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Modified Citrus Pectin for Cancer? -- close up of an orange and orange peel


Modified citrus pectin (MCP) is a soluble fiber that has been processed in such a way that it can be absorbed - and as a supplement, has been promoted for "detoxification," "cellular health," and preventing or slowing cancer growth such as in prostate and breast cancer tumors.

Prostate Cancer:
In-vitro and animal studies suggest that MCP may slow the growth of certain cancer cells, including human prostate cancer cells (Yan, Integr Cancer Ther 2010; Glinsky, Carbohydr Res 2009; Nangia-Makker, J Natl Cancer Inst 2002). However, there have been only two clinical studies on the effects of MCP in men with prostate cancer and neither study included a control group or placebo, making the results questionable.

One small clinical trial of 10 men with prostate cancer who were given MCP after traditional treatments failed (radical prostatectomy, radiation or cryosurgery) found that a daily dose of 14.4 g (6 capsules containing 800 mg Pecta-Sol® taken three times per day) for 12 months significantly slowed the rate at which prostate antigen (PSA) levels increased in the blood (Guess, Prostate Cancer Prostatic Dis 2003). (There is a higher risk of death when PSA levels rise rapidly, such as doubling in just three months. A slower rise, such as a doubling over one to 10 years, is associated with local rather than systemic recurrence (Tollefson, Mayo Clin Proc 2007)).

A second clinical study in Germany found that among 29 men and women with various advanced solid cancerous tumors (including 10 men with prostate cancer tumors) who took 5 grams of MCP powder (mixed with water and juice three times per day) for two to four months, an overall clinical response associated with a stabilization and/or improvement in measures of quality of life, such as fatigue, pain, and appetite was reported. The study also included individuals with breast, colorectal, liver, pancreatic and cervical cancer (Azemar, Clin Med Insights Oncol 2007).

Breast Cancer:
Similarly, evidence that MCP may be beneficial for slowing breast cancer growth is very preliminary. The study above that found MCP improved certain measures of quality of life in men and women with various types of cancer included five patients with advanced solid breast cancer tumors, although results were reported for the whole group, not by specific types of cancer, and the study did not a control group or placebo, which is necessary to show that a treatment is effective (Azemar, Clin Med Insights Oncol 2007). The only other evidence appears to be a study in mice injected with human breast cancer cells found that MCP given orally slowed breast tumor growth (Nangia-Makker, J Natl Cancer Inst 2002).

The Susan G. Komen foundation for breast cancer notes "Modified citrus pectin is still considered an experimental therapy for cancer and should be used as an adjuvant to standard cancer therapy under medical supervision."

Side Effects:
Modified citrus pectin is generally well-tolerated, although mild gastric upset, gas and diarrhea have been reported. In a study among people with cancer, the most commonly reported side effects were itching, upset stomach and gas; one individual with liver cancer stopped supplementation due to increased itching (Azemar, Clin Med Insights Oncol 2007).

Pectasol® and PectaSol-C® are the commonly sold brands of modified citrus pectin powders which have been used in clinical studies, with similar recommended dosages as used in these studies — 5 grams three times per day. Capsules are available and may be more convenient to carry but generally contain 1 gram or less, so about 6 capsules per serving would be required.

The bottom line:
Preliminary evidence suggests modified citrus pectin may slow the growth of cancerous cells or improve quality of life measures in individuals with prostate or breast cancer, but use of MCP is still considered experimental. Larger, placebo-controlled studies are needed. It is general well-tolerated, although itching, upset stomach, gas, cramping and diarrhea have been reported. Look for supplements containing Pectasol® and PectaSol-C®, which have been used in clinical studies. (See our Where to Buy page for our list of retailers that sell modified citrus pectin that we've found to be reputable.)

For information on other supplements for prostate cancer, see the Green Tea Review, and for more about supplements that may treat non-cancerous prostate symptoms, see the Saw Palmetto Review.

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September 1, 2019

I have been taking modified citrus pectin daily since being diagnosed with a breast tumor. I declined conventional treatments and for 10 years the tumor has remained localized. I am very grateful that my oncologist told me about it ten years ago.
October 21, 2019

Thank you for sharing this Esther. As discussed in the answer above, the evidence for this use is very preliminary.

August 17, 2020

Which MCP brand do you use?

June 10, 2019

Hello, Eugenics Pectasol-C is labeled with warning:
"This product contains a chemical known to the State of California to cause cancer, birth defects, or..."
Do you know why? Is it safe?
June 10, 2019

Eugenics Pectasol-C may contain an amount of lead that exceeds the strict limit in California, above which a warning label is required. This is suggested by information on the website of that product. We have not tested this product, so, unfortunately, we don't know the actual amount of lead it contains.

November 14, 2016

A recent study reported in Nature found that ingestion of Modified citrus pectin significantly reduced insulin resistance and its effects.
November 14, 2016

Hi Nalani - Thanks for sharing that study. However, please be aware that it is based on an animal experiment, not a study in people. This has not yet been demonstrated in people.

MAX 155
September 10, 2014

According to LIFE EXTENSION, MCP is also effective in Congestive Heart Failure cases in that it stops the remodeling of the heart. This is a subject of the October 2014 issue.

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