A recent study suggesting that fruits and vegetables are inefficient when it comes to preventing cancer ignores one important fact: certain specific vegetables do, in fact, have cancer-fighting potential.
Keep in mind that 70 per cent of cancers can be prevented by making simple modification to our lifestyle, including having a proper diet, which in turn will help reduce the rate of obesity.
Numerous studies have indicated that, with the exception of lung cancer which is predominately caused by smoking, the primary cancers that affect people in western countries (breast, prostate and colon) have a much lower incidence rate in Asian countries.
For example, a person from India or Thailand has about a 25 per cent less risk of developing prostate or colon cancer than a person who lives in the west, while the risk of developing breast cancer is between 10 per cent and 25 per cent less for a person living in Bangkok or Tokyo compared to a person living in Ontario.
These huge differences are not the result of a genetic advantage, because Asians that move west see their risk of contracting these cancers rise to similar rates of the people living here. Lifestyle really does have a significant influence on the risk of developing certain cancers.
The importance of a healthy lifestyle was clearly demonstrated in 1981 when Richard Doll and Richard Peto showed that between 75 per cent and 80 per cent of all cancers diagnosed in the United States in 1970 could have been prevented by simple modifications to aspects of one's lifestyle, particularly related to smoking and diet.
One of the primary goals of the study was to identify the food items that contain the highest anticancer activity and, thanks to numerous advances made since then, a direct link between the regular consumption of certain vegetable species and the risk of developing cancer was established.
Current statistics show that cancer-fighting ability is not evenly distributed amongst all fruit and vegetables and that only certain types, notably vegetables from the crucifer family (cabbage, broccoli, cauliflower, etc), green tea and items rich in carotenoids like tomatoes and carrots are capable of strong preventative action, with an associated 25 per cent to 75 per cent reduction in the risk of certain types of cancer.
At the risk of being repetitive, it is for this reason that studies examining the total impact of fruits and vegetables on the global incidence rate of cancer fails to prove that a protective effect exists. This is because anti-cancerous foods represent only a fraction of consumed fruits and vegetables, and their positive impact on the risk of developing certain cancers is masked by the predominance of vegetables that lack these protective characteristics.
Even if a person consumes five portions of fruits and vegetables every day, this type of healthy eating habit still won't have a major impact on the risk of developing cancer if the foods being consumed aren't loaded with protective properties.
For example, if a minimum of three portions of crucifer vegetables per week is needed to reduce the risk of prostate cancer, the consumption of three portions of other non-protective foods, like potatoes, lettuce or bananas, will have no impact on this risk. Therefore, it is possible to eat the same quantity of vegetables while producing completely different protective effects.
In other words, the prevention of cancer through diet does not only mean we should be eating plenty of fruits and vegetables, but rather that we should be consuming large quantities of specific foods, those that contain the highest quantities of these anti-cancerous compounds.