Other common name(s): Carticin, Cartilade™, BeneFin™, Neovastat (AE-941)
Scientific/medical name(s): none
Shark cartilage comes from the skeletons of sharks. Cartilage is a type of smooth, flexible connective tissue that is found in the skeletal systems of many animals, including humans. Unlike mammals, birds, reptiles, amphibians, and most other fish, sharks have skeletons made up entirely of cartilage instead of mostly bones, with smaller amounts of cartilage.
Because of variations in the way it is harvested and processed, shark cartilage products can be very different, ranging from powdered preparations to homogenized liquid. The major compounds in shark cartilage are proteoglycans and glycoproteins (large molecules with protein and carbohydrate components), as well as protein and calcium salts. Shark cartilage is promoted mainly as an alternative to conventional cancer treatment, but some forms have been studied for use along with standard treatments.
Available scientific evidence does not support claims that shark cartilage products sold as dietary supplements are an effective treatment for cancer, osteoporosis, or any other disease. One shark cartilage product, called AE-941, was studied as an investigational new drug.
Although some laboratory and animal studies have shown that some components in shark cartilage have the ability to slow the growth of new blood vessels, these effects have not been proven in humans. The clinical studies of shark cartilage products published to date have not proven any benefit against cancer.
How is it promoted for use?
Supporters believe that supplements made from shark cartilage or cartilage from other animals, such as cows (see also Bovine Cartilage), can slow or stop the growth of cancer. According to its supporters, shark cartilage contains proteins that stop angiogenesis, the process of blood vessel development. Tumors need a network of blood vessels to survive and grow, so cutting off a tumor's blood supply starves it of nutrients, causing it to shrink or disappear. Some supporters also claim that shark cartilage can help against other diseases such as osteoporosis, arthritis, psoriasis, macular degeneration, and inflammation of the intestinal tract.
What does it involve?
Shark cartilage is usually taken by mouth as a capsule, powder, or liquid extract, but some people have trouble taking it by mouth because of the strong fishy smell and taste. In clinical trials, it has sometimes been given as an enema or injected under the skin. The dose and length of treatment varies widely. Manufacturers often recommend large doses (up to 1 cup a day). Chondroitin, a supplement often used with glucosamine to help arthritis, is also made from cartilage. Either bovine or shark cartilage may be used to produce chondroitin.
Shark cartilage dietary supplements are different from AE-941, a liquid shark extract known as Neovastat. This extract is regulated by the U. S. Food and Drug Administration (FDA) as an investigational new drug, and has been studied in clinical trials in people with cancer.
What is the history behind it?
A New York surgeon named John Prudden began investigating the use of animal cartilage as a medical treatment in the early 1950s. He used powdered cow cartilage to help heal the wounds of surgical patients and later used it to treat cancer. He reported that tumors shrank in more than half of the patients he treated, but the results have not been repeated in other studies.
Since then, many kinds of cartilage, from animals such as pigs, sheep, chickens, cows, and sharks, have been studied. After the 1992 publication of a popular book titled Sharks Don't Get Cancer, written by I. William Lane, PhD, shark cartilage supplements became very popular among people interested in alternative medicine. The idea was that cancer does not seem to develop in sharks as much as in humans, so there may be something in the sharks' systems that protects them from the disease.
Interest in shark cartilage increased after a television news magazine aired a segment in 1993 showing a study of patients with advanced cancer in Cuba who had gone into remission after being treated with shark cartilage. The results, however, have not been published in a peer-reviewed medical journal. The National Cancer Institute (NCI) later concluded that the results of the Cuban study were "incomplete and unimpressive."
According to the FDA and the Federal Trade Commission, some manufacturers of shark cartilage supplements have been fined and/or forced to remove their products from the market for making unproven claims that they have cancer-fighting abilities. Such claims can only be made for drugs with proven effects.
Finding drugs that halt the spread of cancer by stopping the growth of blood vessels has been the subject of many conventional research studies in recent years. This therapy, called anti-angiogenesis therapy, holds a great deal of promise for certain types of cancer. A number of anti-angiogenesis drugs are currently being studied, and one has been approved to treat certain types of cancer. In addition, several other drugs that were approved have anti-angiogenic effects. These are now being studied more carefully for their role in anti-angiogenesis. Despite the efforts to purify compounds in cartilage that stop the growth of blood vessels, the most promising anti-angiogenic substances now in existence are those that have been purified from sources other than cartilage or have been made in laboratories.
What is the evidence?
The consensus of available scientific evidence does not support claims that whole shark cartilage supplements are an effective treatment for cancer in humans. Although studies using cow and shark cartilage in people with cancer began in the early 1980s, few have been published. The scientific relevance of many of these studies is open to question because they do not describe how treatment was given, how patients were assessed, long-term survival outcomes, or information about the cartilage used and its components.
Some experiments have shown that some forms of shark cartilage possess a modest ability to slow the growth of new blood vessels in laboratory cell cultures and in animals, but the effects on humans are not so clear. According to one review, results from 9 clinical series of patients receiving shark cartilage were mixed. None of the series were done under strict scientific controls.
Researchers generally agree that the protein molecules in shark cartilage may be too large to be absorbed by the digestive tract and are simply excreted without ever reaching tumors in the body. However, some scientists have suggested that these substances may be more readily absorbed when taken in a liquid form. One study concluded that the liquid shark cartilage extract AE-941 (Neovastat) taken by mouth slowed the growth of new blood vessels in healthy men, suggesting to the study authors that the active ingredients in liquid shark cartilage were available for use by the body. By then, studies of the extract in people with cancer were also underway.
In one clinical trial involving about 50 patients, researchers concluded that shark cartilage supplements had no effect on patients with advanced-stage cancers. Later, a placebo-controlled clinical trial tested shark cartilage in more than 80 patients with advanced cancer, and found no benefit. "It wasn't well tolerated, there wasn't any suggestion of benefit in terms of quality of life, there wasn't any suggestion of benefit in terms of survival," commented Charles L. Loprinzi, the physician who authored the study report.
A small study of the AE-941 liquid extract first seemed to suggest that larger doses helped to prolong survival in patients with advanced kidney cancer, but patients were not randomized, and some people were switched from the low-dose to the high-dose group. Because of these design and methodology problems, no conclusions could be drawn from the study. A larger study was then done. Although the results of this study have not been published, the manufacturer stopped testing it against kidney cancer, suggesting that the results may not have been positive. More recently, the NCI sponsored a large, placebo-controlled randomized clinical trial using the extract with conventional chemotherapy and radiation therapy for the treatment of advanced (stage III) lung cancer. Results were published in 2010; based on analysis of outcomes from 379 patients, the researchers concluded that AE-941 did not improve overall survival.
Are there any possible problems or complications?
Shark cartilage is not thought to be toxic, although it has been known to cause nausea, indigestion, fatigue, fever, and dizziness in some people. Some people dropped out of the clinical trials because they couldn’t stand the taste. It may affect liver function, so ask your doctor before taking it if you have any kind of liver disease. It may also slow down the healing process for people recovering from surgery. People with a low white blood cell count should not take shark cartilage enemas, because there is a risk of life-threatening infection. Children should not take it because it could interfere with body growth and development.
Allergic reactions are possible. People with seafood allergies should avoid shark cartilage and chondroitin that is made from it. Women who are pregnant or breast-feeding should also avoid these supplements.
There is concern as of early 2012 that some shark fins have been found to contain variable amounts of an amino acid called BMAA (beta- methylamino-L-alanine). Supplements have not been analyzed yet to find out if they contain BMAA, but the amino acid is linked to neurologic (brain and nervous system) degeneration. Further study is needed to find out if this substance is present in the supplements.
It is not known whether shark cartilage could cause any problems from interactions with other medicines. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer, may have serious health consequences.
To learn more
More information from your American Cancer Society
Here is more information you might find helpful. You also can order free copies of our documents from our toll-free number, 1-800-227-2345, or read them on our Web site, www.cancer.org.
The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management
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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 Revised: 12/07/2012