Prostate Cancer, Nutrition, and Dietary Supplements (PDQ®): Integrative, alternative, and complementary therapies - Patient Information [NCI]

What is calcium?

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

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 bok choy, kale, and broccoli. Calcium is sometimes added to foods and drinks, such as fruit juices, tofu, and cereals.

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

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.

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 supplements, 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.

For information on studies in people taking calcium supplements, dairy products, or non-dairy calcium products, see the Human Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

Is calcium approved by the 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 regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of calcium supplements may not be the same.

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 suggest that green tea may protect against heart and blood vessel disease.

How is green tea given or taken?

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

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.

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.

Overall, population studies suggest that green tea may help protect against prostate cancer in Asian populations. Prostate cancer deaths in Asia are among the lowest in the world. Other populations have not been studied.

For information on studies in people drinking green tea or taking green tea supplements, see the Human Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

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 US cups) 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 of green tea included insomnia, confusion, and fatigue. In rare cases, liver problems have occurred.

Is green tea approved by the 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 regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of green tea supplements may not be the same.

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.

How is lycopene given or taken?

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

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.

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. Some studies have shown a lower risk of prostate cancer or a decrease in prostate-specific antigen (PSA) level, and others have not. These mixed results may be explained by differences within the studies, such as the sources and types of lycopene studied, the diets of the participants, and differences in participants' prostate cancer risk factors (e.g., genetics, obesity, and tobacco and alcohol use). Also, 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 is not enough evidence to know whether lycopene can prevent or treat prostate cancer.

For information on studies in people taking lycopene supplements or foods containing lycopene, see the Human Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

For information on trials of combination therapies that include lycopene, see the Combination Therapies section of this summary.

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.

Is lycopene approved by the 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 available in the United States in food products and dietary supplements. The FDA regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of lycopene supplements may not be the same.

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).

How is MCP given or taken?

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

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.

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.

Have any side effects or risks been reported from MCP?

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

Is MCP approved by the 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 regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of MCP supplements may not be the same.

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:

• The peel, which makes up half the fruit and contains polyphenols and minerals.
• The seeds.
• The aril (the layer between the peel and the seeds), which contains phenolics and flavonoids including anthocyanins, which give the pomegranate fruit and juice a red color.

How is pomegranate given or taken?

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

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.

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.

Have any side effects or risks been reported from pomegranate?

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

Is pomegranate approved by the 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 regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of pomegranate supplements may not be the same.

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.

How is selenium given or taken?

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

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.

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.

For information on studies in people taking selenium, see the Human Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

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

Selenium supplements have been well tolerated in many clinical trials. But, in the Selenium and Vitamin E Cancer Prevention 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.

Is selenium approved by the 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 regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of selenium supplements may not be the same.

What is soy?

The soybean plant has been grown in Asia for food for hundreds of years. Soybeans are used to make soy milk, miso, tofu, soy flour, oil, and other food products.

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.

How is soy given or taken?

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

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.

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.

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 Prostate Cancer, Nutrition, and Dietary Supplements for information on randomized, placebo-controlled clinical trials of isoflavones and soy.

For more information on studies in people taking soy supplements, soy products, or soy found in foods, see the Human Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

Have any side effects or risks been reported from soy?

Soy products and isoflavones have caused very few side effects in people with prostate cancer who participated in clinical trials. The most commonly reported side effects were gastrointestinal symptoms, such as diarrhea.

Is soy approved by the 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 regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of soy supplements may not be the same.

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:

• Helps absorb calcium from food in the small intestine.
• Improves muscle strength and immune system function.
• Lowers inflammation.
• Maintains levels of calcium and phosphate in the blood.
• Helps with bone growth and protects against osteoporosis in adults.

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

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.

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.

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.

Studies often look at specific factors that affect a person's vitamin D levels to see how those factors influence prostate cancer risk. Factors that have been studied include:

• Low sun exposure.
• Levels of vitamin D in the diet and blood.
• Genetic changes.

Some genetic changes in tumor features that interact with vitamin D might affect the growth and spread of prostate cancer. One of those features is a molecule called a vitamin D receptor. Studies suggest that changes in this receptor could influence a person's risk of prostate cancer or increase the chance that the cancer will spread. More research is needed to confirm that vitamin D receptors play a role in prostate cancer.

For information on studies in people taking vitamin D supplements, vitamin D products, or vitamin D in food, see the Human Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

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.

Is vitamin D approved by the 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 regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of vitamin D supplements may not be the same.

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.

How is vitamin E given or taken?

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

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.

For information on studies in people taking vitamin E supplements, vitamin E products, or vitamin E in food, see the Human Studies section of the health professional version of Prostate Cancer, Nutrition, and Dietary Supplements.

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.

Is vitamin E approved by the 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.

Vitamin E is available in the United States in food products and dietary supplements. The FDA regulates dietary supplements separately from foods, cosmetics, and drugs. The FDA's Good Manufacturing Practices require that every finished batch of supplements is safe and that the claims on the label are true and do not mislead the consumer. However, the FDA does not regularly review the way that supplements are made, so all batches and brands of vitamin E supplements may not be the same.