Cancer and nutritional needs
Apart from a poor appetite and loss of weight, some people with cancer have other difficulties eating. Some of these problems may relate to the cancer itself, some relate to medications, the treatment and its side effects. Due to the body’s response to tumours the way the body uses nutrients is sometimes changed in people with cancer.
Tumours may produce chemicals that change the way the body uses certain nutrients or absorb nutrients from food. The body's use of protein, carbohydrates, and fat may be affected, especially by tumours of the stomach or intestines. Therefore, often sick people may appear to be eating enough, but the body may not be able to absorb all the nutrients from the food.
In the majority of cases, treatment of cancer involves therapies that destroy cancer cells growing in the body. The most common treatments, used alone or in combination, are surgery, chemotherapy, radiotherapy, hormone therapy, and immunotherapy (or biological therapy). Although all of these methods are very powerful in the process of killing the cancer cells, some healthy cells are also damaged, especially those normally growing and dividing rapidly, such as those in the mouth, digestive tract, and hair. This is what causes side effects of cancer treatment, and this in turn can affect nutritional needs. The nature, severity and degree of side effects will vary from person to person and rely on many factors including the type of cancer you have, the part of your body being treated, the type and length of treatment, and the dose of treatment. Side effects can often be well-controlled and most of them go away after treatment ends.
Some side effects of cancer therapy can further affect eating habits: dietary problems already present may be aggravated; nausea and sickness can cause loss of appetite and taste alterations can make certain foods less appealing. As a result, cancer patients may eat less and may have trouble consuming enough of a wide variety of foods to satisfy nutritional needs.
Eating too little protein and calories is the most common nutrition problem facing many cancer patients. Protein and calories are important for healing, fighting infection and providing energy. Other deficiencies experienced by cancer patients are vitamins (Folate, Vitamin A, Vitamin C, and Vitamin D) and minerals (Copper, Iron, Magnesium, Zinc, and Calcium).
Source: Nutrition in cancer Editorial Board
