Surgical Support for Colorectal Cancer

Whole-person approaches to preparing for and recovering from colorectal cancer surgery

In partnership with KNOW Oncology—a searchable website that summarizes human studies on natural health products and nutrition in cancer care. Your clinicians can use it to look up the latest evidence by cancer type, supporting shared decisions that fit your goals and values. Alongside the KNOW team, comprised of Naturopathic Doctors, we’ve written a short guide on evidence-based approaches to support surgery preparation and recovery for people with colorectal cancer.

Supplements to prepare for surgery 

Probiotics 

There are many strains of probiotics available, selecting the right one with guidance from your care team can help ensure you are taking the best strain for you.

• Probiotics have been shown to reduce rates of infection, pneumonia, and diarrhea after surgery for colorectal cancer.¹Gao S, Liao X et al. Probiotics/synbiotics supplementation reduce the infection incidence in patients undergoing resection for colorectal cancer: an umbrella review. Frontiers in Microbiology. 2025 Sep 11;16:1635409.
• Probiotics may even help shorten your hospital stay by a day or more.²Zhang Y, Hu J et al. Exploring the clinical value of probiotics in the perioperative management of colorectal cancer: Meta-analysis with trial sequential analysis. Oncology Letters. 2025 Sep 9;30(5):515.
• Lactobacillus, Bifidobacterium, and multi-strain combinations appear to be most effective for reducing postoperative infections.³Zhang Y, Hu J et al. Exploring the clinical value of probiotics in the perioperative management of colorectal cancer: Meta-analysis with trial sequential analysis. Oncology Letters. 2025 Sep 9;30(5):515.
• Starting probiotics within 5 days of surgery and continuing for at least 10 days after surgery may be most effective for reducing severity and incidence of infections.⁴Araújo MM, Montalvão-Sousa TM et al. The effect of probiotics on postsurgical complications in patients with colorectal cancer: a systematic review and meta-analysis. Nutrition Reviews. 2023 Apr 11;81(5):493-510.

Whey protein 

• Supplementing with whey protein before and after surgery, in addition to exercise and psychological support, may lead to fewer complications and aid recovery after colorectal surgery.⁵Srinivasaraghavan N, Das N et al. Effect of Whey Protein Supplementation on Perioperative Outcomes in Patients with Cancer—A Systematic Review and Meta-Analysis (PROSPERO 2020: CRD42020188666). Nutrition and Cancer. 2022;74(7):2351-2364.
• Talk with your doctor about appropriate dosage and concerns to watch out for.

Iron supplementation 

• Iron therapy before surgery can improve hemoglobin and may substantially reduce the need for blood transfusions during surgery.⁶Tang G, Zhang L et al. Iron Supplementation Effectively Ameliorates Anemia and Reduces the Need for Blood Transfusion in Patients Undergoing Colorectal Cancer Surgery: A Meta-Analysis. Nutrition and Cancer. 2022;74(7):2303-2312.
• Talk with your doctor about appropriate dosing for your needs.

Omega-3 fatty acids 

• Omega-3 supplementation may reduce infections and inflammation after surgery for colorectal cancer.⁷Orellana-Jaen A, Corres P et al. Effects of Preoperative Immunonutrition on Postoperative Complications in Patients Undergoing Colorectal Cancer Resection: A Systematic Review and Meta-analysis. Nutrition Reviews. Advance online publication. 2025 Dec 12:nuaf276.
• Omega-3 supplementation has also been shown to reduce post-surgery hospital stay by 2 days on average.⁸Xie H, Chang YN. Omega-3 polyunsaturated fatty acids in the prevention of postoperative complications in colorectal cancer: a meta-analysis. OncoTargets and Therapy. 2016 Dec 9;9:7435–7443.
• While there has historically been concern about bleeding risk with omega-3 supplements, several high-quality studies have shown no difference in bleeding events among surgery patients using omega-3 supplements.⁹Javaid M, Kadhim K et al. Bleeding Risk in Patients Receiving Omega-3 Polyunsaturated Fatty Acids: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Journal of the American Heart Association. 2024 May 14;13(10):e032390; Akintoye E, Sethi P et al. Fish Oil and Perioperative Bleeding. Circulation. Cardiovascular Quality and Outcomes. 2018 Nov;11(11):e004584.
• Talk with your doctor about an appropriate supplement regimen for you.

Melatonin

• Five mg of melatonin administered at 12 and 2 hours before surgery has been shown to reduce delirium symptoms after surgery for elderly patients.¹⁰Elbakry AA, El-Desoky IM et al. The impact of melatonin on postoperative delirium in geriatric patients after colorectal surgery: a randomized placebo-controlled trial. Minerva Anestesiologica. 2024 Jun;90(6):509-519.

Post-surgery support

Prunes

• Eating dried prunes daily for at least 2 weeks after surgery may significantly reduce complications after surgery caused by Low Anterior Resection Syndrome (LARS) such as diarrhea, constipation, appetite loss, and sleep disturbance.¹¹Pyo DH, Shin JK et al. Effects of prune consumption on the incidence of low anterior resection syndrome: a randomized controlled trial. Annals of Coloproctology. 2025 Dec 12;41(6):510–518.

Gum chewing

• Chewing gum for more than 10 minutes, 3-4 times a day has been shown to substantially reduce the occurrence of intestine blockages after surgery and improve recovery rates.¹²Irani JL, Hedrick TL et al. Clinical practice guidelines for enhanced recovery after colon and rectal surgery from the American Society of Colon and Rectal Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons. Surgical Endoscopy. 2022 Dec 14;37(1):5–30; Sinz S, Warschkow R et al. Gum Chewing and Coffee Consumption but not Caffeine Intake Improve Bowel Function after Gastrointestinal Surgery: a Systematic Review and Network Meta-analysis. Journal of Gastrointestinal Surgery : Official Journal of the Society for Surgery of the Alimentary Tract. 2023 Jun 5;27(8):1730–1745.

Coffee consumption 

• Drinking coffee after surgery may reduce time to first bowel movement and shorten your hospital stay.¹³Irani JL, Hedrick TL et al. Clinical practice guidelines for enhanced recovery after colon and rectal surgery from the American Society of Colon and Rectal Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons. Surgical Endoscopy. 2022 Dec 14;37(1):5–30; Sinz S, Warschkow R et al. Gum Chewing and Coffee Consumption but not Caffeine Intake Improve Bowel Function after Gastrointestinal Surgery: a Systematic Review and Network Meta-analysis. Journal of Gastrointestinal Surgery : Official Journal of the Society for Surgery of the Alimentary Tract. 2023 Jun 5;27(8):1730–1745.

This article was produced through a collaboration of KNOWintegrativeoncology.org and CancerChoices.