1. Br J Nutr. 2010 Aug;104 Suppl 2:S1-63.

Prebiotic effects: metabolic and health benefits.

Roberfroid M, Gibson GR, Hoyles L, McCartney AL, Rastall R, Rowland I, Wolvers D,
Watzl B, Szajewska H, Stahl B, Guarner F, Respondek F, Whelan K, Coxam V, Davicco
MJ, Léotoing L, Wittrant Y, Delzenne NM, Cani PD, Neyrinck AM, Meheust A.

Université Catholique de Louvain, Brussels, Belgium.

The different compartments of the gastrointestinal tract are inhabited by
populations of micro-organisms. By far the most important predominant populations
are in the colon where a true symbiosis with the host exists that is a key for
well-being and health. For such a microbiota, 'normobiosis' characterises a
composition of the gut 'ecosystem' in which micro-organisms with potential health
benefits predominate in number over potentially harmful ones, in contrast to
'dysbiosis', in which one or a few potentially harmful micro-organisms are
dominant, thus creating a disease-prone situation. The present document has been 
written by a group of both academic and industry experts (in the ILSI Europe
Prebiotic Expert Group and Prebiotic Task Force, respectively). It does not aim
to propose a new definition of a prebiotic nor to identify which food products
are classified as prebiotic but rather to validate and expand the original idea
of the prebiotic concept (that can be translated in 'prebiotic effects'), defined
as: 'The selective stimulation of growth and/or activity(ies) of one or a limited
number of microbial genus(era)/species in the gut microbiota that confer(s)
health benefits to the host.' Thanks to the methodological and fundamental
research of microbiologists, immense progress has very recently been made in our 
understanding of the gut microbiota. A large number of human intervention studies
have been performed that have demonstrated that dietary consumption of certain
food products can result in statistically significant changes in the composition 
of the gut microbiota in line with the prebiotic concept. Thus the prebiotic
effect is now a well-established scientific fact. The more data are accumulating,
the more it will be recognised that such changes in the microbiota's composition,
especially increase in bifidobacteria, can be regarded as a marker of intestinal 
health. The review is divided in chapters that cover the major areas of nutrition
research where a prebiotic effect has tentatively been investigated for potential
health benefits. The prebiotic effect has been shown to associate with modulation
of biomarkers and activity(ies) of the immune system. Confirming the studies in
adults, it has been demonstrated that, in infant nutrition, the prebiotic effect 
includes a significant change of gut microbiota composition, especially an
increase of faecal concentrations of bifidobacteria. This concomitantly improves 
stool quality (pH, SCFA, frequency and consistency), reduces the risk of
gastroenteritis and infections, improves general well-being and reduces the
incidence of allergic symptoms such as atopic eczema. Changes in the gut
microbiota composition are classically considered as one of the many factors
involved in the pathogenesis of either inflammatory bowel disease or irritable
bowel syndrome. The use of particular food products with a prebiotic effect has
thus been tested in clinical trials with the objective to improve the clinical
activity and well-being of patients with such disorders. Promising beneficial
effects have been demonstrated in some preliminary studies, including changes in 
gut microbiota composition (especially increase in bifidobacteria concentration).
Often associated with toxic load and/or miscellaneous risk factors, colon cancer 
is another pathology for which a possible role of gut microbiota composition has 
been hypothesised. Numerous experimental studies have reported reduction in
incidence of tumours and cancers after feeding specific food products with a
prebiotic effect. Some of these studies (including one human trial) have also
reported that, in such conditions, gut microbiota composition was modified
(especially due to increased concentration of bifidobacteria). Dietary intake of 
particular food products with a prebiotic effect has been shown, especially in
adolescents, but also tentatively in postmenopausal women, to increase Ca
absorption as well as bone Ca accretion and bone mineral density. Recent data,
both from experimental models and from human studies, support the beneficial
effects of particular food products with prebiotic properties on energy
homaeostasis, satiety regulation and body weight gain. Together, with data in
obese animals and patients, these studies support the hypothesis that gut
microbiota composition (especially the number of bifidobacteria) may contribute
to modulate metabolic processes associated with syndrome X, especially obesity
and diabetes type 2. It is plausible, even though not exclusive, that these
effects are linked to the microbiota-induced changes and it is feasible to
conclude that their mechanisms fit into the prebiotic effect. However, the role
of such changes in these health benefits remains to be definitively proven. As a 
result of the research activity that followed the publication of the prebiotic
concept 15 years ago, it has become clear that products that cause a selective
modification in the gut microbiota's composition and/or activity(ies) and thus
strengthens normobiosis could either induce beneficial physiological effects in
the colon and also in extra-intestinal compartments or contribute towards
reducing the risk of dysbiosis and associated intestinal and systemic
pathologies.


PMID: 20920376 [PubMed - indexed for MEDLINE]