Phytochemicals enhanced levels

In the same manner, the use of genetic manipulation to optimize levels of nutrients and phytochemicals will provide many members of society with a dilemma. Scientists, food producers, and regulators must make every effort to enter into a dialogue with consumers to explain the benefits and risks associated with these new products. Ultimately the consumer alone will determine how successful an improved, phytochemically enhanced food product will be. Experience has shown that the concerns and distrust of consumers over one genetically manipulated foodstuff may, however unscientific, be extended to all. 

One important area that demands further study relates to the ability of plant scientists and agronomists to modify the composition of fruits and vegetables to enhance levels of phytochemicals or to introduce relevant genes into other species in order to broaden the occurrence of these compounds in the diet, as presented in Chapter 6, on sulforaphane. In this area, as in many others, the public s attitude to future genetically manipulated plants and foods will be cmcial. 

Echinacea has been used for centuries as a medicinal plant. Research from the last two decades shows that Echinacea can enhance the immune system when in vitro and in vivo indicators are used in the model investigations. Further investigations, e.g., bioavailability and clinical studies, are needed to thoroughly understand the immune-enhancing activity of Echinacea. In addition, further research is needed to characterize processing methods that do not significantly reduce the levels of phytochemicals. 

Examples of phytochemicals and their biological effects include isothiocyanates and sulforaphane which are found in vegetables such as broccoli and have been shown to trigger enzyme systems that block or suppress cellular DNA damage and reduce tumor size in animal studies (4) Allylic sulfides, found in onions and garlic, can enhance immune function, increase the production of enzymes that help to excrete carcinogens, decrease the proliferation of tumor cells, and reduce serum cholesterol levels (5). Isoflavonoids in soy have also been shown to reduce serum cholesterol levels in humans (6). 

Unlike the situation for conventional nutrients such as vitamins and minerals, where the role in disease prevention and recommended levels are both understood, the situation for phytochemicals remains obscure. Crucial decisions need to be made as to which secondary metabolites, individual or group, should be manipulated, to what level(s), in which crops to facilitate optimum nutritional and health benefits. Given that attempts to increase, for example, brassica consumption generally founder on the rock of well-established food preferences, would it be better to enhance sulforaphane levels in brassicas or to introduce the relevant genes and controls into other, more widely consumed species Of course, one option does not exclude the other. 

The mere enhancement of phytochemical levels is not an answer in itself Such higher levels may not be effectively absorbed and may pass through the body and be excreted without any biological benefit. Again, it must be remembered that the improved plants must first be consumed if their benefits are to be achieved. Many phytochemicals. 

The levels and bioavailability of phytochemicals in plant foods such as legumes, cereals, vegetables, herbs and fraits can be greatly affected by processing such as fermentation. This subsequently leads to increased antioxidant properties, which may be benehcial for treatment and/or prevention of diseases such as atherosclerosis and cancer. Thus fermentation, especially with probiotics (functional microbes), can serve as an important process not only for preservation but also for production of functional foods with enhanced bioactive and antioxidant properties. 

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