Dr. Elhadi M. Yahia, February 2009.
Increasing incidences of some chronic diseases, including cancer and cardiovascular disease, especially in industrial countries, have raised a lot of awareness in the last few years regarding the importance of diet. It is estimated that one third of the cancer cases and up to half of cardiovascular disease rates are thought to be diet related. Many studies have shown mounting evidence that people who avoid fruit and vegetables completely, or consume very little, are indeed at increased risk of these diseases. Therefore, interest in the health benefits of fruit and vegetable consumption is increasing, fruit and vegetable consumption in many countries has increased, and therefore fruit and vegetable production has certainly increased.
Fruits and vegetables have historically been considered rich sources of some essential dietary micronutrients, some vitamins, and fibers, and more recently they have been recognized as important sources for a wide array of many other phytochemicals that individually, or in combination, may benefit health, and therefore some people had conferred on fruits and vegetables the status of “functional foods”. There are many biologically plausible reasons for this potentially protective association, including the fact that many of the phytochemicals act as antioxidants.
Phytochemicals present in fruits and vegetables are many and very diverse (more than 8000). Naturally occurring compounds such, as phytochemicals, which possess anticarcinogenic and other beneficial properties, are referred to as chemopreventers. One of the predominant mechanisms of their protective action is due to their antioxidant activity and the capacity to scavenge free radicals. Consumption of fruit and vegetable diet has shown to increase antioxidant concentration in blood and body tissues, and potentially protects against oxidative damage to cells and tissues, and therefore can protect from diverse illnesses. Many epidemiological evidences indicate that avoidance of smoking, increased consumption of fruits and vegetables, and control of infections can have a major effect on reducing rates of several chronic diseases including cardiovascular disease and different types of cancer. However, phytochemicals in fruits and vegetables also act in several other ways, other than been antioxidants. Among the most investigated chemopreventers are some vitamins, plant polyphenols, and pigments such as carotenoids, chlorophylls, flavonoids, and betalains.
Evidences indicate that for the effect of fruit and vegetable consumption on health, the whole may be much more important than the sum of the parts, meaning that individual components (phytochemicals) appear to act synergistically where the influence of at least some of these is additive. Therefore, in many instances some isolated compounds from fruits and vegetables do not work as the consumption of whole fruits and vegetables.
Therefore, it is argued that increasing intake (400 to 800 g/day) of fruits and vegetables is a public health strategy of considerable importance for individuals and communities worldwide. For this reason the World Health Organization (WHO), and several international and national health and nutrition organizations recommend daily intake of 400 g of fruits and vegetables or more per person (the National Institute of Nutrition in Mexico recommends 500g/person/day). Many of the putative chemoprotective phytochemicals in fruits and vegetables are colored (due to different pigments), and therefore the guidelines are sometimes based on selecting one serving daily of fruits and vegetables from each of 7 color classes (red, yellow-green, red-purple, orange, orange-yellow, green, white-green), so that a variety of phytochemicals is consumed. Many studies have shown that consumption of fruit and vegetables is still low in many countries, and efforts are still needed to increase it.
Therefore, there are many accumulating evidences that consumption of fruits and vegetables is important for human health, and that’s why medical authorities all over the world are recommending it. However, will the current world economic difficulties effect these efforts? It is very difficult to predict. Almost all fruits and vegetables are produced in Developing Countries, mostly to export to Developed Countries. Will the trend of consumption in Developed Countries be affected, and therefore affecting the amount produced and exported of these important food commodities? Unfortunately i suspect it will, although especially not being an economist, I hope I am wrong. Any views from better experts?