EFFECTS OF PROBIOTICS AND PREBIOTICS ON BLOOD-LIPIDS

Since the early work of Mann and Spoerry, probiotics in the form of fe rmented milk products have been reputed to have cholesterol-lowering p roperties in humans. However, studies conducted since the early 1970s have produced equivocal findings, with interpretation of the outcomes complicated by use of excessive quantities of product, inadequate samp le sizes, failure to control nutrient intake and energy expenditure an d variations in baseline blood lipids. More recent studies are of bett er quality, but fail to provide convincing evidence that 'live' fermen ted milk products have cholesterol-lowering efficacy in man. Future st udies using probiotics should ensure adequate sample sizes sufficient to detect relatively small changes in blood cholesterol and should be conducted over longer periods of time. The recent introduction of the concept of prebiotics has directed attention towards the possibility t hat alterations in gut microflora induced by the fermentation of non-d igestible components of the diet may also have the potential to influe nce systemic lipid metabolism. This possibility has been strengthened by the observation that in animals, dietary oligofructosaccharides cau se suppression of hepatic triglyceride and VLDL synthesis, resulting i n marked reductions in triglyceride, and to a lesser extent cholestero l, levels. Evidence for similar effects in humans is sparse and more s tudies are needed, particularly with respect to effects on postprandia l triglyceride concentrations.