Cancer is increasingly developing in Vietnam as well as around the world due to many causes. In which, nutritional causes play an important role. Some carcinogenic factors have been identified in food: alphatoxin, heterocyclic amines, nitrosamines, fatty components that decompose at high temperatures, polycyclic aromatic hydrocarbons.... Therefore, it is necessary to have a reasonable diet to prevent and treat cancer.

Cancer patients need to undergo many very severe treatments (surgery, chemotherapy, radiotherapy), so they are often very tired, have poor appetite or cannot eat, vomit, feel nauseous, and have digestive disorders.

1. Nutritional needs

• Diet rich in starch, fiber, vitamins, minerals.
• Energy: Energy consumption in cancer patients is very high, averaging about 30 - 35 Kcal/kg/day. Some special cases may require up to 40 - 50 Kcal/kg/day.
• Protein: 12 - 20% of total energy. Animal protein accounts for 30% - 50% of total protein.
• Lipid: 18 - 25% of total energy, including: 1/3 saturated fatty acids, 1/3 monounsaturated fatty acids, 1/3 polyunsaturated fatty acids. EPA: 2g/24h.
• Carbohydrates: 60 - 70% of total energy.
• Provides adequate vitamins, minerals and fiber according to the needs of normal healthy people.
• Water intake: 40ml/kg body weight/day.
• Salt intake: 6g/day, should not exceed 10g/day.
  
  

2. Food choices 

Carbohydrates and lipids are the major sources of energy for the body. Carbohydrates for cancer patients are provided from cereals (rice, noodles...), corn, potatoes, cassava... and products made from them.

The popular belief, and still popular in our country today, is that people with cancer should not eat nutritious food (limited use of animal-based proteins). This is a misconception, because protein is a basic element that helps the body heal wounds, fight infections during and after surgery, chemotherapy and radiotherapy, and is a material that replenishes the body's lean mass lost due to increased catabolism. It also helps increase appetite while cancer patients always have anorexia and poor appetite.

An effective treatment for cancer cachexia is the use of EPA (Eicosapentaenoic Acid), an Omega-3 unsaturated fatty acid. Animal experiments and clinical trials on cancer patients have shown that EPA supplementation inhibits inflammatory cytokines and reduces metabolic disturbances in cachexia syndrome. Adequate energy and protein-rich nutrition, supplemented with 2 g EPA/day helps cancer patients improve their appetite, prevent cachexia, improve physical activity, and improve quality of life because malnutrition and weight loss are common in cancer patients. Unintentional weight loss of 5% also leads to reduced survival rates. Weight loss affects the survival rate of patients.

a. Foods to eat

• Meat, fish, eggs, milk, shrimp, crab….
• Rice, vermicelli, rice noodles, pho noodles, tubers...
• Vegetable oil (soybean oil, peanut oil, sesame oil...)
• Eat lots of green vegetables, ripe fruits, herbs, and high-fiber vegetables. You should eat 400-500g of vegetables and 200-400g of ripe fruits every day.
• Increase intake of foods rich in omega-3: Salmon, olive oil...
• Use foods rich in vitamins E, C, A, and Selenium which have antioxidant properties such as carrots, green bean sprouts, tomatoes, Malabar spinach, water spinach, etc.
• Eat lots of vegetables and fruits: bean sprouts, carrots, pumpkin, gac fruit, ripe papaya, dark green vegetables, Malabar spinach, water spinach, cabbage, tomatoes, soybeans...
• Spices: Onion, garlic, lemon, herbs...
• Vegetable oil, fish oil.
• Whole grains.
• Animal meat: should eat white meat (fish, poultry, birds), limit red meat: 100g/day.
• Tea: drink during the day, not at night

b. Foods to limit or avoid                          

• Limit foods processed at high temperatures, do not eat burnt foods, processed foods: sausages, hot dogs...
• Do not use spoiled food especially moldy nuts.
• Limit alcohol, beer, cigarettes...
• Eat less salt.
• Foods high in fatty acids include: grilled meats, smoked meats, stir-fried, fried, roasted dishes, cakes such as spring rolls...
• Industrially processed, prepackaged foods such as: canned foods, cold cuts.
• Limit drinking tea at night (should drink tea during the day).
• Carcinogenic foods: Some carcinogens are present in foods, most notably aflatoxins and nitrosamines. Aflatoxins are toxins produced by the mold Aspergillus flavus, found in moldy peanuts and some other foods due to improper storage conditions after harvest. Aflatoxins are potent experimental liver carcinogens and consuming aflatoxin-contaminated foods is a risk factor for liver cancer in humans. Some nitrosamines are also experimental carcinogens. Nitrosamines are formed in the small intestine by the combination of nitrites and amino acids. Nitrates are usually present in small amounts in foods, and a small number of people also use nitrates and nitrites to preserve meat against clostridium contamination. Therefore, monitoring the allowable dosage of these additives is very necessary. Many food dyes and sweeteners such as cyclamate are also experimentally carcinogenic, so hygiene regulations on dyes and additives must be strictly followed.
• Frying oil over and over again.
• Moldy foods such as: moldy peanuts, moldy beans, moldy pumpkin seeds, moldy roasted melon seeds...
• Stimulants such as: alcohol, beer, cigarettes.