It has been postulated that 80 percent of cancers may be due to environmental factors, and among them dietary factors may be of much more importance. For example, a strong positive correlation has been worked out between cancer of colon and dietary intake of fat. Similarly, a positive correlation between consumption of dietary fat and breast cancer has been noticed. However, a number of studies indicated that consumption of dietary fibre, may protect aginst intestinal carcinogens or precursors by dilutional or through other effects. Although the available epidemiological data with regard to prevent cancer through foods, are not entirely consistent yet a few evidences generally support that use of certain foods protect against some of the cancers.  

CANCER PREVENTING FOODS
1. Foods having carotenoids and lycopene: Red peppers have great cancer fighting properties, which are owing to the presence of carotenoids present in them. Carrots are one of the richest sources of beta carotene, a potent oxidant that helps to fight potentially harmful free radicals. A high intake of beta carotene (orange in colour) has been shown to reduce the rate of postmenopausal breast cancer by about 20 percent. Beta carotene is also present in other food stuffs like sweet potatoes, pumpkins and mangoes. Some green leaf vegetables such as spinach and fenugreek are also rich in beta carotene. Apricot, peaches and pumpkin are full of beta carotene (a form of vitamin), which protects our body from cancer. Lycopene present in tomatoes is an antioxidant, which helps in preventing free radicals, responsible for causing cancer. Lycopene is also found in watermelons, guava, papaya and grapes.
2. Foods having starch: Starchy foods especially potatoes contain loads of beta carotene, which has a cancer fighting property. Boiled potatoes are very effective in preventing prostrate cancer.
3. Protein rich foods: Soya milk contains plant chemicals called phytoestrogens, which block the damaging effects of the female oestrogen in the breast tissue. Too much oestrogen can trigger cell division, which can lead to breast cancer. Consumption of curds everyday can reduce the risk of breast cancer. The acidophilus in curds stimulates the body's production of gamma interferon a chemical that can slow down the growth of tumours. Mushrooms rich in proteins can also help to beat cancer. Many chemotherapy drugs currently in use have been derived from natural substances found in plants so it is not too far fetched to think that mushrooms could be a valuable source of potential new cancer drugs.
4. Foods having indoles and sulphoraphane: Broccoli has cancer-fighting compounds known as indoles. Indoles help to deactivate and dispose off excess oestrogen. High consumption can decrease the risk of cancer by 40 per cent. Cauliflower is rich in sulphoraphane which is a cancer fighting chemical. Cauliflower is also rich in fibre which helps to maintain regular bowl movements. It can also eliminate toxins from the body.
5. Foods having omega fatty acids: Olive oil is helpful in preventing cancer. It actually contains monosaturated omega-9 fatty acid which is helpful in suppressing the growth of breast cancer. An American survey found that women who consume olive oil atleast twice a day have 25 per cent lower risk of breast cancer.
6. Ginger in relation to ovarian cancer: Ovarian cancer has been reported to be a cause of death of 16,000 women out of 22,000 in USA every year. Hence, researchers from the University of Michigan Comprehensive Cancer Centre conducted a study on ginger, using cells in a lab dish and found that ginger powder solution killed the ovarian cancerous cells (Anonymous, 2006).
7. Selenium rich foods: Selenium is a mineral, not an oxidant nutrient, but it is a component of an antioxidant enzymes. Rice and wheat are the major sources of selenium. There is very little selenium in fruits and vegetables.
8. Lutein rich foods: It is best known for its association with healthy beautiful eyes, is abundant in green leaf vegetables such as spinach and also present in egg yolk. Lutein, an important antioxidant which works to reduce the amount of free radicals in the body.
9. Vitamin A rich foods: Vitamin A is found in three forms such as vitamin A1, vitamin A2 and vitamin A3. Foods rich in vitamin A include sweet potato, carrots, milk, egg yolk.
10. Vitamin C rich foods: It is abundant in many citrus fruits such as orange, grapes, strawberry, Indian gooseberry (amla) etc.
11. Vitamin E rich foods: Vitamin E is found in almonds and in many oils including wheat gram, safflower, corn, soyabean oil and also in nuts, mangoes, broccoli, etc. All the above said vitamins act as antioxidants which are often described as "mopping up" free radicals, meaning they neutralize the electrical charge and prevent the free radicals from taking electrons from other molecules.
12. Potassium, magnesium, niacin, caffeine rich drink: Laboratory based basic research had suggested that coffee which was once perceived as unhealthy is indeed capable of removing harmful entities and preventing various types of cancer (Anonymous, 2007) including tobacco induced carcinogenesis, pancreatic cancer and alcohol related liver cirrhosis as said by radiation biologist Dr. P.C. Kesavan, who was also former Director, Biomedical Group in Bhaba Atomic Research Centre. Laboratory based basic research suggested that the substances in coffee (potassium, magnesium, caffeine, chlorogenic acid and other phenolic compounds) benefit glucose and insulin metabolism. All these substances effectively remove harmful hydroxyl radicals and electrons.
13. Flavonone, phenyl propanoids, hydrobenzoic acid and conjugated fatty acid rich juice: The researchers have identified all these active groups of ingredients in pomegranate juice which had a molecular impact on cell adhesioin and migration in metastatic prostate cancer cells (Anonymous, 2010).
14. Protective enzyme rich food: Eating plenty of seasonal fruits like raspberries and others help in reducing the risk of cancer (Anonymous, 2007). In a study, 20 patients ate an ounce and half of freeze dried black raspberries daily for 26 weeks, had a marked decline in the isoprostane, reflecting less oxidative stress. The researchers also looked at tissue levels of an enzyme called GSTpi, which helps detoxify carcinogens. They found that 37 per cent of patients had an increase in this protective enzyme which helps in fighting cancer.
In fact, the research suggested that black raspberries are good for warding off oesophageal cancer and raw vegetables like broccoli for preventing bladder cancer.
*Ex-Associate Dean-cum-Chief Scientist, Krishi Vigyan Kendra, SKUAST-J. C/o 258-C, Sainik Colony, Jammu-180011 (J&K).
** MBBS (Gold Medallist), MS (PGI Chandigarh), DNB, FICO and Advanced ICO (UK), FAICO (All India Award Winner).