Probiotics, prebiotics and antioxidants as functional foods*
Włodzimierz Grajek, Anna Olejnik and Anna Sip
Department of Biotechnology and Food Microbiology, August Cieszkowski Agricultural University of Poznan, Poznań, Poland; ½e-mail: [email protected]
The term “functional foods” comprises some bacterial strains and products of plant and animal origin containing physiologically active compounds beneficial for human health and reducing the risk of chronic diseases. Among the best known functional compounds probiotics, prebiotics and natural antioxidants should be given as examples. These substances can be obtained by biotechnological methods and by extraction from plant or animal tissues.
Keywords: probiotics, prebiotics, antioxidants, functional food
Within the last decade, we have observed distinct changes in the understanding of the role of foods in human health promotion. The first frontier of scientific investigations has moved from the primary role of food as the source of energy and body-forming substances to the more subtle action of biologically active food components on human health. In the industrialized world, there has been an explosion of consumer interest in the active role of foods in the well-being and life prolongation as well as in the prevention of initiation, promotion and development of cancer, cardiovascular diseases and osteoporosis. As a result, a new term — functional food — was proposed (Berner & O’Donnell, 1998; Dimer & Gibson, 1998; Sanders, 1998; Diplock et al., 1999; Pisulewski & Kostogrys, 2003).
According to the definition, functional food is a part of an everyday diet and is demonstrated to offer health benefits and to reduce the risk of chronic disease beyond the widely accepted nutritional effects. The term ‘functional foods’ was introduced in Japan in mid 1980s. This type of foods is known on the Japanese market as “Foods for Specified Health Use” (FOSHU). The functional foods comprise: (i) conventional foods containing naturally occurring bioactive substances (e.g., dietary fiber), (ii) foods enriched with bioactive substances (e.g., probiotics, antioxidants), and (iii) synthesized food ingredients introduced to traditional foods (e.g., prebiotics). Among the functional components, probiotics and prebiotics, soluble fiber, omega-3 – polyunsaturated fatty acids, conjugated linoleic acid, plant antioxidants, vitamins and minerals, some proteins, peptides and amino acids, as well as phospholipids are frequently mentioned. These active substances constitute a focus of contemporary science of human nutrition. A wide range of food products offer a variety of physiologically active compounds; functional food should be understood as a new idea, rather than a defined product. It should be also stressed that functional foods are not pills or capsules but are consumed as part of a normal everyday diet. Epidemiological studies and randomized clinical trials carried out in different countries have demonstrated or at least suggested numerous health effects related to functional food consumption, such as reduction of cancer risk, improvement of heart health, stimulation of immune system, decrease of menopause symptoms, improvement of gastrointestinal health, maintenance of urinary tract health, anti-inflammatory effects, reduction of blood pressure, maintenance of vision, antibacterial and antiviral activities, reduction of osteoporosis and antiobese effects. These effects can be claimed on food product labels, a practice more and more commonly introduced for the promotion of functional foods in the food market.
At the moment, the most important and the most frequently used functional food compounds are probiotics, prebiotics, plant antioxidants, vitamins and calcium. It has been given high priority in the production of probiotics and prebiotics, and the extraction of bioactive components from plant materials by enzyme and fermentation technology to reduce loss of these compounds as well as by genetic engineering to intensify their biosynthesis. At the present time, biotechnology plays a key role in the functional food industry. However, transgenic foods are not well accepted in the European Union and food industry companies prefer to employ methods of conventional biotechnology.
Source: Acta Biochimica Polonica Vol. 52 No. 3/2005, 665–671