Cancer involves mutated cells abnormally dividing and reproducing which spread throughout the body. It is one of the largest contributors to death in the US, responsible for nearly one out of every four deaths (American Cancer Society).
Nutrition and lifestyle have a major impact on risk factors and prevention of cancer, including diet, activity level, tobacco use, alcohol use, body weight, and exposure to carcinogens.
Nutrition and Carcinogens
Nutrition plays an important role in the prevention and treatment of cancer.
Fruits and vegetables: Fruits and vegetables contain essential nutrients that can inhibit carcinogens, such as antioxidants (vitamins A, C, and E, carotenoids, selenium, and zinc) and phytochemicals. Below is a list of phytochemicals and the foods they are present in:
- * Lycopene (red in color) – Found in tomatoes, pink grapefruit, and watermelon
- * Anthocyanins and polyphenols (red and purple in color) – Found in berries, grapes, red wine, and plums
- * Alpha- and beta-carotene (orange in color) – Found in carrots, mangoes, and pumpkin
- * Beta-cryptoxanthin and flavonoids (orange and yellow in color) – Found in cantaloupe, peaches, oranges, papaya, and nectarines
- * Lutein and zeaxanthin (yellow and green in color) – Found in spinach, avocados, honeydew, collard and turnip greens
- * Sulforaphanes and indoles (green in color) – Found in cabbage, broccoli, Brussels sprouts, and cauliflower
- * Allyl sulphides (white and green in color) – Found in leeks, onions, garlic, and chives
Fat: Research has shown a link between certain types of cancer and the amount of fat in the diet. Diets high in fat often contain an increased consumption of meat, in which there is also a link to increased colorectal cancer risk.
Diets higher in fat also tend to be higher in calories, contributing to being overweight or obese.
However, eating more omega-3 fatty acids (from fatty fish, flaxseed oil, and walnuts) in relation to omega-6 fatty acids (found in corn oil, safflower oil, and sunflower oil) can have a potentially reducing risk of certain cancers, specifically of the colon and prostate.
Protein: Diets high in protein typically result in larger intakes of red meat and fat, and lower intakes of fiber. Recommendations for lowering cancer risk and improving overall health encourage the intake of plant foods and limiting foods from animal sources, specifically red meat and processed meats.
Alcohol: Alcohol consumption is associated with an increased risk of developing cancer of the mouth, larynx, pharynx, esophagus, lungs, colon, rectum, liver, and breast. When alcohol consumption is paired with tobacco use, the cancer risk increases as well.
Nutrition Management of Cancer
Energy: Determining the patient’s energy needs is important to maintaining their body weight and preventing further weight loss associated with cancer. Standardized energy requirement equations will be useful in calculating the patient’s needs, or to quickly estimate energy needs, the following guidelines may be used:
- * Weight gain: 30-40 cals/kg/d
- * Weight maintenance: 25-30 cals/kg/d
- * Patient with hypermetabolism or stressed: 35 cals/kg/d
- * Sepsis: 25-30 cals/kg/d
- * Obese: 21-25 cals/kg/d
Protein: Protein needs are increased during times of illness and stress. The additional protein is required to repair and rebuild tissue affected by cancer therapy and to maintain a healthy immune system. The first goal is to make sure the patient’s energy needs are being met, otherwise, the body will use the lean body mass stores as a source of energy. When determining protein needs, consider the degree of malnutrition, the extent of the disease, the degree of stress, and the ability to metabolize and use protein. Protein requirements are generally calculated using the actual body weight. A cancer patient may require approximately 1.5-2.5 g/kg/d.
Fluids: Fluid management ensures adequate hydration and electrolyte balance, and to prevent dehydration. Individual fluid needs may be affected by fever, edema, fistulas, chronic vomiting or diarrhea, impaired renal function, or the use of certain medications (such as diuretics). Signs and symptoms of dehydration include fatigue, acute weight loss, hypernatremia, poor skin turgor, dry oral mucosa, dark or strong smelling urine, and a decrease in urine output. A general guideline for estimating a patient’s fluid needs (without renal issues) is 30-35 ml/kg/d. Another quick estimation would be 1 ml per 1 calorie of estimated energy needs.