Health benefits of probiotics: are mixtures more effective than single strains?

PURPOSE: Most studies on probiotics utilise single strains, sometimes incorporated into yoghurts. There are fewer studies on efficacy of mixtures of probiotic strains. This review examines the evidence that (a) probiotic mixtures are beneficial for a range of health-related outcomes and (b) mixtures are more or less effective than their component strains administered separately. RESULTS: Mixtures of probiotics had beneficial effects on the end points including irritable bowel syndrome and gut function, diarrhoea, atopic disease, immune function and respiratory tract infections, gut microbiota modulation, inflammatory bowel disease and treatment of Helicobacter pylori infection. However, only 16 studies compared the effect of a mixture with that of its component strains separately, although in 12 cases (75%), the mixture was more effective. CONCLUSION: Probiotic mixtures appear to be effective against a wide range of end points. Based on a limited number of studies, multi-strain probiotics appear to show greater efficacy than single strains, including strains that are components of the mixtures themselves. However, whether this is due to synergistic interactions between strains or a consequence of the higher probiotic dose used in some studies is at present unclear.

Health benefits of probiotics: are mixtures more effective than single strains?

Probiotic mixtures appear to be effective against a wide range of end points. Based on a limited number of studies, multi-strain probiotics appear to show greater efficacy than single strains, including strains that are components of the mixtures themselves. However, whether this is due to synergistic interactions between strains or a consequence of the higher probiotic dose used in some studies is at present unclear.

The cyclical behaviour of sector and regional diversification benefits: 1987-2002

This paper investigates the time series behaviour of the relative benefits of sector and regional diversification strategies, using the notion of cross-sectional dispersion introduced by Solnik and Roulet (2000). Using monthly data over the period 1987:1 to 2002:12, four sector and four regional classifications are examined in the UK. The results indicate that sector and regional dispersion indices are highly time varying and so dwarf any lower frequency cyclical components that may be present. Nonetheless, periods of high dispersion are closely followed by periods of low dispersion, suggestive of cyclical behaviour of sector and regional diversification benefits. Then, using the HP-filter we isolated the cyclical component of the various dispersion indices and found that the sector dispersion indices are generally above the regional dispersion indices. This implies that a sector diversification strategy is likely to offer greater risk reduction benefits than a regional diversification approach. Nonetheless, we find that in some periods, certain regional diversification strategies are of equal or greater benefit than certain sector approaches. The results also appear to be quite sensitive to the classifications of sectors and regions. Hence, the appropriate definition of sectors and regions can have important implications for sector and regional diversification strategies.