What can you do with leftover lemon peel? According to one food blog, you can use it to “whip up a mouthwatering seasoning, flavoring extract, luster-boosting furniture polish or all-purpose cleaner!” What if you could also use a component of lemon peel called pectin to cure prostate cancer? Sound crazy? Well, a multicenter study out of Israel has completed Phase II of a study using modified citrus pectin to control biochemically recurrent, nonmetastatic prostate cancer (PCa)—and it the results were promising.

What is modified citrus pectin?

Pectin is a naturally occurring substance found in the spongy pulp of citrus peels from lemons, limes, grapefruit and oranges. Since pectin is not absorbed by our intestines, it must be processed into a modified form that can be get into the bloodstream via the digestive system. This modified form is sold as a supplement most commonly branded as PectaSol (there are also other brands). It is marketed as “super-nutrient” supplement.

Is it as super as it is claimed to be? Well, if you can believe the claims, it is a relatively inexpensive multipurpose product. According to PectaSol promotional materials, benefits include healthy aging, cardiovascular support, detoxification, optimum cell function, and more. Among other things, it biologically inhibits a molecule called galectin-3, which plays an important role in cell health, programmed cell death, inflammation, certain tissue building blocks, and even the immune system. However, because it is a binding lectin, too much of it is a warning sign such disease conditions as cardiac fibrosis, which means thickening or scarring of heart tissue. Such thickening is due to a “sticky” quality of galectin-3, a characteristic that cancer cells readily turn to their own advantage.

You see, as a binding substance, think of galectin-3 has having adhesive properties. Circulating cancer cells can capitalize on galectin-3 to stick to the walls of blood vessels; from there, they can penetrate through to implant in organ or other tissues. Then, galectin-3 helps the new cell colony to clump up and form a tumor (pathogenesis). Also, too much galectin has the effect of reducing programmed cell death, in turn contributing to cancer cells not dying off naturally and therefore proliferating.

Can modified citrus pectin counteract galectin-3 activity?

According to the Israeli study I mentioned earlier, modified citrus pectin “… is a competitive inhibitor of the galectin-3 protein, which is involved in cancer pathogenesis.”^[i] This means it discourages or counteracts the formation of metastatic cancer tumors. The Phase II study involved 39 PCa patients who had previously been involved in a 6-month Phase I study of PectaSol modified citrus pectin (P-MCP) for suspected biochemical recurrence (based on rising PSA following whole gland treatment). During those first 6 months, their PSA doubling time (PSA-DT) slowed down, and at the end of the study period they have no evidence of disease progression or side effects severe enough to limit P-MCP dose.

Now, continuing on into Phase II meant an additional 12 months of taking 4.8 g of P-MCP by mouth 3 times per day, for a total of 39 months.

During the study period, patients had monthly PSA blood draws and visits for physical exams to check for side effects. For the 39 patients who completed all 18 months of the study, they were given PSMA PET scans at 6 and 18 months. The authors write,

The primary efficacy endpoint was the rate of patients without PSA progression (defined as an increase of ≥25% from baseline) and/or patients with improvement (lengthening) of PSADT versus baseline. The post-baseline PSADT was calculated using baseline PSA measurements obtained at the start of the study and every month during treatment. Secondary endpoints included the rate of patients without radiologic progression and toxicity, and with treatment benefits according to the PSADT risk grouping (e.g., poor < 3 months, intermediate 3–8.99 months, and good ≥9 months).^[ii]

Results were as follows:

• Decreased or stable PSA – 33 patients (85%)
• And/or improvement of PSA doubling time – 21 patients (54%)
• Negative PSMA-PET scans – 35 patients (90%).
• The average PSA doubling time improved from a pre-supplement 10.3 months to a post supplement 43.5 months.

The authors concluded that their total 18 months study showed that P-MCP may offer a sustained benefits and is safe for patients with biochemically recurrent PCa and no evidence of metastasis.

For those who follow our blogs, you know that we encourage lifestyle changes (diet, exercise, stress management) that have demonstrated value in preventing PCa. We occasionally post news about research on particular supplements. However, we do not recommend experimenting with your health by taking MCP or any other product without first consulting with your doctor. A single published study is a report of statistics, not medical advice. As promising as MCP may sound, don’t rush to start taking this supplement. Please join us in reserving judgment until larger, randomized, controlled research studies are done. When it comes to new supplement use, better safe than sorry.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

[i] Keizman D, Frenkel M, Peer A, Rosenbaum E et al. Modified Citrus Pectin Treatment in Non-Metastatic Biochemically Relapsed Prostate Cancer: Long-Term Results of a Prospective Phase II Study. Nutrients. 2023 Aug 11;15(16):3533.
[ii] Ibid.