Ulcerative Colitis — NZ Condition Guide | KiwiMeds

What is Ulcerative Colitis?

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) that causes chronic inflammation and ulcers in the colon (large intestine) and rectum. Unlike Crohn’s disease, UC only affects the colon and the inflammation is continuous from the rectum upwards.

Overview

UC symptoms include bloody diarrhoea (a hallmark symptom), rectal bleeding and mucus, abdominal cramping and pain, urgent need to defecate, fatigue, weight loss, and fever during flares. UC has periods of active disease (flares) and remission. Severity ranges from mild to severe. Fulminant colitis — a rare severe complication — is a medical emergency. Long-standing extensive UC increases colorectal cancer risk, requiring regular surveillance colonoscopy.

Treatment in New Zealand

UC treatment depends on disease extent and severity. Aminosalicylates (mesalazine, sulfasalazine) are first-line for mild-moderate UC — both funded by Pharmac. Corticosteroids (prednisone, budesonide) are used for flares. Immunosuppressants (azathioprine, 6-mercaptopurine) maintain remission. Biologics (infliximab, adalimumab, vedolizumab) are funded by Pharmac for moderate-severe UC not responding to conventional therapy. Surgery (colectomy) is curative for UC, unlike Crohn’s disease.

NZ-Specific Information

Crohn’s and Colitis NZ (ccnz.org.nz) provides support. Pharmac funds multiple treatments for UC. Specialist gastroenterology care is important for moderate-severe UC.

Frequently Asked Questions

Is UC related to bowel cancer? Long-standing UC increases colorectal cancer risk — regular surveillance colonoscopy (every 1–3 years) is recommended after 8–10 years of extensive disease. Does diet cause UC? Diet does not cause UC but certain foods may trigger symptoms during flares. A dietitian can help identify individual triggers.

Supplements That May Support Management

⚠️ Important: The supplements listed below have varying levels of clinical evidence. They are not a substitute for prescribed medications and should only be considered as adjunctive support under the guidance of a qualified healthcare professional. Always inform your GP or pharmacist before commencing any supplement, as interactions with prescribed medicines are possible.

• Vitamin D — Vitamin D deficiency is prevalent in ulcerative colitis and is associated with increased disease activity, flare frequency, and colectomy risk. Supplementation guided by serum levels is a standard component of UC nutritional management.
• Iron — Chronic blood loss from colonic inflammation causes iron deficiency anaemia in the majority of people with active UC. Iron replacement (oral or IV as tolerated and directed by your gastroenterologist) is essential for quality of life and haematological recovery.
• Omega-3 Fatty Acids — Omega-3 supplementation has demonstrated modest reductions in relapse rates in UC maintenance through reduction of mucosal prostaglandin E2 and leukotriene B4. While evidence is less robust than in Crohn’s, it may provide adjunctive benefit.
• Probiotics (VSL#3, Bifidobacterium) — Probiotic supplementation has the strongest evidence in UC compared to Crohn’s. VSL#3 (a high-dose multi-strain probiotic) has demonstrated induction and maintenance of remission in mild-to-moderate UC in randomised trials, serving as a complementary approach.
• Calcium and Vitamin D — Long-term corticosteroid use in UC significantly increases bone density loss. Calcium and vitamin D supplementation is standard alongside steroid therapy.

Relevant Vaccinations

Individuals living with ulcerative colitis may benefit from the following vaccinations. Please discuss your vaccination status with your GP or practice nurse, as eligibility and funding through the New Zealand National Immunisation Schedule may apply.

• Influenza (annual) — Influenza can trigger UC flares. People on immunosuppressive therapy for UC are at increased infection risk. Annual vaccination is strongly recommended.
• Pneumococcal — Immunosuppression from UC medications (azathioprine, biologics, tofacitinib) increases pneumococcal risk. Vaccination before immunosuppressive therapy is preferred.
• Hepatitis B — Required before commencing biologic therapy. Latent hepatitis B can reactivate with biologic immunosuppression.
• CAUTION: Live vaccines contraindicated on immunosuppression — Live vaccines must not be administered to people on significant immunosuppressive therapy. Discuss all vaccinations with your gastroenterologist.
• COVID-19 — Maintaining COVID-19 vaccination is strongly recommended for people with UC on immunosuppressive therapy.

Dietary Guidance

Evidence-based dietary modifications play a meaningful role in the management of ulcerative colitis. The following foods are generally recommended as part of a balanced, condition-appropriate diet. A referral to a registered dietitian may be beneficial for personalised nutritional planning.

• Low-residue diet during active flares — Reduced dietary fibre during active UC reduces intestinal transit, bowel frequency, and mechanical mucosal irritation. Introduction of fibre is recommended during remission.
• Soluble fibre in remission (oats, psyllium, cooked carrots) — Soluble fibre fermentation produces short-chain fatty acids (particularly butyrate) that are the primary fuel for colonocytes and support mucosal healing in UC remission.
• Omega-3 rich foods (oily fish) — Regular dietary omega-3 reduces mucosal inflammation. Aim for 2–3 servings of oily fish per week.
• Probiotic-rich fermented foods (yoghurt, kefir) — Support colonic microbiome diversity relevant to UC mucosal immunity.
• Identify and limit personal trigger foods — Common UC triggers include raw vegetables, high-fibre foods, spicy food, caffeine, alcohol, and dairy (in those with secondary lactose intolerance). An IBD-specialised dietitian can help optimise the diet.

Related Conditions & Medications

Related conditions: Crohn’s Disease, IBS.