Cancer: risk factors and modification of diet
Many cancers are linked to tobacco, alcohol, obesity and certain foods. Patients need 25-30 kcal/kg and 1-1.5 g protein/kg in small, frequent, energy-dense meals.
Diet and lifestyle risk factors
| Risk factor | Cancer linked | Prevention |
|---|---|---|
| Tobacco (smoking, gutka, khaini) and betel quid with areca nut | Mouth, throat, lung, oesophagus, bladder | No tobacco in any form |
| Alcohol | Mouth, oesophagus, liver, breast, colon | Avoid alcohol |
| Obesity and inactivity | Breast (after menopause), colon, uterus, kidney, oesophagus | Healthy weight; daily activity |
| Processed meat (IARC Group 1) and red meat (Group 2A) | Colorectal | Limit red meat; avoid processed meats |
| Aflatoxin from mouldy groundnuts and grains | Liver | Dry storage; discard mouldy or shrivelled nuts and grains |
| Salted, smoked and pickled foods | Stomach | Fresh foods, refrigeration, less salt |
| Very hot drinks above 65 °C (IARC Group 2A) | Oesophagus | Let tea and coffee cool a little |
| Low fruit, vegetable and fibre intake | Colorectal, others | Five servings of fruit and vegetables; whole grains and pulses |
| Infections: HPV, hepatitis B and C, H. pylori | Cervix, liver, stomach | HPV and hepatitis B vaccines; safe food and water |
Why cancer patients lose weight (cachexia)
Cancer cachexia is a wasting syndrome with loss of muscle, with or without fat loss, that ordinary feeding cannot fully reverse. The tumour and the body's response release cytokines (TNF-α, IL-1, IL-6) that cause loss of appetite (anorexia), raise energy use, speed up protein breakdown, fat breakdown and glucose production from protein. Treatment adds nausea, mouth sores and taste changes. Weight loss lowers tolerance to treatment and survival, so every cancer patient should be screened for malnutrition at diagnosis and regularly after.
Dietary principles
| Nutrient | Recommendation | Why |
|---|---|---|
| Energy | About 25-30 kcal/kg; energy-dense foods (add ghee, nut powders, milk powder to dishes) | Prevents weight loss when the patient can eat only small amounts |
| Protein | Above 1 g/kg, up to 1.5 g/kg: milk, curd, paneer, egg, fish, chicken, dal, soya | Limits muscle wasting and helps repair after treatment |
| Fat | Can be a larger share of energy if tolerated; omega-3 (fish) may help appetite and weight in advanced cancer | Fat gives the most energy in the least volume |
| Vitamins and minerals | About the RDA from food; avoid high-dose supplements unless a deficiency is proven | High-dose antioxidants may interfere with treatment |
| Fluid | 2-3 litres a day; more with vomiting or diarrhoea | Prevents dehydration and helps clear drugs |
| Meal pattern | 6-8 small meals; eat when appetite is best (often morning) | Large meals cause early fullness |
| Support | Oral supplements first; tube feeding if intake stays below about 60% of needs for 1-2 weeks despite supplements (ESPEN); parenteral only if the gut fails | Step up support before the patient becomes severely malnourished |
Worked example: energy and protein for a cancer patient
Mrs. Rani, 50 kg, is having chemotherapy for breast cancer and has lost weight. Work out her energy and protein needs using ESPEN ranges.
- Energy (25-30 kcal/kg): 25 × 50 = 1,250 kcal; 30 × 50 = 1,500 kcal. Because she is losing weight, aim for the top: about 1,500 kcal.
- Protein (1.0-1.5 g/kg): 1.0 × 50 = 50 g; 1.5 × 50 = 75 g. Aim for about 60-75 g.
- Spread over 6 meals: 1,500 ÷ 6 = about 250 kcal and 75 ÷ 6 = about 12-13 g protein per meal at the top of the range.
About 1,500 kcal and 60-75 g protein a day, in 6 small meals of about 250 kcal each.
Foods and a sample one-day menu (high-energy, high-protein)
| Item | Details |
|---|---|
| Include | Milk and milkshakes, curd, paneer, eggs, fish, chicken, soft dal, soya, nut and seed powders, ragi malt, fruits, cooked vegetables, oral nutrition supplements |
| Avoid or limit | Alcohol, tobacco, processed and charred meats, unwashed raw foods during low blood counts, high-dose supplements, unproven 'cancer-cure' diets |
| Early morning | Milk with ragi malt and 1 tsp of nut powder |
| Breakfast | Vegetable upma with peanuts; boiled egg |
| Mid-morning | Banana milkshake with milk powder |
| Lunch | Rice with ghee, dal, fish or paneer curry, cooked vegetables, curd |
| Evening | Paneer or egg sandwich; tender coconut water |
| Dinner | Soft chapati with ghee, chicken or soya curry, vegetable kootu |
| Bedtime | Custard or an oral nutrition supplement |
In the oncology ward, the dietitian screens weight every visit, enriches hospital food with milk powder, ghee and nut powders, and starts supplements early. Families often try 'starve the cancer' diets; explain that starving weakens the patient, not the tumour.
2 marks: “What is cancer cachexia?” A wasting syndrome of ongoing muscle loss, with or without fat loss, that ordinary feeding cannot fully reverse; caused by tumour factors and cytokines.
5 marks: “Explain the dietary risk factors for cancer.” Tobacco and areca nut, alcohol, obesity, processed and red meat, aflatoxin, salted and smoked foods, very hot drinks, low fruit, vegetable and fibre intake, with the cancer linked to each.
10 marks: “Discuss the risk factors of cancer and the modification of diet for a cancer patient.” Risk factor table, cachexia, energy 25-30 kcal/kg and protein 1-1.5 g/kg with a calculation, fat, vitamins, fluid, meal pattern, nutrition support steps, menu.
Cancer plate: 'Little, often, rich': small frequent meals, rich in energy and protein. Prevention: no tobacco, no alcohol, keep slim, eat plants.