White Birch

Other common name(s): white birch, silver birch; compounds made from the bark include butalin and betulinic acid, also called bet a

Scientific/medical name(s): Betula pendula, Betula alba

Description

White birch is a tree that grows in northern Europe and North America. The bark, leaves, and buds from this and related birch trees are used in herbal and folk medicines. One of the chemicals that has been isolated from birch bark is called betulin. Betulinic acid, which is made from betulin, is being studied as a possible cancer treatment. Betulin has also been found in many other plants.

Overview

Birch bark, buds, and leaves are used in folk medicine but have not been studied to find out whether they are safe or effective. However, betulinic acid may hold promise as an anticancer agent. Some laboratory and animal studies of betulinic acid have reported antitumor activity. Additional studies are under way to find out whether it has a role in treating several forms of cancer, including melanoma and certain brain cancers. Clinical trials are needed to determine what effect, if any, betulinic acid may have in treating cancer in humans.

How is it promoted for use?

Birch bark or white birch (which contains betulinic acid and other compounds) is used on the skin to treat warts, eczema, and other skin conditions. Promoters say that birch tea can be taken internally as a diuretic or a mild sedative and that it can be used as a treatment for rheumatism, gout, and kidney stones. The leaves are sometimes used on the scalp to help with hair loss and dandruff. Birch tar (an oil distilled from birch bark) is used on the skin for skin irritations and parasites. Other claims for birch bark include the treatment of diarrhea, dysentery, and cholera.

Some researchers believe that betulin, which can be extracted from birch bark and other sources, causes some types of tumor cells to start a process of self-destruction called apoptosis. They also believe that betulinic acid slows the growth of several types of tumor cells and the human immunodeficiency virus (HIV). Some researchers also think it has antibacterial properties.

What does it involve?

Pure betulinic acid is not directly available for public use, but birch bark flakes, powder, capsules, oil, sap, and liquid extracts are sold in herbal medicine shops and on the Internet. Birch bark, buds, or leaves are used internally or externally. Tea can be made by steeping a teaspoon of the birch bark in a cup of boiling water for 15 minutes. Proponents recommend drinking from 2to 5 cups of tea per day. Birch leaves or powder can also be used to make tea. For skin conditions, birch leaf tea may be used as a wash or added to bath water. Birch bark or leaves can be applied directly to the skin as well. Birch oil is sometimes used in ointments or liniments and is considered a substitute for wintergreen. Some people also drink small amounts of fresh or bottled birch sap as a tonic.

What is the history behind it?

White birch bark has been used by Native Americans as a folk remedy for some time. It was used in tea and other beverages to treat stomach and intestinal problems such as diarrhea and dysentery. In Russia, it has been used since 1834. In Europe, birch sap was fermented into beer, wine, and other spirits. Its inner bark was sometimes eaten as food.

In 1994, scientists at the University of North Carolina reported that chemicals found in white birch bark slowed the growth of HIV. The following year, a researcher at the University of Illinois reported that betulinic acid killed melanoma cells in mice. Since then, a number of researchers have conducted laboratory tests on betulinic acid to determine its antitumor properties. Since that time, betulin has been found in several other plant sources.

What is the evidence?

There has not been enough scientific study of white birch in humans to draw conclusions about its usefulness in treating illness, although some birch extracts have been studied for safety. Xylitol, a type of sugar, can be made from birch and has been approved to flavor food. Several other compounds extracted from birch have also been approved by the US Food and Drug Administration (FDA) for use as food additives.

Betulinic acid has not been studied in humans, but several laboratory studies have looked at its effects when it is added to cancer cells growing in laboratory dishes. These studies, using the pure chemical betulinic acid rather than birch bark, have been published in peer-reviewed medical journals and suggest that betulinic acid holds some promise for patients with melanoma, certain nervous system tumors, and other forms of cancer. Three German studies concluded that betulinic acid showed anti-tumor activity against cells from certain types of nervous system cancers in children. Two laboratory studies conducted at the University of Illinois indicated that betulinic acid may prove useful as an antitumor drug.

Several studies have found that betulinic acid increases sensitivity of cancer cells in laboratory dishes or in rodents to chemotherapy drugs such as vincristine, 5-fluorouracil, irinotecan, and oxaliplatin. Some researchers are testing synthetic chemicals related to betulinic acid to determine which are the strongest in killing cancer cells or preventing their growth. Studies are still going on to find out whether these results can be applied to humans.

Results from a German nonrandomized clinical trial published in 2006 indicated that birch bark extract may be an effective treatment for actinic keratosis, a pre-cancerous skin condition. However, birch bark extract cannot be recommended for actinic keratoses until further studies have compared it with conventional treatments already known to be safe and effective.

Are there any possible problems or complications?

This product is sold as a dietary supplement in the United States. Unlike companies that produce drugs (which must provide the FDA with results of detailed testing showing their product is safe and effective before the drug is approved for sale), the companies that make supplements do not have to show evidence of safety or health benefits to the FDA before selling their products. Supplement products without any reliable scientific evidence of health benefits may still be sold as long as the companies selling them do not claim the supplements can prevent, treat, or cure any specific disease. Some such products may not contain the amount of the herb or substance that is written on the label, and some may include other substances (contaminants). Though the FDA has written new rules to improve the quality of manufacturing processes for dietary supplements and the accurate listing of supplement ingredients, these rules do not take full effect until 2010. And, the new rules do not address the safety of supplement ingredients or their effects on health when proper manufacturing techniques are used.
Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Birch products that are sold as supplements have not been studied for safety. However, people who are sensitive to aspirin should not use birch products, because birch contains large amounts of aspirin-like compounds. Birch may also pose a hazard to people with poor heart or kidney function. The full range of effects is not well known. Pregnant women, breastfeeding women, and children should not use birch products. Birch has been reported to cause skin rashes and, like most plants, may cause allergic reactions.

Researchers are still studying betulinic acid. Further testing is needed to find out whether it is safe for humans.

Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

Additional resources

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).

Guidelines for Using Complementary and Alternative Therapies

Dietary Supplements: How to Know What Is Safe

The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

Complementary and Alternative Methods for Cancer Management

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer