Modified Citrus Pectin
Other common name(s): citrus pectin, Pecta-Sol®, MCP
Scientific/medical name(s): none
Modified citrus pectin (MCP) is a form of pectin that has been altered so that it can be more easily absorbed by the digestive tract. Pectin is a carbohydrate that is made of hundreds or thousands of sugar molecules chemically linked together. It is found in most plants and is particularly plentiful in the peels of apples, citrus fruits, and plums. In modified citrus pectin, the pectin has been chemically altered to break its molecules into smaller pieces. Pectin in its natural form cannot be absorbed by the body and is considered a type of soluble dietary fiber, whereas modified pectin can be absorbed into the bloodstream.
Animal studies and a couple of uncontrolled human studies have found that MCP may inhibit the spread of prostate cancer and melanoma to other organs. However, there have been no controlled clinical studies to prove this effect in humans.
How is it promoted for use?
Proponents claim that modified citrus pectin slows or stops the growth of melanoma, a dangerous form of skin cancer, and metastatic prostate cancer (prostate cancer that has spread). Some also claim that a compound found in MCP strengthens the cancer cell–killing ability of T-cells, cells that also protect against germs.
What does it involve?
Modified citrus pectin is available as a capsule or a powder. The dose suggested by manufacturers for the powder is 5 grams (nearly a fifth of an ounce) mixed with water or juice taken 3 times a day with meals. For capsules, the suggested dose is 800 milligrams (mg) 3 times a day with meals.
What is the history behind it?
Pectin is commonly used as a gelling agent for canning foods and making jellies. It is also used widely in the production of food and cosmetics and as an ingredient in some anti-diarrhea medicines. In the past 10 years, the modified form of pectin has been investigated for anti-cancer properties.
What is the evidence?
Several animal studies found that MCP helped reduce the spread of prostate, breast, and skin cancer. Animals with these types of cancer that were fed MCP had a much lower risk of the tumor spreading to the lungs. For example, one study examined the effects of MCP on lung metastases from melanoma cells. Researchers injected mice with melanoma cells. In the mice that were also given MCP, significantly fewer tumors spread to the lungs than in the mice that did not receive the drug. When lung tumors did develop in the mice treated with MCP, the tumors tended to be smaller than those that formed in untreated animals.
These studies appear to show that MCP makes it difficult for cancer cells that break off from the main tumor to join together and grow in other organs. However, in most animal studies, MCP had no effect on the main tumor, suggesting that it may only be useful for preventing or slowing the growth of metastatic tumors in very early stages of development.
Recent laboratory studies of human and animal cells have provided information on how MCP might slow the spread of cancer. MCP appears to attach to galectin-3, a common chemical in many cells. Galectin-3 is present in abnormally high levels in many cancers and plays an important role in the growth, survival, and spread of cancer cells.
Although animal and cell studies are quite encouraging, very little information is available about whether MCP is effective in humans. In one published clinical trial, 10 men with prostate cancer were treated with MCP after standard treatment failed. In 7 of these men, blood tests found prostate-specific antigen (PSA, a marker of prostate cancer growth). Their PSA doubling time (a measure of how fast PSA goes up) improved in comparison with measurements done before taking MCP, indicating that MCP may have a slowing effect on the cancer's growth. This study had no control group (in this case, a group of men who did not take MCP), which limits the strength of its conclusions on MCP's effectiveness. It also did not measure survival or other important endpoints. However, taken with the information gained from animal studies, it suggests that MCP may have a role in reducing the growth and spread of cancer. Randomized controlled trials looking at larger groups of people must be done before any firmer conclusions can be reached.
Are there any possible problems or complications?
Citrus pectin is categorized as "generally regarded as safe" by the U.S. Food and Drug Administration, When MCP is used as intended, side effects rarely occur. However, some people may experience stomach discomfort after taking MCP. There have been a few case reports in which asthma developed in people after exposure to powdered pectin. Modified citrus pectin may cause serious allergic reactions in those who are allergic to citrus fruits.
Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.
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).
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: 11/01/2008