The importance of nutrition
Adequate nutrition is essential throughout rectal cancer treatment. Proper nutrition helps to:
- Maintain weight and muscle mass
- Support the immune system
- Tolerate treatment (chemotherapy, radiotherapy)
- Faster postoperative recovery
- Heal wounds and the anastomosis
During chemoradiotherapy
Common problems
- Diarrhea — a frequent effect of pelvic radiotherapy
- Nausea — associated with chemotherapy
- Loss of appetite
- Fatigue
- Rectal mucosa irritation (radiation proctitis)
Recommendations
- Small, frequent meals — 5-6 meals a day instead of 3 large ones
- Avoid irritating foods — spicy, fatty, very high-fiber
- Reduce dairy — if lactose intolerance develops (common during radiotherapy)
- Plenty of fluids — minimum 1.5-2 liters per day
- Well-tolerated foods — rice, pasta, white bread, bananas, boiled potatoes, boiled chicken
- Protein supplements — if dietary intake is insufficient
After surgery
First weeks
- Liquid diet followed by semi-solid diet, then solid
- Small portions — the stomach and intestine readjust gradually
- Avoid gas-producing foods — beans, cabbage, broccoli, beer
- Adequate protein — essential for surgical healing
Reintroducing foods
- Introduce one new food every 2-3 days
- Note what you tolerate well and what causes problems
- Chew each bite well
- Do not drink fluids in excess during the meal
Eating with LARS
If you have low anterior resection syndrome, certain dietary adjustments may improve symptoms:
- Soluble fiber (oats, psyllium) — can thicken stool
- Avoid foods that thin stool — plums, alcohol, excess coffee
- Meal timing — eating at regular times helps with predictable transit
- Food diary — recording foods and their effects helps identify triggers
Eating with a stoma
Ileostomy
- Risk of dehydration — fluid losses are greater
- Electrolytes — monitoring sodium and potassium
- Avoiding blockages — chew well, avoid large pieces of fibrous food
- Increased hydration — oral rehydration solutions if stool is very liquid
Colostomy
- Diet is less restrictive than with an ileostomy
- Notice which foods change stool consistency or produce odor
- Eating at regular times helps with predictable transit
Long-term recommendations
- Mediterranean diet — rich in fruits, vegetables, fish, whole grains, olive oil
- Reduce processed meat — sausages, ham, bacon
- Limit red meat — maximum 500g (about 1 lb) per week
- Reduce sugar and ultra-processed foods
- Maintain a normal weight — BMI 18.5-25
- Regular physical activity — minimum 150 minutes/week of moderate exercise
Consult a dietitian specialized in oncology for a personalized plan adapted to your situation.