がん情報サイト | がん情報各論：[患者さん向け]Prostate Cancer, Nutrition, and Dietary Supplements (PDQ®)

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This PDQ cancer information summary has current information about the use of nutrition and dietary supplements for reducing the risk of developing prostate cancer or for treating prostate cancer. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Date Last Modified") is the date of the most recent change. The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board.

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Introduction

Complementary and alternative medicine (CAM) is a form of treatment used in addition to (complementary) or instead of (alternative) standard treatments.

In the United States, about 1 out of every 8 men will be diagnosed with prostate cancer. It is the most second-most common cancer in men in the United States. CAM use among men with prostate cancer is common. Studies of why men with prostate cancer decide to use CAM show that their choice is based on medical history, beliefs about the safety and side effects of CAM compared to standard treatments, and a need to feel in control of their treatment.

CAM treatments used by men with prostate cancer include certain foods, dietary supplements, herbs, vitamins, and minerals.

Different types of research have been done to study the use of CAM in prostate cancer. These study types include the following:

Combined study: A combined study analyzes data from more than one study done on the same topic, such as the response to a dietary supplement, risk of getting cancer, or treatment of cancer. The results of a combined study are usually stronger than the results of any study by itself. A combined study is also called a meta-analysis.
Population study: A population study looks at a group of people who are part of the general population and share a common characteristic, such as age, sex, or health condition. This group of people may be studied for different reasons, such as their response to a dietary supplement or risk of getting cancer. A population study is also called an epidemiologic study.
Clinical trial: A clinical trial looks at how well new medical approaches work in people. These studies may test new methods of screening, prevention, diagnosis, or treatment of cancer. Clinical trials with a small number of people or when the treatment is not randomly assigned are not included in this summary. See the clinical trial sections of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements for information on clinical trials done using nutrients or supplements.
Laboratory and animal studies: In laboratory studies, tumor cells are used to test a substance to find out if it is likely to have any anticancer effects. In animal studies, tests are done to see if a drug, procedure, or treatment is safe and effective in animals. Laboratory and animal studies are done before a substance is tested in people.

CAM treatments have been studied to see if their use lowers the risk of prostate cancer, kills prostate cancer cells, or lowers the risk that cancer will come back after treatment. Most of these studies used prostate-specific antigen (PSA) levels to find out whether the treatment worked. This is a weaker measure of how well the treatment works than direct measures, such as fewer new cases of prostate cancer, or smaller tumor size or lower rate of recurrence after treatment for prostate cancer.

This PDQ summary has sections about the use of specific foods and dietary supplements to prevent or treat prostate cancer:

Each section includes the following information for each food or dietary supplement:

Overview of CAM Use in Prostate Cancer

Studies of CAM use to treat prostate cancer have shown the following:

Studies of CAM use to lower prostate cancer risk or to prevent it from coming back have shown the following:

See the PDQ summary on Prostate Cancer Prevention for more information on prostate cancer prevention.

Calcium: Questions and Answers

1.What is calcium?

Calcium is a common mineral in the body that is needed to help blood vessels, muscles, and nerves work to send signals from cell to cell, and to release hormones. The body stores most calcium in bones and teeth.

2.How is calcium given or taken?

The main sources of calcium are in foods and dietary supplements. About one-third of dietary calcium comes from milk and milk products like cheese and yogurt. Vegetable sources include Chinese cabbage, kale, and broccoli. Foods may have calcium added, such as fruit juices and drinks, tofu, and cereals.

Most research about calcium and prostate cancer risk has studied calcium in the diet and not calcium in supplements.

3.Have any laboratory or animal studies been done using calcium?

For information on laboratory and animal studies done using calcium, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of calcium been done in people?

Studies of people in many parts of the world have been done to find out if there is a link between dairy products, calcium, and prostate cancer risk. The results of these studies have been mixed. Some studies have shown that calcium has an effect on the overall risk of developing prostate cancer or on stopping cancer from coming back after treatment, and others have not. Several studies have suggested that eating a large amount of calcium may increase the risk of advanced and metastatic prostate cancer.

Combined studies

A 2005 review found a possible link between an increased risk of prostate cancer and a diet high in dairy products and calcium.
A review of studies published between 1996 and 2006 found that milk and dairy products in the diet increased the risk of prostate cancer.
A 2008 review of 45 studies found no link between dairy products and the risk of prostate cancer.
A 2013 review for the U.S. Preventive Services Task Force found that taking vitamin D and/or calcium supplements showed no overall effect on rates of cancer or deaths from cancer, including prostate cancer.
A 2015 review of 32 studies found that high amounts of milk, low-fat milk, cheese, total dietary calcium, and dairy calcium in the diet may increase the risk of prostate cancer. Calcium supplements and non-dairy calcium were not linked with an increased risk of prostate cancer.

Population studies

Clinical trials

5.Is calcium approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

The FDA has not approved the use of calcium as a treatment for cancer.

The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of calcium supplements may not be the same.

Current Clinical Trials

Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.

Green Tea: Questions and Answers

1.What is green tea?

Tea comes from the Camellia sinensis plant. The way tea leaves are processed determines whether green tea, black tea, or oolong tea is made. Green tea is made by steaming and drying the leaves.

The health benefits studied in green tea are thought to be from compounds called polyphenols. Polyphenols are a group of plant chemicals that include catechins (antioxidants that help protect cells from damage). Catechins make up most of the polyphenols in green tea and vary based on the source of the tea leaves and how they are processed. This makes it hard to identify most of the chemical factors linked to the health benefits of green tea.

Some studies have suggested that green tea may protect against heart and blood vessel disease.

2.How is green tea given or taken?

People usually drink green tea or take it as a dietary supplement.

3.Have any laboratory or animal studies been done using green tea?

For information on laboratory and animal studies done using green tea, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of green tea been done in people?

Population studies and clinical trials have been done to find out if green tea can prevent or treat prostate cancer. Results have been mixed; some studies have shown a short-term decrease in prostate-specific antigen (PSA) level or a lower risk of having prostate cancer, and others have not. There is not enough evidence to know whether green tea can prevent or treat prostate cancer.

Population studies

Clinical trials

5.Have any side effects or risks been reported from green tea?

A trial of oral green tea extract in patients with solid tumors reported that drinking 7 to 8 Japanese-style cups (equal to 3 ½ to 4 cups U.S.) of tea 3 times a day for 6 months was a safe dose.

Clinical trials have reported on the safety of long-term use of green tea to prevent prostate cancer. In a United States trial, men at risk of prostate cancer were given green tea extract or a placebo for 1 year. There were more side effects in the group who received the green tea extract than in the group who received the placebo.

In safety studies of green tea for men with prostate cancer, short-term green tea use for up to 90 days was well tolerated. One study found that the most reported side effects of green tea were headache, chest pain, or gastrointestinal symptoms, such as nausea and diarrhea. These were mild except for two reports of trouble breathing and severe anorexia. In men with advanced prostate cancer, side effects reported include insomnia, confusion, and fatigue. In rare cases, liver problems have occurred.

6.Is green tea approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

The FDA has not approved the use of green tea as a treatment for cancer or any other medical condition.

The FDA Division of Drug Oncology Products recommends that green tea extract be taken with food by participants in clinical trials and that frequent liver function tests be considered during treatment, especially in the first few months of starting a clinical trial.

Green tea is available in the United States in food products and dietary supplements. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of green tea supplements may not be the same.

Current Clinical Trials

Lycopene: Questions and Answers

1.What is lycopene?

Lycopene is a carotenoid (a natural red color made by plants). It mixes with or dissolves in fats. Lycopene protects plants from light-related 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 United States is tomato-based products. Lycopene is easier for the body to use when it is eaten in processed tomato products like tomato paste and tomato puree than in raw tomatoes.

Lycopene has been studied for its role in the prevention of heart and blood vessel disease.

2.How is lycopene given or taken?

Lycopene may be eaten in food or taken in dietary supplements.

3.Have any laboratory or animal studies been done using lycopene?

For information on laboratory and animal studies done using lycopene, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of lycopene been done in people?

Population studies and clinical trials have been done to find out if lycopene can prevent or treat prostate cancer. Clinical trials have shown mixed results; some studies have shown a lower risk of prostate cancer or a decrease in prostate-specific antigen (PSA) level, and others have not. There is not enough evidence to know whether lycopene can prevent or treat prostate cancer.

Population and combined studies

Some population studies in men have found that high amounts of lycopene in the diet are linked with a lower risk of prostate cancer.
Some studies have shown that lycopene levels in the blood and tissue of people with cancer are lower than in those who do not have cancer. However, other studies have not shown this.
Reviews done in 2015 and 2017 of combined studies analyzed lycopene in the diet and lycopene levels in the blood. Both reviews found that higher lycopene intake and higher blood levels of lycopene were linked with lower prostate cancer risk.
A 2006 study done in men who took part in the National Cancer Institute's Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial found no link between lycopene and tomatoes in the diet and prostate cancer risk in men with no family history of prostate cancer. 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.

Sources and types of lycopene, types of diets, genetic risk factors, obesity, tobacco and alcohol use, and other factors, may play a part in mixed study results. Most research has studied the effects of lycopene on the risk of all prostate cancers, and has not studied effects of lycopene on low-grade prostate cancer compared with high-grade prostate cancer.

There are other trials of combination therapies that include lycopene in the Combination Therapies section of this summary.

5.Have any side effects or risks been reported from lycopene?

Lycopene has been given in many clinical trials with very few side effects. Side effects, such as diarrhea, nausea and vomiting, bloating, increased gas, and stomach irritation have been reported. In one study, symptoms went away when lycopene was taken with meals.

6.Is lycopene approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

The FDA has not approved the use of lycopene as a treatment for cancer or any other medical condition.

Lycopene is deemed Generally Recognized as Safe by the FDA.

Lycopene is available in the United States in food products and dietary supplements. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of lycopene supplements may not be the same.

Current Clinical Trials

Modified Citrus Pectin: Questions and Answers

1.What is modified citrus pectin?

Pectin is a substance made of small sugar molecules that are linked together. Pectin is found in the cell wall 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 (changed) during manufacturing so that it can be dissolved in water and absorbed by the body. This changed citrus pectin is called modified citrus pectin (MCP).

2.How is MCP given or taken?

MCP may be taken by mouth in powder or capsule form.

3.Have any laboratory or animal studies been done using MCP?

For information on laboratory and animal studies done using MCP, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of MCP been done in people?

Few studies have been done in men with prostate cancer. There is not enough evidence to know whether MCP has any effect on prostate cancer.

5.Have any side effects or risks been reported from MCP?

Side effects that have been reported include itching, stomach upset, abdominal cramps, increased gas, and diarrhea.

6.Is MCP approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

The FDA 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. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of MCP supplements may not be the same.

Current Clinical Trials

Pomegranate: Questions and Answers

1.What is pomegranate?

The pomegranate is a fruit grown in Asia and in the Mediterranean, East Indies, Africa, and the United States. Pomegranate has been used as medicine for hundreds of years.

The pomegranate is made up of the following:

2.How is pomegranate given or taken?

Pomegranate fruit and juice may be taken as food, drink, or a dietary supplement.

3.Have any laboratory or animal studies been done using pomegranate?

For information on laboratory and animal studies done using pomegranate, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of pomegranate been done in people?

In a 2015 study, 183 men with recurrent prostate cancer were randomly assigned to receive either pomegranate juice, pomegranate extract, or a placebo. The study found no difference in how fast the prostate-specific antigen (PSA) level rose between the 3 groups. There is not enough evidence to know whether pomegranate can prevent or treat prostate cancer.

5.Have any side effects or risks been reported from pomegranate?

No serious side effects have been reported from the use of pomegranate.

6.Is pomegranate approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

The FDA 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. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of pomegranate supplements may not be the same.

Current Clinical Trials

Selenium: Questions and Answers

1.What is selenium?

Selenium is a mineral that is essential to people in tiny amounts. Selenium is needed for many body functions, including reproduction and immunity. Food sources of selenium include meat, vegetables, and nuts. The amount of selenium found in the food depends on the amount of selenium in the soil where the food grows. Selenium is stored in the thyroid gland, liver, pancreas, pituitary gland, and kidneys.

Selenium may play a role in many diseases, including cancer. Results of the large National Cancer Institute-sponsored Selenium and Vitamin E Cancer Prevention Trial (SELECT) suggest that men with prostate cancer should not take selenium supplements.

2.How is selenium given or taken?

Selenium may be eaten in food or taken in dietary supplements.

3.Have any laboratory or animal studies been done using selenium?

For information on laboratory and animal studies done using selenium, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of selenium been done in people?

Population studies and clinical trials have been done to find out if selenium can prevent or treat prostate cancer. The results of these studies have been mixed, but the results of a large, randomized clinical trial showed selenium had no effect on preventing prostate cancer.

Combined studies

Population studies

The Selenium and Vitamin E Cancer Prevention Trial (SELECT)

SELECT was a large clinical trial begun by the National Cancer Institute in 2001 to find out whether selenium and/or vitamin E could help prevent prostate cancer when taken as dietary supplements. Over 35,000 men, aged 50 years and older, were randomly assigned to receive one of the following combinations daily for 7 to 12 years:

Early results of SELECT reported in 2009 found no difference in the rate of prostate cancer among the 4 groups. In the selenium alone group, there was a slight increase in the rate of diabetes mellitus. Even though this change was not clearly shown to be due to the supplement, the men in the study were advised to stop taking the study supplements.

Updated results of SELECT in 2011 showed that selenium supplements had no effect on prostate cancer risk.

In 2014, further results of SELECT showed that selenium supplements in men with low selenium levels at the start of the trial had no effect on prostate cancer risk. However, selenium supplements in men who had high levels of selenium at the start of the trial increased the risk of aggressive prostate cancer.

A study of 1,434 men in SELECT suggested that changes in certain genes which control the way selenium is used by the body may have an effect on the risk of prostate cancer.

Several factors may have affected study results, including the dose of vitamin E and the form of selenium used. The authors concluded that men should avoid selenium at doses that are higher than the recommended dietary intake.

5.Have any side effects or risks of selenium supplements been reported?

Selenium supplements have been well tolerated in many clinical trials. But, in the SELECT trial, the use of selenium supplements was linked with a slight increase in the rate of diabetes mellitus.

In several large studies, men with high selenium levels were at greater risk of being diagnosed with aggressive prostate cancer or dying from prostate cancer.

6.Is selenium approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

The FDA has not approved the use of selenium supplements for the treatment or prevention of cancer.

Selenium is available in the United States in food products and dietary supplements. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of selenium supplements may not be the same.

Current Clinical Trials

Soy: Questions and Answers

1.What is soy?

The soybean plant has been grown in Asia for food for hundreds of years. The soybean can be made into products, such as soy milk, miso, tofu, soy flour, and oil.

Soy foods contain phytochemicals that may have health benefits. Isoflavones are the most widely studied compounds in soy. Major isoflavones in the soybean include genistein, daidzein, and glycitein.

Isoflavones are phytoestrogens (estrogen-like substances found in plants) that attach to estrogen receptors found in prostate cancer cells. Genistein may affect some processes inside prostate cancer cells that are involved in the growth and spread of cancer.

2.How is soy given or taken?

Soy may be eaten in food or taken in dietary supplements.

3.Have any laboratory or animal studies been done using soy?

For information on laboratory and animal studies done using soy, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of soy been done in people?

Population studies and clinical trials have been done to find out if soy can prevent or treat prostate cancer. The results of these studies have been mixed. Some studies have shown a lower risk of prostate cancer or a change in prostate-specific antigen (PSA) level, and others have not. The results may be mixed because of the small number of men who participated in the studies and the different types and doses of soy products given.

Combined population studies

Clinical trials

Small randomized clinical trials have been done to study the effects of isoflavones or soy on prostate cancer. The results of these studies have been mixed. See Table 3, Table 4, and Table 5 of the health professional version of this summary for information on randomized, placebo-controlled clinical trials of isoflavones and soy.

5.Have any side effects or risks been reported from soy?

Soy products and isoflavones have been taken by prostate cancer patients with very few side effects in many clinical trials. The most commonly reported side effects were gastrointestinal symptoms, such as diarrhea.

6.Is soy approved by the U.S. Food and Drug Administration (FDA) for use to prevent or treat cancer in the United States?

The FDA 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. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of soy supplements may not be the same.

Current Clinical Trials

Vitamin D: Questions and Answers

1.What is vitamin D?

Vitamin D is a fat-soluble vitamin found in fatty fish, fish liver oil, and eggs. Vitamin D may also be added to dairy products.

Vitamin D has many functions in the body, such as the following:

A person’s vitamin D level is checked by measuring the amount of 25-hydroxyvitamin D in the blood.

2.How is vitamin D given or taken?

Vitamin D is made by the body when exposed to sunlight. Vitamin D may also be eaten in food or taken in dietary supplements.

3.Have any laboratory or animal studies been done using vitamin D?

For information on laboratory and animal studies done using vitamin D, see the Laboratory/Animal/Preclinical Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

4.Have any studies of vitamin D been done in people?

Population studies and clinical trials have been done to study the effects of vitamin D on prostate cancer. The results of these studies have been mixed. Some studies have shown a link between Vitamin D levels and prostate cancer, and others have not. There is not enough evidence to know whether vitamin D can prevent prostate cancer.

Combined studies

Population studies

Vitamin D levels were checked every year for 5 years in men with prostate cancer that had not spread. Throughout the study, low levels of vitamin D were found in these men.
Another study in men with prostate cancer suggested that medium or high levels of vitamin D in the blood may be linked with better outcomes than lower levels.
One thousand men with prostate cancer and 1,000 men who did not have prostate cancer were followed for up to 20 years in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Results suggested that men with higher blood levels of vitamin D had a greater risk of prostate cancer than men with lower vitamin D levels.
In an analysis from the Selenium and Vitamin E Cancer Prevention Trial (SELECT), men who had moderate blood levels of 25-hydroxyvitamin D were found to have a lower risk of aggressive prostate cancer than men who had either lower or higher levels of 25-hydroxyvitamin D.
A study of patterns of deaths in the United States from 1950 to 1994 showed that higher death rates from prostate cancer occurred in parts of the country with lower levels of UV radiation from sunlight.

Clinical trials

In a 2018 randomized controlled trial, vitamin D3 and omega-3 fatty acid supplements were given to prevent cancer and cardiovascular disease. Those who took the vitamin D supplement did not have a lower rate of any cancer.
A clinical trial treated patients with prostate cancer that had recurred (come back) with calcitriol (the active form of vitamin D) and naproxen for 1 year. Results showed that after taking calcitriol and naproxen the prostate-specific antigen (PSA) level rose more slowly.
In a 2010 study, patients with prostate cancer that did not respond to hormone therapy were treated with calcitriol and dexamethasone. The results showed no effect on PSA levels.
In a 2009 study, patients with locally advanced or metastatic prostate cancer were treated with vitamin D. The study reported that 1 in every 5 patients who took vitamin D had lower PSA levels.

5.Have any side effects or risks been reported from vitamin D?

Vitamin D can cause serious health problems when taken at high doses over many years. Taking high levels of Vitamin D can cause too much calcium to be absorbed in the intestines, leading to rapid increases in blood calcium levels. This condition is called hypercalcemia.

In a group of 26 studies, Vitamin D was reviewed for safety, how well it works, and whether it interacts with drugs used to treat prostate cancer and other tumors. The reviewers found the risk of side effects and interactions with other drugs to be low.

Several studies looked at the safety of high-dose vitamin D and how well it works with chemotherapy (docetaxel) to treat men with prostate cancer that did not respond to hormone therapy. The side effects that occurred after treatment with high-dose vitamin D and docetaxel were the same as the side effects noted after treatment with docetaxel alone.

6.Is vitamin D approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

The FDA has not approved the use of vitamin D as a treatment for cancer.

Vitamin D is available in the United States in food products and dietary supplements. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of vitamin D supplements may not be the same.

Current Clinical Trials

Vitamin E: Questions and Answers

1.What is vitamin E?

Vitamin E is an antioxidant that may help protect cells from damage. Vitamin E also affects how signals are sent within cells and how the cell makes RNA and proteins.

There are eight forms of vitamin E: four tocopherols (alpha-, beta-, gamma-, and sigma-) and four tocotrienols (alpha-, beta-, gamma-, and sigma-). Alpha-tocopherol, the form of vitamin E used in dietary supplements, is found in greater amounts in the body and is the most active form of vitamin E. Most vitamin E in the diet comes from gamma-tocopherol. Food sources of vitamin E include vegetable oils, nuts, and egg yolks.

Vitamin E may protect against chronic diseases, such as heart and blood vessel disease.

2.How is vitamin E given or taken?

Vitamin E may be eaten in food or taken in dietary supplements.

3.Have any studies of vitamin E been done in people?

Population studies and clinical trials have been done to find out if vitamin E may prevent prostate cancer. The results of these studies have been mixed; some studies have shown no change in the overall risk of prostate cancer, and others have shown an increased risk of prostate cancer. There is not enough evidence to know whether vitamin E affects the risk of prostate cancer.

Combined population studies

Population studies

The National Institutes of Health–American Association of Retired Persons (NIH-AARP) Diet and Healthy Study studied whether taking increased amounts of vitamin E in the diet and in dietary supplements could prevent prostate cancer. After 5 years, no link between vitamin E supplements and prostate cancer risk was found. However, a lower risk of advanced prostate cancer was found in men who took high amounts of gamma-tocopherol.
In a 2010 study that measured blood levels of vitamin E, the men who had prostate cancer had lower blood levels of vitamin E than those who did not have prostate cancer. In addition, those who had higher PSA levels had lower levels of vitamin E in their blood.
The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study (ATBC) trial measured blood levels of alpha-tocopherol and dietary intake of vitamin E in men who were followed for up to 19 years. Results showed no link between vitamin E in the diet and prostate cancer risk. However, higher levels of alpha-tocopherol in the blood may be linked with a lower risk of advanced prostate cancer.
Men in the ATBC trial who developed prostate cancer were studied to find out if blood levels of alpha-tocopherol affected survival time. Higher blood levels of alpha-tocopherol, at both time of diagnosis and at the 3-year time point, were linked with improved prostate cancer survival.

The Selenium and Vitamin E Cancer Prevention Trial (SELECT)

SELECT results published in 2011 showed that men taking vitamin E alone had a 17% increase in prostate cancer risk compared with men who did not take vitamin E.

Several factors may have affected study results, including the dose of vitamin E.

Clinical trials

4.Have any side effects or risks been reported from vitamin E?

In the Physicians’ Health Study II and the Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group, there was a higher number of strokes caused by a broken blood vessel in the brain in men who took vitamin E than in men who took a placebo.

5.Is vitamin E approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

The FDA has not approved the use of vitamin E as a treatment for cancer.

Alpha-tocopherols are deemed Generally Recognized as Safe by the FDA.

Vitamin E is available in the United States in food products and dietary supplements. The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of vitamin E supplements may not be the same.

Current Clinical Trials

Combination Therapies

Pomi-T (Pomegranate, Green Tea, Broccoli, and Turmeric)

Polyphenols are found in many plants and give some flowers, fruits, and vegetables their color. Polyphenols have antioxidant activity that may help protect cells from damage.

A food supplement that is high in polyphenols was studied in a group of men who had prostate cancer that had not spread. This supplement contained the following:

One hundred and ninety-nine men were randomly assigned to receive either the food supplement or a placebo for 6 months. The food supplement was well tolerated. However, men in the supplement group were more likely to have gastrointestinal symptoms, such as increased gas and loose bowels.

Lycopene, Selenium, and Green Tea

A dietary supplement was studied in 60 men at high risk of prostate cancer (high-grade prostatic intraepithelial neoplasia). The supplement contained the following:

The men were randomly assigned to receive the supplement or a placebo. Men who took the supplement for 6 months had higher rates of prostate cancer when they had a repeat biopsy than men who did not take the supplement. This result may be due to cancers missed at the start of the study.

Lycopene and Other Therapies

A study enrolled 79 men who were scheduled to have a prostatectomy. For 3 weeks before surgery, the men were assigned to eat or drink either:

The prostate-specific antigen (PSA) levels were the same for men who received added nutrients and those who did not. However, among men with intermediate-risk prostate cancer, lower PSA levels were found in those who ate the tomato products or had the highest increases in lycopene levels.

Zyflamend

Zyflamend is a dietary supplement that contains extracts of 10 different herbs in olive oil:

The herb extracts used in Zyflamend may have anti-inflammatory activity. There is not enough evidence to know whether Zyflamend can prevent or treat prostate cancer.

Zyflamend is taken as a dietary supplement in capsule form.

No serious side effects have been reported for Zyflamend. In one study, some men had mild heartburn that went away when Zyflamend was taken with food.

Other Prostate Health Supplements

Overview

African Cherry (pygeum africanum) and beta-sitosterol are two supplements that have been studied for general prostate health and the treatment of benign prostatic hyperplasia (BPH) and prostate cancer. For more information about African Cherry (pygeum africanum) and beta-sitosterol, see the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

About This PDQ Summary

About PDQ

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. 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 come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

Purpose of This Summary

Reviewers and Updates

The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board.

Clinical Trial Information

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.

Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).

Permission to Use This Summary

PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary].”

The best way to cite this PDQ summary is:

PDQ® Integrative, Alternative, and Complementary Therapies Editorial Board. PDQ Prostate Cancer, Nutrition, and Dietary Supplements. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/about-cancer/treatment/cam/patient/prostate-supplements-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389501]

Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 3,000 scientific images.

Disclaimer

The information in these summaries should not be used to make decisions about insurance reimbursement. More information on insurance coverage is available on Cancer.gov on the Managing Cancer Care page.

Contact Us

More information about contacting us or receiving help with the Cancer.gov website can be found on our Contact Us for Help page. Questions can also be submitted to Cancer.gov through the website’s E-mail Us.

General CAM Information

Complementary and alternative medicine (CAM)—also called 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 type of treatment. Some complementary and alternative therapies may affect their standard treatment or may be harmful when used with conventional treatment.

Evaluation of CAM Therapies

It is important that the same scientific methods used to test conventional therapies are used to test CAM therapies. The National Cancer Institute and the National Center for Complementary and Integrative Health (NCCIH) are sponsoring a number of clinical trials (research studies) at medical centers to test CAM therapies for use in cancer.

Conventional approaches to cancer treatment have generally been studied for safety and effectiveness through a 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 been tested using demanding scientific methods. A small number of CAM therapies that were thought to be purely alternative approaches are now being used 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) meeting in November 1997, acupuncture has been found to help control nausea and vomiting caused by chemotherapy and pain related to surgery. However, some approaches, such as the use of laetrile, have been studied and found not to work and to possibly cause harm.

The NCI Best Case Series Program which was started in 1991, is one way CAM approaches that are being used in practice are being studied. 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 carefully reviews these materials to see if any seem worth further 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:

To Learn More About CAM

National Center for Complementary and Integrative Health (NCCIH)

The National Center for Complementary and Integrative Health (NCCIH) 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.

CAM on PubMed

NCCIH 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 websites 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.)

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 website.

National Cancer Institute (NCI) Cancer Information Service

U.S. residents may call the Cancer Information Service (CIS), NCI's contact center, toll free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 9:00 am to 9:00 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.

Federal Trade Commission

The Federal Trade Commission (FTC) enforces consumer protection laws. Publications available from the FTC include:

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Current Clinical Trials

Current Clinical Trials

Current Clinical Trials

Current Clinical Trials

Current Clinical Trials

Current Clinical Trials

Current Clinical Trials

Current Clinical Trials

Current Clinical Trials

Pomi-T (Pomegranate, Green Tea, Broccoli, and Turmeric)

Lycopene, Selenium, and Green Tea

Lycopene and Other Therapies

Zyflamend

Overview

About PDQ

Purpose of This Summary

Reviewers and Updates

Clinical Trial Information

Permission to Use This Summary

Disclaimer

Contact Us