Modified Citrus Pectin & Cancer: How a Simple Citrus Fiber May Influence Cancer Biology

Understanding what Modified Citrus Pectin (MCP) is, how it interacts with galectin‑3 and cancer, what the research shows, and what patients should know about safety, interactions, and integrative oncology considerations.

What Is Modified Citrus Pectin?

Modified citrus pectin (MCP) is a form of pectin derived from the peel and pulp of citrus fruits. Unlike regular pectin—which is too large to be absorbed—MCP is processed into smaller, low‑molecular‑weight fragments that the body can absorb more easily.

MCP is rich in galactoside residues, which give it a unique ability to bind to certain proteins involved in cancer biology, especially galectin‑3.

How MCP May Influence Cancer Biology

Much of MCP’s anticancer interest comes from its ability to bind and block galectin‑3, a protein involved in:

• Tumor growth[i]
• cell adhesion
• metastasis[ii]
• angiogenesis
• immune evasion
• apoptosis resistance

Galectin‑3 is overexpressed in many cancers and is associated with more aggressive disease and treatment resistance.[iii]

By binding to galectin‑3, MCP may interfere with several cancer-promoting pathways.[iv] [v]

We have a FREE online cancer workshop that lasts about 25 minutes.

Galectin‑3: The Protein at the Center of MCP Research

Galectin‑3 is a carbohydrate-binding lectin involved in:

• tumor cell adhesion
• tumor–endothelial interactions
• metastasis
• immune suppression
• treatment resistance

Research shows that galectin‑3 contributes to tumor immune escape and may reduce the effectiveness of immunotherapy. It also plays a role in cancer-associated inflammation and thrombosis (blood clots), further promoting tumor progression.[vi]

This makes galectin‑3 a compelling therapeutic target.

What the MCP Cancer Research Shows

MCP Physically Combined with Chemotherapy Drugs

Researchers are physically adding other cancer drugs to MCP to enhance their absorption, attachment to cancer cells, and treatment effectiveness.[vii] [viii] [ix]

Prostate Cancer and Modified Citrus Pectin

A long-term phase II clinical trial found that MCP improved PSA doubling time in 75–90% of men with non-metastatic biochemically relapsed prostate cancer.[x]

Another clinical report showed that MCP stabilized PSA and slowed progression in a majority of participants.

Breast Cancer and Modified Citrus Pectin

Modified citrus pectin inhibited breast cancer development in mice by targeting immune cells in the low-oxygen environment around and in tumors.[xi]

MCP enhanced cancer drug therapy in triple-negative breast cancer laboratory studies. [xii]

Colon Cancer and Modified Citrus Pectin

A review of pectin and MCP found evidence of:

• antiproliferative
• anti-inflammatory
• anti-metastatic
• pro-apoptotic (encourages cancer cell death)

effects in colorectal cancer models.[xiii] [xiv]

Melanoma and Modified Citrus Pectin

In a well-established melanoma model, MCP reduced lung metastasis by more than 90% in B16‑F1 mice.

Leukemia and Modified Citrus Pectin

MCP protected against carcinogenic signaling in C. elegans and has been shown to influence cancer-related pathways and immune activity in leukemia models.

Laboratory Cell and Animal Studies - Modified Citrus Pectin Shows Impact Against:

• Bladder Cancer[xv]
• Colorectal Cancer
• Gastric Cancer[xvi] [xvii]
• Liver Cancer[xviii]
• Lung Cancer[xix]
• Ovarian Cancer[xx]
• Pancreatic Cancer[xxi]
• Thyroid Cancer[xxii] [xxiii]

General Metastasis Research and Modified Citrus Pectin

Multiple studies show MCP interferes with:[xxiv]

• cancer cell aggregation
• adhesion
• endothelial attachment

These are key steps in metastasis.

Metastasis is one of the most dangerous aspects of cancer. MCP appears to reduce metastatic potential by:

• blocking galectin‑3
• preventing tumor cell clumping
• reducing adhesion to blood vessel walls
• interfering with tumor cell migration

Animal models show reduced metastasis in prostate, colon, breast, pancreatic and melanoma cancers.[xxv] [xxvi]

MCP and Chemotherapy, Radiation & Immunotherapy

Chemotherapy and Modified Citrus Pectin

Some research suggests MCP may enhance the anticancer effects of chemotherapy in preclinical models.[xxvii] [xxviii] [xxix] [xxx] MCP may also protect the kidneys from damage caused by chemotherapy.[xxxi]

Radiation Therapy and Modified Citrus Pectin

MCP has been reported to support the effectiveness of radiotherapy in animal studies, though human data are limited.[xxxii]

Immunotherapy and Modified Citrus Pectin

Galectin‑3 contributes to immune evasion and resistance to checkpoint inhibitors. Blocking galectin‑3 is being explored as a strategy to improve immunotherapy response.

MCP, as a galectin‑3 binder, is of interest in this area, though clinical trials are still needed.

How MCP Is Taken

General information from research and supplement manufacturers indicates MCP is typically available as:

• powder
• capsules

Researchers have used 5 grams three times daily in human studies.[xxxiii]

It is often taken on an empty stomach, but patients should always consult their integrative healthcare team before using any supplement.

Pectasol – Modified Citrus Pectin is available through Fullscripts with a 10% discount.

Potential Side Effects of Modified Citrus Pectin

According to Cancer Research UK, MCP may cause:

• diarrhea
• stomach discomfort
• gas

These effects are generally mild and self-limited.

Potential Interactions of Modified Citrus Pectin With Medications & Supplements

Because MCP is a soluble fiber and may influence absorption, it could theoretically affect:

• oral medications
• mineral absorption
• other supplements

Manufacturers state that it is so well absorbed that it has minimal impact on nutrient absorption. Patients should discuss MCP with their integrative healthcare team to avoid unintended interactions.

Modified Citrus Pectin Potential Interactions With Chemotherapy, Radiation & Immunotherapy

General considerations:

• MCP may influence immune pathways (galectin‑3) that overlap with immunotherapy mechanisms.
• MCP may affect the absorption of oral chemotherapy if taken at the same time.
• MCP’s fiber-like properties may influence the timing of other supplements.

Patients should always coordinate the use of supplements with their integrative oncology team.

Summary of Modified Citrus Pectin and Cancer

Modified citrus pectin is a unique, absorbable form of pectin that binds to galectin‑3, a protein deeply involved in cancer progression, metastasis, immune evasion, and treatment resistance.

Research—including animal studies, cell studies, and human clinical trials—suggests MCP may:

• slow cancer progression
• reduce metastasis
• improve PSA doubling time in prostate cancer
• influence cancer-related pathways
• support integrative oncology strategies

More large-scale human trials are needed, but MCP remains one of the most researched natural galectin‑3 inhibitors.

Check out our Cancer Coaching Program

Educational & FDA Supplement Disclaimer

This content is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Dietary supplements are not reviewed or approved by the FDA for cancer treatment. Always consult your healthcare provider before making changes to your medical, nutritional, or supplement plan.

[i] Wang, L., Li, Y., Yu, L., Zhang, X., Zhao, L., Gong, F., Yang, X., & Guo, X. (2020). Galectin-3 expression and secretion by tumor-associated macrophages in hypoxia promotes breast cancer progression. Biochemical Pharmacology, 178, 114113. https://doi.org/10.1016/j.bcp.2020.114113

[ii] Emran, T. B., Islam, F., Mitra, S., Paul, S., Nath, N., Khan, Z., Das, R., Chandran, D., Sharma, R., Gonçalves Lima, C. M., Al Awadh, A. A., Almazni, I. A., Alhasaniah, A. H., & F Guiné, R. P. (2022). Pectin: A Bioactive Food Polysaccharide with Cancer Preventive Potential. Molecules, 27(21), 7405. https://doi.org/10.3390/molecules27217405

[iii] Wu, Y., An, G., Tong, J., Zhang, W., Tian, Z., Dong, B., Liu, X., Zhao, L., Ye, C., Liu, J., Zhao, W., & Ma, H. (2025). Galectin-3 in tumor-stromal cells enhances gemcitabine resistance in pancreatic adenocarcinoma by suppressing oxidative phosphorylation. Genes & Diseases, 12(5), 101702. https://doi.org/10.1016/j.gendis.2025.101702

[iv] Kassab, A. E. (2025). The Most recent updates on pectin in Cancer therapy: A review. International Journal of Biological Macromolecules, 326, 147331. https://doi.org/10.1016/j.ijbiomac.2025.147331

[v] Salehi, F., Behboudi, H., Kavoosi, G., & Ardestani, S. K. (2018). Oxidative DNA damage induced by ROS-modulating agents with the ability to target DNA: A comparison of the biological characteristics of citrus pectin and apple pectin. Scientific Reports, 8(1), 13902. https://doi.org/10.1038/s41598-018-32308-2

[vi] Wdowiak, K., Francuz, T., Kubeczko, M., Grochoła, I., & Wojnar, J. (2018). Galectin Targeted Therapy in Oncology: Current Knowledge and Perspectives. International Journal of Molecular Sciences, 19(1), 210. https://doi.org/10.3390/ijms19010210

[vii] Bai, S., Sun, Y., Cheng, Y., Ye, W., Jiang, C., Liu, M., Ji, Q., Zhang, B., Mei, Q., Liu, D., & Zhou, S. (2021). MCP mediated active targeting calcium phosphate hybrid nanoparticles for the treatment of orthotopic drug-resistant colon cancer. Journal of Nanobiotechnology, 19, 367. https://doi.org/10.1186/s12951-021-01115-9

[viii] Sabra, R., Billa, N., & Roberts, C. J. (2019). Cetuximab-conjugated chitosan-pectinate (modified) composite nanoparticles for targeting colon cancer. International Journal of Pharmaceutics, 572, 118775. https://doi.org/10.1016/j.ijpharm.2019.118775

[ix] Subudhi, M. B., Jain, A., Jain, A., Hurkat, P., Shilpi, S., Gulbake, A., & Jain, S. K. (2015). Eudragit S100 Coated Citrus Pectin Nanoparticles for  Colon Targeting of 5-Fluorouracil. Materials, 8(3), 832-849. https://doi.org/10.3390/ma8030832

[x] Keizman, D., Frenkel, M., Peer, A., Rosenbaum, E., Sarid, D., Leibovitch, I., Mano, R., Yossepowitch, O., Wolf, I., Geva, R., Margel, D., Rouvinov, K., Stern, A., Dresler, H., Kushnir, I., & Eliaz, I. (2023). Modified Citrus Pectin Treatment in Non-Metastatic Biochemically Relapsed Prostate Cancer: Long-Term Results of a Prospective Phase II Study. Nutrients, 15(16), 3533. https://doi.org/10.3390/nu15163533

[xi] Wang, L., Zhao, L., Gong, F., Sun, C., Du, D., Yang, X., & Guo, X. (2022). Modified citrus pectin inhibits breast cancer development in mice by targeting tumor-associated macrophage survival and polarization in hypoxic microenvironment. Acta Pharmacologica Sinica, 43(6), 1556-1567. https://doi.org/10.1038/s41401-021-00748-8

[xii] Balakrishnan B, Subramanian S, Mallia MB, et al. Multifunctional Core–Shell Glyconanoparticles for Galectin-3-Targeted, Trigger-Responsive Combination Chemotherapy. Biomacromolecules. 2020;21(7):2645-2660. doi: https://doi.org/10.1021/acs.biomac.0c00358  

[xiii] Fan, J., Zhu, J., Zhu, H., Zhang, Y., & Xu, H. (2024). Potential therapeutic target for polysaccharide inhibition of colon cancer progression. Frontiers in Medicine, 10, 1325491. https://doi.org/10.3389/fmed.2023.1325491n

[xiv] Chen, L., Hao, M., Yan, J., Sun, L., Tai, G., Cheng, H., & Zhou, Y. (2021). Citrus-derived DHCP inhibits mitochondrial complex II to enhance TRAIL sensitivity via ROS-induced DR5 upregulation. The Journal of Biological Chemistry, 296, 100515. https://doi.org/10.1016/j.jbc.2021.100515

[xv] Fang, T., Liu, D., Ning, H., Liu, D., Sun, J., Huang, X., Dong, Y., Geng, M., Yun, S., Yan, J., & Huang, R. (2018). Modified citrus pectin inhibited bladder tumor growth through downregulation of galectin-3. Acta Pharmacologica Sinica, 39(12), 1885-1893. https://doi.org/10.1038/s41401-018-0004-z

[xvi] Sun, C., Ma, Q., Feng, L., Ji, J., Du, D., Shang, P., & Guo, X. (2025). MCP-enhanced SOD3 activity inhibits gastric cancer and potentiate chemotherapy via modulating EGFR signaling. Life Sciences, 362, 123358. https://doi.org/10.1016/j.lfs.2024.123358

[xvii] Wang S, Li P, Lu SM, Ling ZQ. Chemoprevention of Low-Molecular-Weight Citrus Pectin (LCP) in Gastrointestinal Cancer Cells. International Journal of Biological Sciences. 2016;12(6):746-756. doi: https://doi.org/10.7150/ijbs.13988

[xviii] Wu XQ, Fu JY, Mei RY, et al. Inhibition of Liver Cancer HepG2 Cell Proliferation by Enzymatically Prepared Low-molecular Citrus Pectin. Curr Pharm Biotechnol. 2022;23(6):861-872. doi:10.2174/1389201022666210729122631 https://pubmed.ncbi.nlm.nih.gov/34376132/

[xix] Sabra, R., Billa, N., & Roberts, C. J. (2019). Cetuximab-conjugated chitosan-pectinate (modified) composite nanoparticles for targeting colon cancer. International Journal of Pharmaceutics, 572, 118775. https://doi.org/10.1016/j.ijpharm.2019.118775

[xx] Hossein, G., Halvaei, S., Heidarian, Y., Dehghani-Ghobadi, Z., Hassani, M., Hosseini, H., Naderi, N., & Hassani, S. S. (2019). Pectasol-C Modified Citrus Pectin targets Galectin-3-induced STAT3 activation and synergize paclitaxel cytotoxic effect on ovarian cancer spheroids. Cancer Medicine, 8(9), 4315-4329. https://doi.org/10.1002/cam4.2334

[xxi] Schöll-Naderer, M., Helm, O., Spencker, J., Pfeifer, L., Rätsch, T., Sebens, S., & Classen, B. (2020). Plant-derived saccharides and their inhibitory potential on metastasis associated cellular processes of pancreatic ductal adenocarcinoma cells. Carbohydrate Research, 490, 107903. https://doi.org/10.1016/j.carres.2019.107903

[xxii] Zheng J., Lu W., Wang C., Xing Y., Chen X., Ai Z. Galectin-3 induced by hypoxia promotes cell migration in thyroid cancer cells. Oncotarget. 2017; 8: 101475-101488. Retrieved from https://www.oncotarget.com/article/21135/text/

[xxiii] Menachem, A., Bodner, O., Pastor, J., Raz, A., & Kloog, Y. (2015). Inhibition of malignant thyroid carcinoma cell proliferation by Ras and galectin-3 inhibitors. Cell Death Discovery, 1(1), 15047. https://doi.org/10.1038/cddiscovery.2015.47

[xxiv] Eliaz, I., & Raz, A. (2019). Pleiotropic Effects of Modified Citrus Pectin. Nutrients, 11(11), 2619. https://doi.org/10.3390/nu11112619

[xxv] Schöll-Naderer, M., Helm, O., Spencker, J., Pfeifer, L., Rätsch, T., Sebens, S., & Classen, B. (2020). Plant-derived saccharides and their inhibitory potential on metastasis associated cellular processes of pancreatic ductal adenocarcinoma cells. Carbohydrate Research, 490, 107903. https://doi.org/10.1016/j.carres.2019.107903

[xxvi] Do Prado, S. B. R., Shiga, T. M., Harazono, Y., Hogan, V. A., Raz, A., Carpita, N. C., & Fabi, J. P. (2019). Migration and proliferation of cancer cells in culture are differentially affected by molecular size of modified citrus pectin. Carbohydrate Polymers, 211, 141-151. https://doi.org/10.1016/j.carbpol.2019.02.010

[xxvii] Sun, C., Ma, Q., Feng, L., Ji, J., Du, D., Shang, P., & Guo, X. (2025). MCP-enhanced SOD3 activity inhibits gastric cancer and potentiate chemotherapy via modulating EGFR signaling. Life Sciences, 362, 123358. https://doi.org/10.1016/j.lfs.2024.123358

[xxviii] Wang, L., Li, Y., Yu, L., Zhang, X., Zhao, L., Gong, F., Yang, X., & Guo, X. (2020). Galectin-3 expression and secretion by tumor-associated macrophages in hypoxia promotes breast cancer progression. Biochemical Pharmacology, 178, 114113. https://doi.org/10.1016/j.bcp.2020.114113

[xxix] Balakrishnan B, Subramanian S, Mallia MB, et al. Multifunctional Core–Shell Glyconanoparticles for Galectin-3-Targeted, Trigger-Responsive Combination Chemotherapy. Biomacromolecules. 2020;21(7):2645-2660. doi: https://doi.org/10.1021/acs.biomac.0c00358

[xxx] Hossein, G., Halvaei, S., Heidarian, Y., Dehghani-Ghobadi, Z., Hassani, M., Hosseini, H., Naderi, N., & Hassani, S. S. (2019). Pectasol-C Modified Citrus Pectin targets Galectin-3-induced STAT3 activation and synergize paclitaxel cytotoxic effect on ovarian cancer spheroids. Cancer Medicine, 8(9), 4315-4329. https://doi.org/10.1002/cam4.2334

[xxxi] Li H, Yang S, Li J, Feng J. Galectin 3 inhibition attenuates renal injury progression in cisplatin-induced nephrotoxicity. Bioscience Reports. 2018;38(6). Doi :https://doi.org/10.1042/bsr20181803

[xxxii] Conti, S., Vexler, A., Hagoel, L., Kalich-Philosoph, L., Corn, B. W., Honig, N., Shtraus, N., Meir, Y., Ron, I., Eliaz, I., & Lev-Ari, S. (2018). Modified Citrus Pectin as a Potential Sensitizer for Radiotherapy in Prostate Cancer. Integrative Cancer Therapies. https://doi.org/10.1177/1534735418790382

[xxxiii] Keizman, D., Frenkel, M., Peer, A., Rosenbaum, E., Sarid, D., Leibovitch, I., Mano, R., Yossepowitch, O., Wolf, I., Geva, R., Margel, D., Rouvinov, K., Stern, A., Dresler, H., Kushnir, I., & Eliaz, I. (2023). Modified Citrus Pectin Treatment in Non-Metastatic Biochemically Relapsed Prostate Cancer: Long-Term Results of a Prospective Phase II Study. Nutrients, 15(16), 3533. https://doi.org/10.3390/nu15163533