It has been known for several years that an abundant consumption of certain very specific fruits and vegetables reduces the risk of developing various types of cancer.
As a recent study reminds us, however, this protective effect is not associated with all plants and special attention must be paid to carefully choosing foods containing the greatest quantities of anti-cancer molecules.
Cancer is therefore not a disease that is mainly of hereditary origin, as is still too often believed, but a pathology closely linked to a set of factors related to lifestyle, especially smoking and obesity, the latter depending on our sedentary lifestyle and our eating habits. Several studies have shown a direct link between the regular consumption of certain plants and the reduction of the risk of developing certain types of cancer. The inclusion of these plants in the diet is particularly important, because not all fruits and vegetables have the same prevention potential.
There are significant differences in the levels of cancer-fighting compounds associated with these foods, and in a few cases, the phytochemicals that possess the strongest cancer-preventing activities are only present in specific fruits and vegetables. This is the case with isoflavones from soybeans, resveratrol from grapes, curcumin from the spice turmeric, isothiocyanates and indoles from broccoli or even catechins from green tea, the distribution of these anti-cancer molecules being extremely restricted in plants.
In other words, even if all fruits and vegetables are an integral part of a balanced diet, only some of them can really influence the risk of cancer.
Not just any fruit and vegetable
The importance of including these foods in the diet is well illustrated by the results of studies that examine the overall risk of cancer based on the total amount of fruits and vegetables, without taking into account the types of plants consumed.
For example, a study of more than 100,000 US healthcare professionals failed to find a beneficial link between total fruit and vegetable consumption and reduced cancer risk. However, a significant reduction in the risk of bladder cancer in men who consumed abundant cruciferous vegetables, as well as a significant reduction in the risk of prostate cancer following the regular consumption of tomato products were observed in this same population.
A European study of 400,000 people came to a similar conclusion, that is that the overall consumption of fruits and vegetables is not associated with a significant decrease in the risk of total cancer.
Here again, results previously obtained from this same population show that certain fruits (notably citrus fruits) considerably reduce the risk of stomach cancer. These observations therefore indicate that the development of different types of cancer is modulated differently by the plants in the diet and that it is not only necessary to take into account the quantity of total fruits and vegetables consumed by individuals, but also to take into account consider the nature of these foods.
Vegetables that do not protect health
These results are very important, half of the vegetables consumed are relatively devoid of protective effects (potatoes, lettuce and canned tomatoes) while the per capita consumption of vegetables rich in anticancer molecules, such as crucifers, barely reaches 1 %.
Increased consumption of foods containing high amounts of cancer-fighting molecules (cabbage and garlic families, green tea, berries, citrus fruits, tomato, carrot), capable of targeting several distinct processes essential for cancer cell growth, is therefore essential to achieve a significant reduction in the risk of certain cancers.
All fruits and vegetables are excellent for health in general and for the protection against cardiovascular disease, in particular. In the case of cancer, the protective effects are specific to certain fruits and vegetables, as we have repeatedly pointed out.
Hung HC et al. Fruit and vegetable intake and risk of major chronic disease. J Natl Cancer Inst,; 96:1577-84.
Michaud DS, Spiegelman D, Clinton SK, Rimm EB, Willett WC, Giovannucci EL. Fruit and vegetable intake and incidence of bladder cancer in a male prospective cohort. J Natl Cancer Inst, 91:605-13.
Giovannucci E et al. A prospective study of tomato products, lycopene, and prostate cancer risk. J Natl Cancer Inst, 94:391-98. Boffetta et al. Fruit and vegetable intake and overall cancer risk in the European Prospective Investigation into Cancer and nutrition (EPIC). J Natl Cancer Institute, 102:1-9
González CA et al. Fruit and vegetable intake and the risk of stomach and esophagus adenocarcinoma in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST). Int J Cancer, 118:2559-66.