Susan Holmes, PhD, BSc, SRN, FRSH.
Director of Research and Development and Professor of Nursing, Faculty of Health, Canterbury Christ Church University College, Canterbury
People have believed for centuries that food is capable of both preventing and treating disease. This is true, at least to some extent, and it is clear that the nutrients food provides play vital roles in preventing and managing disease. In more recent history, there has been a move away from food towards drugs, which have been increasingly used to prevent, alleviate or treat disease. However, the discovery of nutrients, and the development of nutritional science, has led to an increasing recognition of the role of nutrition in maintaining health and, in turn, to the rise of so-called ‘healthy eating’ during the 1970s and 1980s. Continuing research has provided new evidence and a change in emphasis from the negative or harmful aspects of food towards the idea that food or its components may benefit health; this, in turn, has led to the development of a range of products known as ‘functional foods’ (Sheehy and Morrissey, 1998).
Although there is no universally accepted definition, functional foods generally refer to those believed to prevent or treat diseases (Goldberg, 1994). Although it can be argued that all food is ‘functional’, the modern concept is that such foods must provide benefits over and above the nutrients required for normal health. Thus Goldberg defined functional foods as ‘any food or food ingredient that has a positive effect on an individual’s health, physical performance or state of mind, in addition to its nutritive value’. Such components may include specific minerals, vitamins, fatty acids or dietary fibre and/or biologically active substances such as phytochemicals or other antioxidants and probiotics that contain live beneficial bacterial cultures (EUFIC, 2003).
The many physiological functions of the GIT, such as digestion and absorption, colonic fermentation, and gastrointestinal tract-associated immune activities, among many others (Robertfroid, 2002), make this the focus of much attention primarily due to the large number and variety of bacteria that live symbiotically with the host. Indeed, human adults carry over 1kg of bacteria in their gastrointestinal tract and excrete their own weight in bacteria every year (EUFIC, 2003). Robertfroid (2002) points out that such bacteria play a number of important physiological and/or metabolic roles (Box 1).
Although there are many definitions of probiotics, they can be simply described as ‘non-pathogenic micro-organisms that, when ingested, exert a positive influence in the health or physiology of the host’ (Marteau et al, 2002).
Since the value of probiotics remains to be proven, attention is increasingly turning to the use of prebiotics as a more certain way of securing potential benefits without associated difficulties (Rastall and Maitin, 2002). These, too, are treated as functional food ingredients and comprise complex oligosaccharides, such as dietary fibre, that are not digested by humans but are broken down in the gut by microbial action, thereby providing nutrients to promote the growth and colonisation of probiotic bacteria.
Probiotics are believed to hold promise for the future as they clearly allow modulation of the endogenous intestinal microflora and the immune system (Marteau et al, 2002).
Burns, A.J., Rowland, I.R. (2000) Anti-carcinogenicity of probiotics and prebiotics. Current Issues in Intestinal Microbiology 1: 1, 13-24.
Campieri, M., Gionchetti, P. (1999) Probiotics in inflammatory bowel disease: new insights to pathogenesis or a possible therapeutic alternative. Gastroenterology 116: 1246-1249.
CedgArd, L. (2002) Probiotics: The link between health and disease. Available at: www. positivehealth.com/permit/Articles/Environment/probiot.htm Accessed 22 May 2003.
Coconnier, M.H., Lievin, V., Hemery, E., Servin, A.L. (1998) Antagonistic activity against Helicobacter infection in vitro and in vivo by the human Lactobacillus acidophilus strain LB. Applied Environmental Microbiology 64: 4573-4580.
Cremonini, F., Canducci, F., Di Caro, S. et al. (1998) Helicobacter pylori treatment: a role for probiotics? Digestive Diseases 19: 2, 144-147.
Diplock, A.T., Aggett, P., Ashwell, M. et al. (1999) Scientific concepts of functional food science in Europe: consensus document. British Journal of Nutrition 81: (suppl 1), 1-28.
D’Souza, A.L., Rajkumar, C., Cooke, J., Bilpin, C.J. (2002)Probiotics in prevention of antibiotic associated diarrhoea. British Medical Journal 324: 1345-1346.
European Food Information Centre (EUFIC). (2003) Available at: www.eufic.org/en/quickfacts/functional_foods.htm (Accessed 22 May 2003).
Gorbach, S.L. (1990) Lactic acid bacteria and human health. Annals of Medicine 22: 37-41.
Goldberg, I. (1994) Introduction. In: Goldberg, I. (ed). Functional Foods: Designer foods, pharmafoods, nutraceuticals. London: Chapman and Hall.
Guarner, F., Schaafsma, G. (1998) Probiotics. International Journal of Food Microbiology 39: 237-238.
Guarner, F., Malagelada, J.R. (2003) Gut flora in health and disease. Lancet 361: 9356, 512-519.
Holzapfel, W.H., Haberer, P., Snel, J. et al. (1998) Overview of gut flora and probiotics. International Journal of Food Microbiology 41: 85-101.
Horie, H., Kanazawa, K., Okada, M. et al. (1999)Effects of intestinal bacteria on the development of colonic neoplasm: an experimental study. European Journal of Cancer Prevention 8: 237-245.
Intestinal Microecology Group, International Agency for Research on Cancer. (1977) Dietary fibre, transit time, fecal bacteria, steroids and colon cancer in two Scandinavian populations. Lancet 2: 207-211.
Isolauri, E., Arvola, T., Sutas, Y. (2000) Probiotics in the management of atopic eczema. Clinical and Experimental Allergy 30: 1604-1610.
Jonkers, D., Stockbrügger, R. (2003) Probiotics and inflammatory bowel disease. Journal of the Royal Society of Medicine 96: 4, 167-171.
Kalliomaki, M., Salminen, S., Arvolommi, H. et al. (2001) Probiotics in primary prevention of atopic disease: a randomised placebo-controlled trial. Lancet 357: 1078-1079.
Kampman, E., Giovannucci, E., van’t Veer, P. et al. (1994a) Calcium, vitamin D, dairy foods and the occurrence of colorectal adenomas among men and women in two prospective studies. American Journal of Epidemiology 139: 16-29.
Kampman, E., Goldbohm, R.A., van den Brandt, P.A., van’t Veer, P. (1994b) Fermented dairy products, calcium and colorectal cancer in the Netherlands cohort study. Cancer Research 54: 3186-3190.
Le, M.G., Moulton, L.H., Hill, C., Kramer, A. (1986) Consumption of dairy produce and alcohol in a case-control study of breast cancer. Journal of the National Cancer Institute 77: 633-636.
Marteau, P., Seksik, P., Jian, R. (2002) Probiotics and health: new facts and ideas. Current Opinion in Biotechnology 13: 5, 486-489.
Marteau, P.R., Vrese, M.D., Cellier, C.J., Schrezenmeir, J. (2001) Protection from gastro- intestinal diseases with the use of probiotics. American Journal of Clinical Nutrition 73: 4305.
Metchnikoff, E. (1907) The Prolongation of Life. London: Heinemann.
Moore, W.E., Moore, L.H. (1995) Intestinal floras of populations that have high risk of colon cancer. Applied Environmental Microbiology 62: 3202-3207.
Olah, A., Belagyi, T., Issokuta, A. et al. (2002)Randomized clinical trial of specific lactobacilli and fibre supplement to early enteral nutrition in patients with acute pancreatitis. British Journal of Surgery 89: 9, 1103-1107.
Peters, R.K., Pike, M.C., Garabrant, D., Mack, T.M. (1992) Diet and colon cancer in Los Angeles County, California. Cancer Causes Controls 3: 457-473.
Rafter, J. (2002) Lactic acid bacteria and cancer: mechanistic perspectives. British Journal of Nutrition 88: (suppl 1), S89-S94.
Rastall, R.A., Maitin, V. (2002) Prebiotics and synbiotics: towards the next generation. Current Opinions in Biotechnology 13: 5, 490-496.
Rayes, N., Seehoffer, D., Hansen, S. et al. (2002) Early enteral supply of lactobacillus and fiber versus selective bowel decontamination: a combined trial in liver transplant recipients. Transplantation 74: 1, 123-125.
Robertfroid, M., van Loo, J.A.E., Gibson, G.R. (1998) The bifidogenic nature of inulin and its hydrolysis products. Journal of Nutrition 128: 11-19.
Robertfroid, M. (2002) Foreword. British Journal of Nutrition 88: (suppl 1), S3-S4.
Scientific Concepts of Functional Foods in Europe Consensus Document. (1999) British Journal of Nutrition 81: 1, S1-S27.
Shanahan, F., McCarthy, J. (2000) Functional foods and probiotics: time for gastroenterologists to embrace the concept. Current Gastroenterology Reports 2: 345-346.
Sheehy, P.J.A., Morrissey, P.A. (1998) Functional foods: prospects and perspectives (Chapter 3). In: Henry, C.J.K., Heppell, N.J. (eds.). Nutritional Aspects of Food Processing and Ingredients. Gaithersberg, Md: Aspen.
Tuohy, K.M., Finlay, R.K., Wynne, A.G., Gibson, G.R. (2001a) A human volunteer study on the prebiotic effects of HP-inulin - gut bacteria enumerated using fluorescent in situ hybridisation (FISH). Anaerobe 7: 11-118.
Tuohy, K.M., Kolida, A., Lustenberger, A., Gibson, G.R. (2001b) The prebiotic effects of biscuits containing partially hydrolysed guar gum and fructooligosaccharides - a human volunteer study. British Journal of Nutrition 86: 241-348.
van’t Veer, P., Dekker, J.M., Lamers, J.W.J. (1989) Consumption of fermented milk products and breast cancer: a case-control study in the Netherlands. Cancer Research 49: 4020-4023.
Wollowski, I., Rechkemmer, G., Pool-Zobel, B.L. (2001) Protective role of probiotics and prebiotics in colon cancer. American Journal of Clinical Nutrition 73: S451-415.
Young, T.B., Wolf, D.A. (1988) Case-control study of proximal and distal colon cancer and diet in Wisconsin. International Journal of Cancer 42: 167-175.