Article written by :
Senior Executive Dietitian
Post Graduate Diploma in Dietetics and applied Nutrition (J.U.)
Cancer is a term used to refer malignant neoplasms or tumors. It is caused by mutation or abnormal activation of cellular genes that control cell growth and cell mitosis. Cancer is considered to be one of the leading causes of morbidity and mortality worldwide.
Two factors that are invariably involved in the etiology of cancer are genes and environment. Various factors inducing synergy are-
- Ionising radiation.
- Chemical substances, e.g. asbestos, benzene.
- Dietary factors.
- Hormones, viruses also act as co-factors in the development of some malignant diseases.
- Nitrosamines present in tobacco.
Nutrition in the etiology of cancer
Scientific evidence suggests that one-third of the cancer deaths that occur each year can be attributed to nutrition and lifestyle behaviour such as poor diet, physical inactivity, overweight and obesity, alcohol use and the rest is related to use of tobacco.
Diet contains both inhibitors and enhancers of carcinogenesis. Examples of dietary carcinogen inhibitors include antioxidants (Vitamin C, E) and phytochemical(anthrocyanins, lycopene). Dietary enhancers of carcinogenesis may be the fat in red meat or the polycyclic aromatic hydrocarbons that form with grilling of meat at high heat.
Certain relations are the following:
Experimental and epidemiologic data show a link between some cancers and the amount of fat in the diet. Diet high in fat content is associated with increased risk of cancer of colon and rectum, oesophagus, gall bladder, breast among post-menopausal women, endometrium, pancreas and kidney.
Diet high in protein is generally low in fibre content. Increased red meat intake (i.e. beef, pork, lamb) has been found to be associated with an enhanced risk of colon and prostate cancer.
SOY AND PHYTOESTROGENS
Soy is a plant-based protein and it contains phytoestrogens(eg –weak plant based estrogens and compounds such as isoflavones and lignans). A soy containing diet may be protective against breast cancer.
High fibre foods such as whole grains comprise an important part of healthy diet. Early studies focused on the possible protective role of fibres in safe-guarding against cancer of colon, rectum, breast and ovaries.
Studies indicate that alcohol consumption is associated with increased risk of oral cancer, pharynx, larynx, oesophagus, lung, colon, rectum, liver and breast.
Cancer and Malnutrition
Almost all patients suffering from cancer are at risk of malnutrition, so nutritional screening is of utmost importance. Common oncological therapies viz, chemotherapy, radiation, immunotherapy and surgery are key contributors in promoting deterioration in nutritional status. A steady fall in food consumption, resulting from mucositis, xerostomia, food aversions, in contrast to a sudden surge in energy requirement is the primary reason behind increasing trend of weight loss.
A common secondary diagnosis in patients with advanced cancer is termed as cancer cachexia, which is characterized by progressive weight loss, anorexia, generalised weakness, immunosupression, altered basal metabolic rate and abnormalities in fluid and energy metabolism.
Whether newly diagnosed, undergoing active therapy, recovering from treatment, or in remission and trying to prevent cancer recurrence, nutrition is an important component of cancer care and management. Energy, Protein, Fluid and Micronutrient requirements have been summed below:
Calorie density sufficient to counter catabolic or hypermetabolic states and to support necessary anabolism is necessary. Presence of fever or infections, anti-cancer therapies, intent of treatment (curative, control or palliation) should be taken into consideration. A patient may require 3000-4000 kcal depending on degree of malnutrition and body trauma.
To maintain healthy immune system protein requirement varies from 1.2-1.6gm/kg ideal body weight (for hyper-catabolic cancer patients) to 1.5-2.5 gm / kg ideal body weight (for severely stressed patients).
Proper fluid management is required to ensure the maintenance of adequate hydration, tissue perfusion and electrolyte balance.
The use of multivitamin and mineral supplements that provides no more than 100% of dietary reference intakes is generally considered safe.
PHYTOCHEMICALS AS ANTI-CANCER AGENTS
Dark yellow, orange , deep green vegetables, onion, garlic, tomatoes, cruciferous vegetables provide an array of phytochemicals like carotenoids, flavonoids, lignans, isoflavones which can be achieved and optimally utilised by having a proper balanced diet.
Controversy over whether the use of antioxidant supplements such as vitamins, A, C, E, zinc, selenium is effective or not is still in vogue.
Individualized or personalized nutritional counselling is the first line of treatment in malnourished patients. Last but not the least it is important to take care of the mental health of the patients. Most of the terminally ill patients suffer from severe depression which is detrimental. It is necessary to boost up their confidence. Both nutrition therapy and medicines, along with proper counselling can help patient achieve a proper mental and physical well-being.