This study suggests that lycopene may be helpful in treating prostate cancer. Another study of men with prostate cancer that had not spread showed that men who took lycopene supplements (10mg/ day) had lower PSA velocity (a measure of how fast PSA levels in the blood increase over time) after treatment. Men who had biochemical relapse of prostate cancer (a rise in the blood level of PSA after treatment with surgery or radiation) were given different doses of lycopene supplements (ranging from 15 mg/ day to 120 mg/ day) for 1 year. Study results showed that lycopene seemed safe & had no side effects, but did not change PSA levels in biochemically relapsed prostate cancer.Men with hormone-refractory prostate cancer (HRPC) (tumors that do not respond to treatment with hormones) were given lycopene supplements for periods of 3 or 6 months in 2 different studies. These studies showed mixed results in lowering PSA levels in men with HRPC.Men with androgen-independent prostate cancer (tumors that do not need androgen to grow) consumed lycopene in either tomato paste or tomato juice daily for 4 months. Study results showed that lycopene may not be effective in lowering PSA levels in androgen-independent cancer. Have any side effects or risks been reported from lycopene? Lycopene has been consumed by prostate cancer patients with very few side effects in many clinical trials. Doses ranging from 10 to 120 mg/ day have caused only occasional gastrointestinal symptoms (e.g. diarrhea, nausea and vomiting, bloating, gassiness and stomach irritation). In one study, symptoms went away when lycopene was taken with meals. Is lycopene approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States? The U.S. Food and Drug Administration has not approved the use of lycopene as a treatment for cancer or any other medical condition.Lycopene is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made. An FDA review in 2007 found that there was not enough evidence to allow a claim that lycopene helps lower cancer risk.
Current Clinical Trials
General information about clinical trials is also available from the NCI Web site.
Questions and Answers About Modified Citrus PectinWhat is modified citrus pectin? Pectin is a type of polysaccharide (a carbohydrate with many small sugar molecules that are chemically linked). Pectin is found in the cell walls of most plants and has gel-like qualities that are useful in making many types of food and medicine.Citrus pectin is found in the peel and pulp of citrus fruits such as oranges, grapefruit, lemons, and limes. Citrus pectin can be modified with high pH and heat to break its molecules into smaller pieces. Modified citrus pectin (also called MCP) can be digested and absorbed by the body. How is MCP administered or consumed? MCP may be taken by mouth in powder or capsule form. Have any preclinical (laboratory or animal) studies been conducted using MCP? A study in prostate cancer cells compared 3 different kinds of pectin: citrus pectin, PectaSol (a dietary supplement with MCP), and fractionated pectin powder. Prostate cancer cells treated with the pectin powder had more damage than those treated with citrus pectin or PectaSol. However, when citrus pectin was modified by heating it, it caused the same amount of damage to prostate cancer cells as the pectin powder. Only a few studies have reported the effects of MCP in animal models of cancer, including one prostate cancer study. Rats injected with prostate cancer cells and treated with MCP showed less spread of the cancer to the lungs but no effect on tumor growth at the original cancer site. Have any population studies or clinical trials (research studies with people) of MCP been conducted? A few studies in prostate cancer patients suggest that MCP may have some anticancer benefits.In a study of patients with advanced solid tumors, including prostate cancers, MCP powder in water was given 3 times/ day for at least 8 weeks. The study showed some quality of life improvements in physical functioning, overall health, fatigue, pain, and insomnia. About one-fourth of patients showed stable disease after 8 weeks of treatment and a smaller number had stable disease for more than 24 weeks. Since the study did not include a group of patients who did not receive MCP for comparison, it was not designed to be able to tell if any of these changes were due to the addition of MCP. The primary goal of the study was to determine if MCP would be well tolerated by cancer patients, and it was. In a study of the effect of MCP on prostate-specific antigen (PSA) doubling time (how long it takes PSA levels in the blood to increase by 100 percent), prostate cancer patients who had rising PSA levels were given 6 PectaSol capsules 3 times/ day for 12 months. After treatment, 7 out of 10 patients showed a slowing of PSA doubling time. Have any side effects or risks been reported from MCP? Two studies of MCP showed that most patients had very few side effects. Itching, stomach upset, and gassiness were reported in one study. In another study, 3 patients had abdominal cramps and diarrhea that went away when their treatment was stopped. Is MCP approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States? The U.S. Food and Drug Administration has not approved the use of MCP as a treatment for cancer or any other medical condition.MCP is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.
Current Clinical Trials
General information about clinical trials is also available from the NCI Web site.
Questions and Answers About PomegranateWhat is pomegranate? The pomegranate fruit (Punica granatum L.) is native to Asia and grown throughout the Mediterranean, Southeast Asia, East Indies, Africa, and the United States. Pomegranate has been used for medicinal purposes since ancient times. Different parts of the pomegranate fruit have bioactive compounds (chemicals found in small amounts that have actions in the body that may promote good health). These include: the peel, which makes up half the fruit and contains bioactive compounds such as phenolics, flavonoids, and ellagitannins (the main source of antioxidant activity);the seeds, which contain punicic acid, an omega-5 fatty acid; andthe aril (outer layer surrounding the seeds), which contains phenolics and flavonoids including anthocyanins, which give the pomegranate fruit and juice their red color. How is pomegranate administered or consumed? Pomegranate may be consumed in the diet or taken in dietary supplements. Have any preclinical (laboratory or animal) studies been conducted using pomegranate? Laboratory studies of pomegranate in cancer cell lines include the following: A study of 13 pomegranate compounds showed some were able to slow the growth and spread of prostate cancer cells and to cause cell death. Higher doses were found to be more effective. Punicic acid (a bioactive compound found in pomegranate seeds) was shown to have the strongest effect in causing cell death.Three types of prostate cancer cell lines were treated with either pomegranate extract, pomegranate juice, or two of their bioactive compounds. All pomegranate treatments were shown to increase cell death and decrease the spread of cancer cells, with higher doses found to be more effective. In the cell line that was dependent on androgen (male hormone) for growth, all treatments affected the way androgen was taken up and used.Other studies in cancer cell lines found that the anticancer activity of pomegranate included effects on certain enzymes and pathways involved in cancer, such as the insulin-like growth factor (IGF) system. Studies of animal models of prostate cancer in which the animals were given pomegranate have shown the following: A study of mice injected with prostate tumor-forming cells found that mice that drank pomegranate extract in water had tumors that were smaller and took longer to develop than tumors in mice that drank normal water.In a study of strains of mice created to develop prostate cancer that acts like human cancer, all mice that were given normal water for 28 weeks developed tumors. Only one-fifth to one-third of the mice that received pomegranate extract in water developed tumors, with the mice that received the highest amounts of pomegranate extract having the fewest tumors. Have any clinical trials (research studies with people) of pomegranate been conducted? Two clinical trials that studied pomegranate in prostate cancer patients have been fully reported. In a study of patients with rising prostate-specific antigen (PSA) levels after surgery or radiation therapy, patients were given 8 ounces of pomegranate juice daily for up to 33 months. Drinking pomegranate juice was related to a slowing of PSA doubling time (how long it takes PSA levels in the blood to increase by 100 percent). In addition, when prostate cancer cells (LNCaP) in the lab were treated with study patients’ blood before and after the study, there was a decrease in cell growth and increase in cell death following pomegranate treatment.In a study of patients with rising PSA levels after therapy for localized prostate cancer, patients were given 1 gram or 3 gram doses of pomegranate extract. Both doses of pomegranate extract were related to a slowing of PSA doubling time. Have any side effects or risks been reported from pomegranate? Two studies of pomegranate juice in either prostate cancer patients or patients with erectile dysfunction reported no serious side effects. Is there any reason people should avoid pomegranate juice?Some pomegranate products may contain added sugar. Certain groups, such as the American Institute for Cancer Research (AICR), recommend avoiding sugary drinks. For more information, see the AICR website. Is pomegranate approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States? The U.S. Food and Drug Administration has not approved the use of pomegranate as a treatment for cancer or any other medical condition. Pomegranate is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.
Current Clinical Trials
Check NCI’s list of cancer clinical trials for CAM clinical trials on pomegranate-extract pill for prostate cancer, pomegranate juice for prostate cancer, and pomegranate liquid extract for prostate cancer that are actively enrolling patients.
General information about clinical trials is also available from the NCI Web site.
Questions and Answers About SoyWhat is soy? The soybean plant has been grown in Asia for food since ancient times. Soy first arrived in Europe and North America in the 18th century. The soybean can be processed into a wide variety of products including soy milk, miso, tofu, soy flour, and oil. Soy foods contain many phytochemicals that may have health benefits. Isoflavones are the most widely researched compounds in soy. Major isoflavones in the soybean include genistein (which may be the most bioactive isoflavone), daidzein, and glycitein. Isoflavones protect the soybean plant from stress and have antioxidant, antimicrobial, and antifungal actions.Isoflavones are phytoestrogens (estrogen-like substances found in plants) that attach to estrogen receptors in cells. Genistein has been shown to affect many pathways in prostate cancer cells involved in the growth and spread of cancer. How is soy administered or consumed? Soy may be consumed in the diet or taken in dietary supplements. Have any preclinical (laboratory or animal) studies been conducted using soy? Laboratory research and animal studies have been done to find out if soy may be useful in preventing or treating prostate cancer.Studies of soy in the laboratory have shown the following: Several laboratory studies have found that treating human prostate cancer cells with isoflavones (such as genistein or daidzein) interferes with pathways in prostate cancer cells related to inflammation and cancer growth and spread.Some laboratory studies have found that treating prostate cancer cells with whole soy extract (containing all the major isoflavones) or combining other plant-based compounds with isoflavones may have more anticancer effects than using single isoflavones. One study compared treating human prostate cancer cells with soy isoflavones, curcumin (a yellow pigment of the spice turmeric that is being studied in cancer prevention), or a combination of the two compounds. Results showed that combining curcumin and isoflavones was more effective in lowering prostate-specific antigen (PSA) levels than using either compound alone.Studies of animal models of prostate cancer treated with soy have shown the following mixed results: Strains of mice created to develop prostate cancer that acts like human cancer were fed a diet with genistein or a control diet. Compared with mice on the control diet, the mice fed the genistein diet had less prostate cancer cell growth and lower levels of growth promoting proteins. A study of mice that were genetically modified to produce prostate cancer found that mice fed a low-dose genistein diet had more spread of cancer than mice fed either a high-dose genistein diet or a diet with no genistein. This suggests that the effects of genistein on prostate cancer may vary depending on dose and on how early it is given.A study in mice implanted with advanced human prostate cancer found that those given daily genistein in peanut oil developed more tumors in other parts of the body than mice given peanut oil without genistein.In a study of combining radiation therapy with soy isoflavones, mice implanted with prostate cancer cells were treated with genistein, mixed isoflavones (genistein, daidzein, and glycitein), and/ or radiation. Mixed isoflavones were found to be more effective than genistein in slowing prostate tumor growth. Combining mixed isoflavones with radiation was found to be most effective in slowing tumor growth. Have any population studies or clinical trials (research studies with people) of soy been conducted? Many population studies and clinical trials have been done to find out if soy may be useful in preventing or treating prostate cancer. Soy products studied include dietary supplements, drinks, and bread.Population studies Population studies look for risk factors and ways to control disease in large groups of people. Population studies of soy intake and prostate cancer risk have shown the following: A review of many studies combined showed that men eating large amounts of nonfermented soy foods (for example, tofu and soybean milk) had a lower risk of prostate cancer. Eating large amounts of fermented foods (for example, miso) was not found to affect the risk of prostate cancer.Clinical trials of preventing prostate cancer In a study of Japanese men who underwent a prostate biopsy but who did not have cancer, some received a daily supplement of soy isoflavones (40 mg) and curcumin (100 mg), while others received a placebo. After 6 months, there were no differences in PSA levels between the supplement group and the placebo group overall. However, among patients with higher PSA levels at the start, those who received the supplement had meaningful decreases in PSA levels compared to patients in the placebo group.A study was done to find out if a soy diet standard in Asia would be practical for European men to follow. Healthy men ate either a high-soy (2 daily soy servings) or low-soy (usual) diet for 3 months, then crossed over to the other diet. Lower PSA levels were seen with the high-soy diet. Results showed that study volunteers were able to follow the high-soy diet.Men at risk for prostate cancer or with low-grade prostate cancer were given either soy protein, alcohol-washed soy protein (which is lower in isoflavones), or milk protein (which has no isoflavones) for 6 months. PSA levels did not differ among the groups at 3 months or 6 months. Fewer cases of prostate cancer were found after 6 months in men who consumed either type of soy protein than in men who consumed milk protein.Clinical trials of treating prostate cancer In a trial of soy isoflavones, prostate cancer patients with rising PSA levels who had been treated with radiation therapy consumed a soy drink daily for 6 months. The soy drink contained 65-90 mg of isoflavones. Results showed that the soy drink had very few side effects and slowed PSA doubling time (how long it takes PSA levels in the blood to increase by 100 percent). These findings indicate that consuming the soy drink may have helped slow the progression of prostate cancer.In a trial of genistein (a major isoflavone), prostate cancer patients scheduled for radical prostatectomy received either a placebo or genistein (30 mg/ day) for 3-6 weeks before surgery. PSA levels in patients who received genistein decreased slightly while PSA levels in those who received the placebo increased slightly.A trial of a soy protein supplement (containing 60 mg/ day of isoflavones) studied patients with early-stage prostate cancer. Those who received the supplement for 12 weeks had slightly greater decreases in PSA and testosterone levels than those who received placebo. These results suggest that soy may help slow the progression of prostate cancer.Trials of whole soy were done in men scheduled for surgery to remove the prostate. In one study, patients given soy supplements for 2 weeks before surgery showed much higher levels of isoflavones in prostate tissue than in blood. In another study, patients who ate high-phytoestrogen bread (containing soy or soy and linseed) had greater decreases in PSA levels than those who ate wheat bread.A trial of a soy isoflavone supplement was done in prostate cancer patients receiving antiandrogen therapy. Side effects of antiandrogen therapy may include sexual dysfunction, lower quality of life, and changes in mental functioning. Men who received the isoflavone supplement (160 mg/day) for 12 weeks showed no improvement in side effects of antiandrogen therapy compared to men who received a placebo. Have any side effects or risks been reported from soy? Soy products and isoflavones have been consumed by prostate cancer patients with very few side effects in many clinical trials. The most commonly reported side effects were minor gastrointestinal symptoms. Is soy approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States? The U.S. Food and Drug Administration has not approved the use of soy as a treatment for cancer or any other medical condition. Soy is available in the United States in food products and dietary supplements. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.
Current Clinical Trials
General information about clinical trials is also available from the NCI Web site.
Questions and Answers About ZyflamendWhat is Zyflamend? Zyflamend is a dietary supplement that contains 10 different herbs. Zyflamend contains extracts of rosemary, turmeric, ginger, holy basil, green tea, hu zhang (Polygonum cuspidatum, a source of resveratrol), Chinese goldthread, barberry, oregano, and Baikal skullcap.The extracts found in Zyflamend have anti-inflammatory activity and possible anticancer benefits. There is limited evidence about how Zyflamend may act against tumor growth. Zyflamend has been shown to interfere with the activity of COX-1 and COX-2 enzymes, which are involved in the development of inflammation and possibly cancer. Zyflamend may also act against the NF-kappa B and lipoxygenase (LOX) families of proteins that stimulate tumor growth. How is Zyflamend administered or consumed? Zyflamend is taken as a dietary supplement in capsule form. Have any preclinical (laboratory or animal) studies been conducted using Zyflamend? Laboratory and animal research has recently been done to study the effects of Zyflamend in cancer.Studies of Zyflamend in the laboratory have shown the following: Human prostate cancer cells treated with different doses of Zyflamend had lower androgen (male hormone) receptor and prostate-specific antigen (PSA) levels compared with cells treated with a control substance; higher doses of Zyflamend were found to be more effective. Prostate cancer cells treated with both Zyflamend and bicalutamide (a nonsteroidal antiandrogen drug) showed lower levels of cell growth, PSA, and cancer survival proteins than prostate cancer cells treated with Zyflamend or bicalutamide alone.A study of the effects of Zyflamend on COX-1 and COX-2 activity in human prostate cancer cells found that Zyflamend was effective in blocking COX activity; higher doses were found to be more effective. Zyflamend was also found to limit the growth of prostate cancer cells. However, the prostate cancer cells in the study did not have high levels of COX-2, suggesting that Zyflamend may have effects on prostate cancer cells that are not related to COX activity.Prostate cancer cells were treated with insulin-like growth factor-1 (IGF-1, a protein linked with increased risk of prostate cancer) alone or together with Zyflamend. Cells treated with IGF-1 alone grew and spread more, while cells treated with both IGF-1 and Zyflamend grew and spread less. Zyflamend was also shown to decrease levels of the IGF-1 receptor and androgen receptor in prostate cancer cells. Studies of Zyflamend in animal models of cancer have shown the following:Mice implanted with pancreatic tumor cells received either Zyflamend or a control treatment. The mice treated with Zyflamend showed lower levels of cancer survival proteins and higher levels of anticancer activity than mice in the control group. Mice implanted with pancreatic tumor cells received either Zyflamend, gemcitabine, or both. Tumor cells from mice that received the combination of Zyflamend and gemcitabine showed a much greater decrease in tumor growth than tumor cells from mice that received Zyflamend or gemcitabine alone. The findings suggested that Zyflamend may have made the pancreatic tumors more sensitive to treatment with gemcitabine. Have any clinical trials (research studies with people) of Zyflamend been conducted? A report of one patient with high-grade prostatic intraepithelial neoplasia (HGPIN) who received Zyflamend 3 times/ day for 18 months showed that PSA levels were not affected. However, at the end of 18 months of treatment, repeat biopsies of the prostate did not show HGPIN or cancer. In a phase I safety study of Zyflamend, patients with HGPIN took Zyflamend (780 mg) 3 times/ day for 18 months with additional dietary supplements (probiotic supplement, multivitamin, green and white tea extract, Baikal skullcap, docosahexaenoic acid, holy basil, and turmeric). Zyflamend and the added dietary supplements were well tolerated and there were no serious side effects. At the end of 18 months of treatment, more than half of patients had benign biopsy results, about one-fourth had HGPIN, and about one in 8 had prostate cancer. Have any side effects or risks been reported from Zyflamend? A phase I safety study of Zyflamend (described above) reported no toxicity or serious side effects. Some of the patients had mild heartburn that went away when Zyflamend was taken with food. Is Zyflamend approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States? The U.S. Food and Drug Administration has not approved the use of Zyflamend as a treatment for cancer or any other medical condition.Zyflamend is available in the United States as a dietary supplement. Because dietary supplements are regulated as foods, not as drugs, FDA approval is not required unless specific claims about disease prevention or treatment are made.
Changes to This Summary (01/10/2013)
Changes were made to this summary to match those made to the health professional version.
General CAM Information
Complementary and alternative medicine (CAM)—also referred to as integrative medicine—includes a broad range of healing philosophies, approaches, and therapies. A therapy is generally called complementary when it is used in addition to conventional treatments; it is often called alternative when it is used instead of conventional treatment. (Conventional treatments are those that are widely accepted and practiced by the mainstream medical community.) Depending on how they are used, some therapies can be considered either complementary or alternative. Complementary and alternative therapies are used in an effort to prevent illness, reduce stress, prevent or reduce side effects and symptoms, or control or cure disease.
Unlike conventional treatments for cancer, complementary and alternative therapies are often not covered by insurance companies. Patients should check with their insurance provider to find out about coverage for complementary and alternative therapies.
Cancer patients considering complementary and alternative therapies should discuss this decision with their doctor, nurse, or pharmacist as they would any therapeutic approach, because some complementary and alternative therapies may interfere with their standard treatment or may be harmful when used with conventional treatment.
Evaluation of CAM Approaches
It is important that the same rigorous scientific evaluation used to assess conventional approaches be used to evaluate CAM therapies. The National Cancer Institute (NCI) and the National Center for Complementary and Alternative Medicine (NCCAM) are sponsoring a number of clinical trials (research studies) at medical centers to evaluate CAM therapies for cancer.
Conventional approaches to cancer treatment have generally been studied for safety and effectiveness through a rigorous scientific process that includes clinical trials with large numbers of patients. Less is known about the safety and effectiveness of complementary and alternative methods. Few CAM therapies have undergone rigorous evaluation. A small number of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that may help patients feel better and recover faster. One example is acupuncture. According to a panel of experts at a National Institutes of Health (NIH) Consensus Conference in November 1997, acupuncture has been found to be effective in the management of chemotherapy-associated nausea and vomiting and in controlling pain associated with surgery. In contrast, some approaches, such as the use of laetrile, have been studied and found ineffective or potentially harmful.
The NCI Best Case Series Program, which was started in 1991, is one way CAM approaches that are being used in practice are being investigated. The program is overseen by the NCI’s Office of Cancer Complementary and Alternative Medicine (OCCAM). Health care professionals who offer alternative cancer therapies submit their patients’ medical records and related materials to OCCAM. OCCAM conducts a critical review of the materials and develops follow-up research strategies for approaches deemed to warrant NCI-initiated research.
Questions to Ask Your Health Care Provider About CAM
When considering complementary and alternative therapies, patients should ask their health care provider the following questions:
- What side effects can be expected?
- What are the risks associated with this therapy?
- Do the known benefits outweigh the risks?
- What benefits can be expected from this therapy?
- Will the therapy interfere with conventional treatment?
- Is this therapy part of a clinical trial?
- If so, who is sponsoring the trial?
- Will the therapy be covered by health insurance?
To Learn More About CAM
National Center for Complementary and Alternative Medicine (NCCAM)
The National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health (NIH) facilitates research and evaluation of complementary and alternative practices, and provides information about a variety of approaches to health professionals and the public.
- NCCAM Clearinghouse
- Post Office Box 7923 Gaithersburg, MD 20898–7923
- Telephone: 1–888–644–6226 (toll free) 301–519–3153 (for International callers)
- TTY (for deaf and hard of hearing callers): 1–866–464–3615
- Fax: 1–866–464–3616
- E-mail: firstname.lastname@example.org
- Web site: http://nccam.nih.gov
CAM on PubMed
NCCAM and the NIH National Library of Medicine (NLM) jointly developed CAM on PubMed, a free and easy-to-use search tool for finding CAM-related journal citations. As a subset of the NLM's PubMed bibliographic database, CAM on PubMed features more than 230,000 references and abstracts for CAM-related articles from scientific journals. This database also provides links to the Web sites of over 1,800 journals, allowing users to view full-text articles. (A subscription or other fee may be required to access full-text articles.) CAM on PubMed is available through the NCCAM Web site. It can also be accessed through NLM PubMed bibliographic database by selecting the "Limits" tab and choosing "Complementary Medicine" as a subset.
Office of Cancer Complementary and Alternative Medicine
The NCI Office of Cancer Complementary and Alternative Medicine (OCCAM) coordinates the activities of the NCI in the area of complementary and alternative medicine (CAM). OCCAM supports CAM cancer research and provides information about cancer-related CAM to health providers and the general public via the NCI Web site.
National Cancer Institute (NCI) Cancer Information Service
U.S. residents may call the NCI Cancer Information Service toll free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 8:00 am to 8:00 pm. A trained Cancer Information Specialist is available to answer your questions.
Food and Drug Administration
The Food and Drug Administration (FDA) regulates drugs and medical devices to ensure that they are safe and effective.
- Food and Drug Administration
- 5600 Fishers Lane
- Rockville, MD 20857
- Telephone: 1–888–463–6332 (toll free)
- Web site: http://www.fda.gov/
Federal Trade Commission
The Federal Trade Commission (FTC) enforces consumer protection laws. Publications available from the FTC include:
- Who Cares: Sources of Information About Health Care Products and Services
- Fraudulent Health Claims: Don’t Be Fooled
- Consumer Response Center
- Federal Trade Commission
- Washington, DC 20580
- Telephone: 1-877-FTC-HELP (1-877-382-4357) (toll free)
- TTY (for deaf and hearing impaired callers): 202-326-2502
- Web site: http://www.ftc.gov/
PDQ is a comprehensive cancer database available on NCI's Web site.
PDQ is the National Cancer Institute's (NCI's) comprehensive cancer information database. Most of the information contained in PDQ is available online at NCI's Web site. PDQ is provided as a service of the NCI. The NCI is part of the National Institutes of Health, the federal government's focal point for biomedical research.
PDQ contains cancer information summaries.
The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries are available in two versions. The health professional versions provide detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions provide current and accurate cancer information.
Images in the PDQ summaries are used with permission of the author(s), artist, and/or publisher for use within the PDQ summaries only. Permission to use images outside the context of PDQ information must be obtained from the owner(s) and cannot be granted by the National Cancer Institute. Information about using the illustrations in the PDQ summaries, along with many other cancer-related images, are available in Visuals Online, a collection of over 2,000 scientific images.
The PDQ cancer information summaries are developed by cancer experts and reviewed regularly.
Editorial Boards made up of experts in oncology and related specialties are responsible for writing and maintaining the cancer information summaries. The summaries are reviewed regularly and changes are made as new information becomes available. The date on each summary ("Date Last Modified") indicates the time of the most recent change.
PDQ also contains information on clinical trials.
A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Listings of clinical trials are included in PDQ and are available online at NCI's Web site. Descriptions of the trials are available in health professional and patient versions. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237).
This information was last updated on 2013-01-10