Nutrition plays an important role in the treatment and prevention of cancer. Nutrients provide essential nourishment to the body for maintenance of life whereas the nutritional deficiencies can induce premature ageing and suppress immunity of the body causing cancer. The nutrients can be divided into two groups, which include Energy nutrients and Protector nutrients. The vitamins & minerals (such as B vitamins and magnesium), which help in the process of “conversion of food into energy” by activating enzymes, are known as energy nutrients, while the nutrients (such as beta-carotene, vitamin C, vitamin E, Copper, Manganese, Selenium and Zinc), which protect the body against environmental pollutants, toxins and radiation, etc. are called protector nutrients. Most of the protector nutrients act as antioxidants by eliminating the free radicals (highly reactive, unstable molecules that promote cancer growth) that are produced during the process of conversion of food into energy. Nutrients perform specific functions in the body; for example, vitamin C, vitamin E and Selenium protect the body against environmental pollutants, while B vitamins counteract the emotional & physical stress.
Vegetarian diet is rich in fibre, micronutrients and antioxidants. A study conducted on 1200 persons, above the age of 66 years, has shown that the vegetarians have significantly lower incidence of cancer as compared to the non-vegetarians. Another study conducted at the Institute for Experimental Pathology, German Cancer Research Center, Heidelberg, Germany has shown that the blood samples of vegetarians contain higher levels of cancer preventing factors such as Carotene and Glutamine transferase. Moreover, the activity of Natural Killer cells (NK cells) is twofold higher in vegetarians as compared to the non-vegetarians.
Amino acids play an important role in the treatment and prevention of cancer. L-arginine enhances the anticancer activity of Natural Killer cells (NK cells), Cytotoxic T Lymphocytes (CTL) and other immune cells. N-acetyl cysteine is a sulphur-containing amino acid, which plays an important role in the synthesis of DNA, inhibits angiogenesis, enhances immunity of the body and reduces toxic effects of radiotherapy & chemotherapy. N-acetyl cysteine is a precursor of Glutathione that protects DNA from the damaging effects of free radicals. Another sulphur-containing amino acid known as Methionine increases the survival period in liver cancer patients.
Coenzyme Q10 (Ubiquinone) is found in soya bean, grape seed, sesame seed, pistachio, walnut and spinach. Coenzyme Q10 along with beta-Carotene, vitamin E and Selenium protects the tissues of liver, kidney and heart from free radicals. Coenzyme Q10 prevents the genesis of cancer by enhancing the activity of macrophages. A study conducted on the advanced cases of breast cancer has shown complete regression of the tumour after administration of Coenzyme Q10.
Gamma linolenic acid (GLA) is found in black currant oil, evening primrose oil and the mother’s milk. Gamma linolenic acid inhibits the growth of cancer by producing good eicosanoids (PGE-1). This function of GLA is promoted by vitamin B3, vitamin B6, vitamin C and Zinc. Studies have shown that combination of GLA and vitamin C increases survival period in liver cancer patients.
Beta-carotene is a precursor of vitamin A. It is found in carrot, sweet potato, spinach, most of the vegetables and yellow coloured fruits. Beta-carotene increases immunity of the body against cancer by enhancing activity of the Natural Killer cells (NK cells). It also acts as an antioxidant. Beta-carotene protects the body against many cancers, including those of the cervix, lung and stomach.
Vitamin A is known to enhance the activity of immune cells in the body against cancer. Clinical studies have shown significant regression of tumour in the patients of squamous cell carcinoma of the lung after administration of vitamin A for 15 months. Vitamin A also protects the body against malignant melanoma. A derivative of vitamin A, called 13-cis-retinoic acid has shown good results in squamous cell carcinoma occurring in the head & neck.
Vitamin B3 or Niacin (Nicotinic acid) is found in asparagus, whole grain and brewer’s yeast. Studies have shown that vitamin B3 is effective in the treatment of cancer in doses of 50 mg daily. Vitamin B3 also enhances the therapeutic effects of radiotherapy & chemotherapy.
Vitamin B6 is found in bananas, apples, carrots, sweet potatoes and leafy green vegetables. Vitamin B6 enhances immunity of the body. It also protects the respiratory tract from environmental pollutants and infections by keeping mucous membrane in a healthy state. Vitamin B6 is known to inhibit growth of various cancers, including cancers of the liver and cervix. It also protects against side effects of radiotherapy. Studies conducted on 33 patients of bladder cancer have shown considerably decreased incidence of recurrence after administration of vitamin B6.
Vitamin C is found in many fruits and vegetables, particularly citrus fruit, broccoli and green pepper. Vitamin C enhances immunity of the body by boosting the production of interferon and stimulating the Natural Killer cells (NK cells). It inhibits the growth of cancer by decreasing the production of Nitrosamines. Vitamin C protects the body from the toxic effects of chemotherapy & radiotherapy. Studies done in Scotland and Canada have shown that vitamin C prolongs the survival period and improves the quality of life in the terminal cases of cancer. Vitamin C prevents the direct spread of cancer by stabilising and strengthening connective tissues around the site of cancer.
Vitamin D and its metabolites prevent the growth of cancer by inhibiting angiogenesis (formation of new blood vessels). It promotes apoptosis (programmed cell death) in the cancerous cells. Vitamin D induces conversion of the cancerous cells into normal cells. Research done in Australia has revealed that vitamin D protects the body against cancer of the prostate. The incidence of prostate cancer is found to be higher in northern areas (Iceland, Denmark and Sweden) due to the limited natural sunlight.
Vitamin E is found in dark green leafy vegetables, wheatgrass and unrefined vegetable oils. It protects the body from various carcinogens due to its strong antioxidant and detoxifying activities. A study done on the patients of oral leukoplakia has shown recovery in 46 per cent cases after administration of vitamin E (in doses of 400 IU twice daily) for 24 weeks. Vitamin E protects the body against many cancers, especially colon cancer. It also reduces the toxic side effects of chemotherapy & radiotherapy.
Folic acid is found in cabbage, dark green leafy vegetables, citrus fruits and dairy products. It plays an important role in the synthesis of DNA. Folic acid protects the body against many cancers, especially cervical cancer.
Broccoli prevents the genesis of cancer due to its rich content of vitamin C. It protects the body against cancer of the colon due to its high contents of fibre & calcium. Broccoli protects against cervical cancer due to its high content of foliate. It also protects the body against cancer of the lung due to its high content of beta-carotene.
Omega-3 fatty acids are found in fish and plant oils (flaxseed, pumpkin seed, corn, safflower, sunflower and walnut). These play an important role in the normal functioning of cells. Omega-3 fatty acids protect the body against cancer by inhibiting the production of bad eicosanoids (such as PGE-2). Omega-3 fatty acids protect the body against cancers of the breast and liver. Omega-3 fatty acids enhance the therapeutic effect of chemotherapy & radiotherapy by altering the cell membrane of cancerous cells. Omega-3 fatty acids should be consumed in a moderate quantity and that too along with adequate amounts of antioxidants, because the excessive consumption of any type of fat can enhance the risk of cancer.
Genistein and Diadzein are natural phyto-oestrogens found in soybean and other legumes. Genistein and Diadzein inhibit the growth of hormone dependent cancers by blocking the action of oestrogen. Studies have revealed that Genistein prevents mutations in some specific oncogenes. It also possesses antioxidant activity.
Limonene is found in essential oils of citrus fruits and spices. Limonene and one of its derivatives, called Perillyl alcohol are found to arrest the tumour growth. Limonene also enhances the process of detoxification in the liver.
Fibre found in green vegetables, fruits and whole grain protects the body against cancer by eliminating toxins from the digestive tract. Inositol hexaphosphate is found in the high fibre diet such as legumes, cereals, grains and citrus fruits. Studies conducted by Fred Hutchinson Cancer Research Centre in Seattle, Washington have shown that Inositol hexaphosphate possesses anticancer activity.
Lactobacilli normally found in the human intestines are friendly bacteria, which protect the body against cancer by detoxifying chemical carcinogens and due to their direct anticancer activity. Lactobacilli produce B vitamins, which enhance immunity of the body. A study done on 138 patients of bladder cancer has shown much lower incidence of recurrence after administration of Lactobacilli. Another study conducted on 100 patients of the advanced stage cancer has shown prolonged survival and better quality of life after administration of Lactobacillus bulgaricus.
Selenium is a trace mineral, which is found in fruits and vegetables. Selenium is essential in the synthesis of an enzyme called Glutathione, which plays an important role in the detoxification process of the body. Selenium also enhances activity of the Natural Killer cells (NK cells) and arrests micrometastases. Selenium protects the body against cancer by stimulating DNA repair enzymes. Data collected from 17 countries have shown that low intake of Selenium in diet can lead to the genesis of leukaemia and many other cancers including those of the colon, rectum, prostate, ovary, breast and lung. A study done in Finland has shown that the persons having serum selenium levels less than 45 mcg per litre are three times more likely to develop cancer than those having the serum selenium levels above 45 mcg per litre. According to a report published in the Biological Trace Element Research in 1991, the scientists at Chinese Academy of Medical Sciences Cancer Institute in Beijing have found that the incidence of liver cancer (in members of those families who have high incidence of liver cancer) was considerably lowered after administration of Selenium in doses of 200 mcg daily for 2 years.
Copper is a trace element that is required for proper functioning of immune cells in the body. Copper is an essential co-factor in the synthesis of an important group of enzymes, known as Cuproenzymes, which protect the body against cancer.
Zinc is found in onion, grains, soybean and sunflower. It is essential in the synthesis of DNA. Zinc protects the body against many cancers, especially cancer of the prostate by enhancing the activity of immune cells. Zinc has an antagonistic relationship with copper, i.e. the excess of one causes the deficiency of another.
Germanium is a trace element that increases the availability of oxygen to cells. Germanium inhibits the growth of cancer because the cancerous cells cannot survive under oxygen rich conditions. A study conducted in Japan on the inoperable cases of small-cell lung cancer has shown prolonged survival period and fewer side effects after administration of Germanium along with chemotherapy & radiotherapy.
Molybdenum is a trace element that is required by the body in small amounts (150-500 mcg daily) for detoxification of alcohols, aldehydes, sulphites and copper-containing compounds. Molybdenum protects the body against various cancers, especially oesophageal cancer.
Chromium is essential in the synthesis of Glucose tolerance factor (GTF). Chromium protects the body against cancer by regulating the blood sugar level and improving the immune functions. The prolonged consumption of refined food (such as white sugar and white flour), which are extremely poor in chromium can lead to hyperglycaemia (increased level of glucose in the blood) that induces carcinogenesis by promoting synthesis of bad eicosanoid (such as PGE-2).
Potassium protects the body against cancer as it plays an important role in repairing the damaged DNA. A study done in China has shown that high potassium and low sodium intake partially reverses the DNA damage.
Iodine found in the iodised salt and seafood is required for proper metabolism and growth of the body. Iodine plays an important role in repairing various tissues of the body. It protects the body against many cancers, especially breast cancer.
Manganese is a cofactor in the synthesis of many enzymes. One of the major antioxidant enzymes, known as Superoxide dismutase contains manganese. It protects the body against cancer. Manganese also counteracts the immuno-suppressive effect of the stress hormone (Cortisol).
Magnesium is found in nuts, grains, brown rice and green vegetables. It helps to maintain pH balance in the blood and other tissues of the body. Magnesium plays an important role in the synthesis of DNA. It protects the body against cancer.
Calcium is found in nuts, dark green vegetables and milk products. Calcium protects the body against cancer of the colon. Calcium should be taken along with magnesium because the latter helps the absorption of calcium.