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Cassava

Other common name(s): cassava plant, tapioca, tapioca plant, manioc

Scientific/medical name(s): Manihot esculenta Crantz

Description

The cassava plant is a staple crop in Africa, Asia, and South America. Tapioca is a starch found in the roots (tubers) of the plant. Different parts of the plant such as the root, leaves, and sometimes the whole plant, are used in herbal remedies.

Overview

There is no convincing scientific evidence that cassava or tapioca is effective in preventing or treating cancer. However, some researchers have proposed an idea that might eventually lead to treatments that use an enzyme from the cassava plant. This approach has not been scientifically tested.

How is it promoted for use?

In folk medicine, the cassava plant is promoted for treating snakebites, boils, diarrhea, flu, hernia, inflammation, conjunctivitis, sores, and several other problems including cancer.

Cassava plants can produce the poisonous substance cyanide as a way to fend off animals trying to eat them. Chewing the plant causes it to release an enzyme called linamarase, and linamarase, in turn, converts a compound in the plant called linamarin into cyanide. Researchers have suggested that this ability might be useful as a form of gene therapy. First, the gene for linamarase could be selectively put into cancer cells. If linamarin were then introduced into the body, cancer cells would break it down and release cyanide only in the area around the cancer cells, killing them. Since normal cells would not have the linamarase gene and would not be able to convert linamarin into cyanide, they would not be affected.

What does it involve?

In herbal remedies, the roots of the cassava are made into a poultice and applied directly to the skin as a treatment for sores. The leaf, root, and flour obtained from the plant can also be used in a wash that is applied to the skin. In developing countries, tapioca starch made from the cassava plant is used to help restore body fluids.

Cassava leaves are sold in health food stores and on the Internet in capsule or powder form. Cassava root starch may be used in Vitamin C supplements.

The parts of cassava used for food are the tubers, which are usually eaten raw, boiled, or fried. A form of flour is also made from the cassava plant. In Western countries, tapioca is found in baby foods and prepared as a dessert.

What is the history behind it?

Cassava has been used as a food source by many cultures for centuries. Today, it is consumed by millions of people in developing countries and is sometimes used as an herbal medicine. It has been theorized that the plant's ability to make cyanide may be useful as a type of gene therapy to treat cancer, but further research is needed to determine whether the technique will work in humans. This use would be quite different from the use of the cassava plant as an herbal remedy.

What is the evidence?

Available scientific evidence does not support claims that botanical products currently made from the cassava plant have anticancer properties. A British researcher identified the cassava genes involved in making hydrogen cyanide in the early 1990s. In collaboration with cancer specialists in Spain, she has conducted studies of the linamarase gene. They added this gene to a virus, which was then injected into rat brain tumors. These tumors were killed when the rats were infused with linamarin. Further research is needed to determine if this technique will work in people.

Many scientists around the world are currently developing gene therapy methods for introducing DNA selectively into the tumor cells of cancer patients. More research is needed to determine whether linamarin and linamarase can be safely and effectively used to kill cancer cells in people with cancer.

Extracted chemicals or substances are different from the raw plant. Study results of extracts are not expected to have the same result as studies using the raw plant.

Are there any possible problems or complications?

The cassava plant produces cyanide, a poison that can be deadly to humans, and cassava can be a serious health hazard if it is not processed properly. Some of the signs of cyanide poisoning are headache, dizziness, agitation, confusion, coma, and convulsions. Some people in developing countries have been poisoned by eating parts of the cassava plant that were not prepared properly.

In regions of Africa and Latin America where cassava is a main staple food, illnesses due to consuming smaller amounts of cyanide taken in over a long period of time can occur if cassava leaves or roots are not processed properly. Effects can include paralysis of the legs, trouble walking, and poor vision and hearing. Malnutrition can also occur when cassava is a major part of the diet because of the plant is low in protein and certain micronutrients.

Some people are allergic to cassava. Those with allergies to natural rubber latex may be more likely to have serious reactions. 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).

Dietary Supplements: What Is Safe?

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

Complementary and Alternative Methods and Cancer

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer

References

Cardoso AP, Mirione E, Ernesto M, et al. Processing of cassava roots to remove cyanogens. Journal of Food Composition and Analysis. 2005; 18:451–460.

Cortes ML, Garcia-Escudero V, Hughes M, Izquierdo M. Cyanide bystander effect of the linamarase/linamarin killer-suicide gene therapy system. J Gene Med. 2002;4:407-414.

Gaspar A, Neto-Braga C, Pires G, et al. Anaphylactic reaction to manioc: cross-reactivity to latex. Allergy. 2003;58:683-4.

Hughes J, Keresztessy Z, Brown K, Suhandono S, Hughes MA. Genomic organization and structure of alpha-hydroxynitrile lyase in cassava (Manihot esculenta Crantz). Arch Biochem Biophys. 1998;356:107-116.

Purdue University Center for New Crops & Plants Products Web site. Manihot esculenta Crantz. Accessed at: www.hort.purdue.edu/newcrop/duke_energy/Manihot_esculenta.html on June 10, 2008.

Teles FF. Chronic poisoning by hydrogen cyanide in cassava and its prevention in Africa and Latin America. Food & Nutrition Bulletin.2002; 23:407-412.

Wapnir RA, Wingertzahn MA, Moyse J, Teichberg S. Proabsorptive effects of modified tapioca starch as an additive of oral rehydration solutions. J Pediatr Gastroenterol Nutr. 1998;27:17-22.

White WLB, Arias-Garzon DI, McMahon JM, Sayre RT. Cyanogenesis in cassava. The role of hydroxynitrile lyase in root cyanide production. Plant Physiol. 1998;116:1219-1225.

Wingertzahn MA, Teichberg S, Wapnir RA. Modified starch enhances absorption and accelerates recovery in experimental diarrhea in rats. Pediatr Res. 1999;45:397-402.

Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 11/01/2008
Last Revised: 11/01/2008