The amounts of health promoting compounds in fruit and vegetable products vary so much that the possible beneficial health effects from these products is far from optimal.
Simulations done by researchers at Wageningen University predict about a 45% reduction in the risk of colon cancer (2700 cases per year in the Netherlands) if the entire food production chain can see to it that the average quality of healthy substances in fruit and vegetable products increases by a factor of 3.
Furthermore, the same products also have to vary much less with regard to the amount of health beneficial substances than the more than hundredfold differences which are currently found among products.
The health benefit seems realisable through the selection of fruit and vegetable varieties, the optimisation of industrial and domestic treatments and the provision of good consumer information, according to the researchers Matthijs Dekker an Ruud Verkerk from the Product Design and Quality Management Group at Wageningen University, The Netherlands.
The Wageningen researchers analysed the entire production chain--from "farm to fork" --of both fresh vegetables and fruits as well as processed products such as juices and ready-to-eat meals. In their research, Dekker and Verkerk have mapped out what happens to levels of important health promoting components such as glucosinolates.
According to the researchers, the breeding, cultivation, storage and processing of fruits and vegetables have always been aimed at maximizing production, minimizing loss from spoilage, and maintaining an attractive appearance of the fruits and vegetables for the consumer. Fruits and vegetables, however, contain important components for human health such as vitamins and minerals. In the last years, it has also become clear that more plant substances, so called phytochemicals, such as flavonoids, carotenoids, and glucosinolates play an important protective role against all kinds of diseases related to ageing, such as cancer, and cardiovascular diseases.
Numerous epidemiological studies on the relationship between the consumption of fruits and vegetables and diseases related to ageing, in which data of, at times, thousands of people have been processed, turn out to be rather variable. In these studies, beneficial effects have been found but the effects also show large variation and strongly differ between studies. The enormous variation in the amounts of protective components in the consumed form of fruits and vegetables are a possible explanation for the variable results of the epidemiological health researchers'.
Laboratory research into the effect of the health benefits of the various components from the fruits and vegetables shows much clearer effects. Also, animal experiments and human intervention studies give much more unequivocal effects. In these studies various phytochemicals show protective effects on DNA damage, which are linked to ageing diseases, as well as protective effects by increased levels of detoxifying enzyme systems in the body.
Several steps and choices in the food production chain determine the amount of healthy substances in the final product: the chosen fruit and vegetable varieties, the conditions of cultivation and post-harvest conditions of storage and processing, both industrially and in the consumer's kitchen. The variation is not visible to the consumer because these products do not have the amounts of these materials on their label.