Fruit, Vegetables & Cancer
Despite the fact that no causality can be found that any single food is capable of causing cancer, there is a great deal of evidence that certain types of food protect against cancer. As a generic food group fruit and vegetables should be eaten at least five times a day. Whilst many American and European doctors recommend five, they do so because they feel that five is a manageable number, yet eight is more realistic and some doctors even recommend eight vegetables and three fruits.
However, whatever the number of fruit and vegetables that should be eaten a day, most of the cancer studies seem to agree that the level or incidence of cancer is low when the intake of fruit and vegetables is high in a society. Equally important is the fact that there is no recorded study any where in the world that has blamed a single case of cancer on a fruit or a vegetable.
Initially it was thought that the antioxidant effect was responsible for the protection that fruit and vegetables seem to confer on vegetarians. The antioxidant nutrients in fruits and vegetables prevent oxidative damage to the cells and DNA by free radicals, and they prevent the initiation of damage that starts the cancer in the first place.
There is a strong suggestion that these nutrients also protect the lipids which are present in the cellular membranes, and may contribute to the stabilization of cells. Also they may have a wide variety of chemical components that play a very active part in the overall protection against cancer, but research into this area is relatively new. The promotion of certain types of food that have been called super foods has arisen because of a marketing technique, rather than science. The growth of the use of food to promote health and reduce the risk of disease has led to the rapid development of food that possesses these capabilities.
Blueberries and bilberries or Vaccinium myrtillus, contains anthocyanin. These nutrients make up the dark blue purple color and they are found in many foods of a similar color. Nutrients in bilberry, protect against free radical damage and they also prevent damage from certain toxins especially potassium bromate, a fairly common food additive. Bilberry can protect against damage from radiation and it strengthens the capillaries.
However, bilberries or any other berry is not a super food and no amount of eating bilberries will give more protection than eating a wide range of fruit and vegetables. Even if you eat a kilo of bilberries it is still only one fruit from a nutrition point of view. In general increasing the amount of unprocessed food such as fruit and vegetables, wholegrain cereals nuts and seeds will confer a greater health benefit than concentrating on the miracle qualities of Tropical rain forest berries.
There is moderately strong evidence that stomach and colorectal cancers occur less in communities that routinely eat over 500g of fruit and vegetables a day. There is less strong evidence that the same levels of fruit and vegetables protect against esophagus breast and lung cancers. There is a possible preventative factor in the case of prostrate, pancreatic, bladder and cervical cancers.