An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

A prebiotic is "a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health." Today, only 2 dietary nondigestible oligosaccharides fulfill all the criteria for prebiotic classification. The daily dose of the prebiotic is not a determinant of the prebiotic effect, which is mainly influenced by the number of bifidobacteria/g in feces before supplementation of the diet with the prebiotic begins. The ingested prebiotic stimulates the whole indigenous population of bifidobacteria to growth, and the larger that population, the larger is the number of new bacterial cells appearing in feces. The "dose argument" is thus not supported by the scientific data: it is misleading for consumers and should not be allowed. A prebiotic index is proposed, defined as "the increase in the absolute number of bifidobacteria expressed divided by the daily dose of prebiotic ingested."

The inaugural meeting of the International Scientific Association for Probiotics and Prebiotics (ISAPP) was held May 3 to May 5 2002 in London, Ontario, Canada. A group of 63 academic and industrial scientists from around the world convened to discuss current issues in the science of probiotics and prebiotics. ISAPP is a non-profit organization comprised of international scientists whose intent is to strongly support and improve the levels of scientific integrity and due diligence associated with the study, use, and application of probiotics and prebiotics. In addition, ISAPP values its role in facilitating communication with the public and healthcare providers and among scientists in related fields on all topics pertinent to probiotics and prebiotics. It is anticipated that such efforts will lead to development of approaches and products that are optimally designed for the improvement of human and animal health and well being. This article is a summary of the discussions, conclusions, and recommendations made by 8 working groups convened during the first ISAPP workshop focusing on the topics of: definitions, intestinal flora, extra-intestinal sites, immune function, intestinal disease, cancer, genetics and genomics, and second generation prebiotics.

The authors express their appreciation to Dr. Barbara Schneeman, University of California, for her review of this manuscript and the opportunity for discussion of key points of the manuscript. Referee: Dr. Joanne Slavin, Food Science and Nutrition, University of Minnesota, 1334 Eckles Avenues, St. Paul, MN 5108 This critical review article examines the composition and source of inulin and oligofructose, the physiological effects of their consumption, and how these materials relate to the concept of dietary fiber. Inulin and oligofructose are fructans extracted on a commercial basis from the chicory root. Inulin has been defined as a polydisperse carbohydrate material consisting mainly, if not exclusively, of beta (2-1) fructosyl-fructose links ranging from 2 to 60 units long. Native chicory inulin has an average degree of polymerization (DP) of 10 to 20, whereas oligofructose contains chains of DP 2 to 10, with an average DP of 4. While a universally accepted definition for dietary fiber does not exist, it is generally agreed that this term includes saccharides (+lignin) that are not hydrolyzed or absorbed in the upper part of the gastrointestinal tract. These materials reach the colon, where they may be totally fermented, partially fermented, or remain unfermented. In addition, fibers contribute to fecal bulking. Inulin and oligofructose are not digested in the upper part of the gastrointestinal tract or are they absorbed and metabolized in the glycolytic pathway, or directly stored as glycogen like ‘sugars’ or starches. None of the molecules of fructose and glucose that form inulin and oligofructose appear in the portal blood. These materials are quantitatively fermented by the micro flora of the colon; further, it has been demonstrated that this fermentation leads to the selective stimulation of the growth of the bifidobacteria population. After reviewing their chemistry, origin, and physiological effects, it is the opinion of the authors that inulin and oligofructose are dietary fiber. They share the basic common characteristics of dietary fibers, that is, saccharides of plant origin, resistance to digestion and absorption in the small intestine, and fermentation in the colon to produce short-chain fatty acids that are absorbed and metabolized in various parts of the body. Moreover, this fermentation induces a bulking effect.

This critical review article examines the composition and source of inulin and oligofructose, the physiological effects of their consumption, and how these materials relate to the concept of dietary fiber. Inulin and oligofructose are fructans extracted on a commercial basis from the chicory root. Inulin has been defined as a polydisperse carbohydrate material consisting mainly, if not exclusively, of beta (2-1) fructosyl-fructose links ranging from 2 to 60 units long. Native chicory inulin has an average degree of polymerization (DP) of 10 to 20, whereas oligofructose contains chains of DP 2 to 10, with an average DP of 4.While a universally accepted definition for dietary fiber does not exist, it is generally agreed that this term includes saccharides (+ lignin) that are not hydrolyzed or absorbed in the upper part of the gastrointestinal tract. These materials reach the colon, where they may be totally fermented, partially fermented, or remain unfermented. In addition, fibers contribute to fecal bulking.Inulin and oligofructose are not digested in the upper part of the gastrointestinal tract or are they absorbed and metabolized in the glycolytic pathway, or directly stored as glycogen like 'sugars' or starches. None of the molecules of fructose and glucose that form inulin and oligofructose appear in the portal blood. These materials are quantitatively fermented by the microflora of the colon; further, it has been demonstrated that this fermentation leads to the selective stimulation of the growth of the bifidobacteria population.After reviewing their chemistry, origin, and physiological effects, it is the opinion of the authors that inulin and oligofructose are dietary fiber. They share the basic common characteristics of dietary fibers, that is, saccharides of plant origin, resistance to digestion and absorption in the small intestine, and fermentation in the colon to produce short-chain fatty acids that are absorbed and metabolized in various parts of the body. Moreover, this fermentation induces a bulking effect.

Dietary carbohydrates range in molecular size from simple sugars to complex polymers with a degree of polymerization (DP) of up to 100,000 or more. Oligosaccharides are generally defined as carbohydrates from 2 to 20 monomeric units long. Oligosaccharides have been dietary staples since antiquity but have received much less attention than other carbohydrates such as simple sugars or dietary fiber. Recently, interest in oligosaccharides has increased not only because of properties that include sweetening ability and fat replacement, but also because of resistance to digestion in the upper gastrointestinal tract and fermentation in the large bowel. Thus, some oligosaccharides have functional effects similar to soluble dietary fiber such as enhancement of a healthy gastrointestinal tract, improvement of glucose control, and modulation of the metabolism of triglycerides. These oligosaccharides are the nondigestible oligosaccharides. These compounds are easily incorporated into processed foods and hold much promise as functional ingredients in nutraceutical products.

The partial enzymatic hydrolysis of chicory inulin (GFn; 2 less than or equal to n less than or equal to 60) yields an oligofructose preparation that is composed of both GFn-type and Fn-type oligosaccharides (2 less than or equal to n less than or equal to 7; 2 less than or equal to m less than or equal to 7), where G is glucose, F is fructose, and n is the number of beta(2-->1) bound fructose moieties. Human studies have shown that feeding GFn-type oligomers significantly modifies the composition of the fecal microflora especially by increasing the number of bifidobacteria. The experiments reported here were used to test the hypothesis that the Fn-type molecules have the same property. During a controlled feeding study, 8 volunteers (5 females and 3 males) consumed 8 g/d of an Fn-rich product for up to 5 wk. Fecal samples were collected and analyzed for total anaerobes, bifidobacteria, lactobacilli, bacteroides, coliforms and Clostridium perfringens. Both 2 and 5 wk of oligofructose feeding resulted in a selective increase in bifidobacteria (P < 0.01). In addition, a daily intake of 8 g of the Fn-type oligofructose preparation reduced fecal pH and caused little intestinal discomfort.

Because anticarcinogenic and tumor-growth-inhibiting effects of nonsoluble fibers have been described, similar actions of soluble fibers appear to merit investigation. In a preliminary study on methylnitrosourea-induced mammary carcinogenesis in Sprague-Dawley female rats, 15% oligofructose added to the basal diet modulated this carcinogenesis in a negative manner. There was a lower number of tumor-bearing rats and a lower total number of mammary tumors in oligofructose-fed rats than in the group fed the basal diet alone. The effect of dietary nondigestible carbohydrates (15% oligofructose, inulin or pectin incorporated into the basal diet) on the growth of intramuscularly transplanted mouse tumors, belonging to two tumor lines (TLT and EMT6), was also investigated. The results were evaluated by regular tumor measurements with a vernier caliper. The mean tumor surface in the experimental groups was compared with that in animals of the control group fed the basal diet containing starch as the only carbohydrate. The growth of both tumor lines was significantly inhibited by supplementing the diet with nondigestible carbohydrates. Such nontoxic dietary treatment appears to be easy and risk free for patients, applicable as an adjuvant factor in the classical protocols of human cancer therapy.

Thank you for your comments on the ENDO consensus report that appeared in the British Journal of Nutrition recently (Goodlad & Wasan, 1999). We certainly agree with your general comment that such a report raises more questions than it gives answers. The question of the physiological function of short-chain fatty acids provides an example, and we certainly need more human trials based on sound and relevant hypotheses before we will be able to make scientifically sound recommendations. The ENDO consensus report (Van Loo et al. 1999) had a clear but limited objective and we disagree with the suggestion that it was ‘biased towards positive evidence’. Indeed, it reports on a consensus that was reached after 3 years of extensive scientific collaborative research and by reference to data, including human intervention studies, that were available at the time (and which have largely been confirmed more recently). Even if some of the consensual conclusions claim that a few effects of non-digestible oligosaccharides (NDO) are already supported by scientific data so as to justify ‘strong evidence’, most of our conclusions are prudent and remain on the ‘promising side’ or even the ‘preliminary side’ of the evidence. Your reference to the ‘unanticipated results of carotene, vitamins (C, E) or fibre studies’ is a little surprising. Indeed, the whole research strategy of the ENDO project has been to establish a sound scientific basis to enable the formulation of hypotheses that will justify human intervention studies likely to avoid such ‘surprising results’. Especially in the field of reduction of cancer risk, we report experimental data that, in our opinion, are preliminary but still can serve as the basis for planning further human trials to test likely hypotheses. We have made no claim for any anticancer effect in humans. In line with the concept of functional foods reported recently (Diplocket al. 1999), we support a prudent and stepwise approach to claims of enhanced function or disease risk. However, in our consensus meeting, we came to the conclusion that, especially in some areas (e.g. Ca bioavailability), scientific data are already indicative and promising enough to instigate (further) human trials without anticipating the conclusions of those studies. Further, it needs to be emphasized that NDO, particularly inulin and oligofructose, are present naturally in many of the food plants in current Western diets (Van Loo et al. 1995). NDO are non-toxic and are approved and widely-used safe food ingredients with a long history of human consumption. This, together with the potentially beneficial effects as observed in the experimental models, makes us feel comfortable in taking the position that we adopted in our paper, i.e. to promote further human nutrition studies with these compounds. Our consensus paper was intended to stimulate discussion and more research in a new and exciting field of nutrition, and your letter indicates that we have already succeeded. We look forward to more comments and new results.

Recent advances in biosciences support the hypothesis that diet modulates various body functions. Diet may maintain well-being and reduce the risk of some diseases. Such discoveries have led to the concept of ‘‘functional food’’ and the development of the new discipline, i.e., ‘‘functional food science.’’ A practical and simple definition of a ‘‘functional food’’ is a food for which a claim has been authorized . The food components to be discussed as potential ‘‘functional food ingredients’’ are the inulin-type fructans, i.e., chicory inulin and oligofuc-tose. The targets for their effects are the colonic microflora, the gastrointestinal physiology, the immune functions, the bioavailability of minerals, the metabolism of lipids and colonic carcinogenesis. Potential health benefits include reduction of risk of colonic diseases, noninsulin-dependent diabetes, obesity, osteoporosis and cancer. The documentation of such benefits requires scientific evidence that must be evaluated in terms of ‘‘health claims.’’ Previous assessments have concluded that, in terms of ‘‘functional claims,’’ strong evidence exists for a prebiotic effect and improved bowel habit. The evidence for calcium bioavailability is promising, and positive modulation of triglyceride metabolism is undergoing preliminary evaluation. Scientific research still must be done to support any ‘‘disease risk reduction claim,’’ but sound hypotheses do already exist for designing the relevant human nutrition trials. J. Nutr. 129: 1398S–1401S, 1999.

This paper assesses critically the science base that underpins the argument that oxidative damage is a significant causative factor in the development of human diseases and that antioxidants are capable of preventing or ameliorating these disease processes. The assessment has been carried out under a number of headings, and some recommendations for future research are made based on the present day knowledge base.

Fructan is a general term used for any carbohydrate in which one or more fructosyl-fructose link constitutes the majority of osidic bonds. This review focuses on the fate of inulin-type fructans (namely native chicory inulin, oligofructose produced by the partial enzymatic hydrolysis of chicory inulin, and synthetic fructans produced by enzymatic synthesis from sucrose) in the gastrointestinal tract, as well as on their systemic physiological effects on mineral absorption, carbohydrate and lipid metabolism, hormone balance, and nitrogen homeostasis. The scientific evidence for the functional claims of inulin-type fructans is discussed, as well as their potential application in risk reduction of disease, namely constipation, infectious diarrhea, cancer, osteoporosis, atherosclerotic cardiovascular disease, obesity, and non-insulin dependent diabetes.

Definitions, properties and reactions of radicals biologically relevant radicals biomolecular targets for radicals and reactive oxygen species pathology of radicals and reactive oxygen species antioxidants and radical scavengers - some therapeutic uses pharmacology of antioxidant molecules - analysis of their mechanisms of action.