That’s the view of international expert Dr Lynne McFarland, from the University of Seattle, who delivered a keynote address at our Probiota Asia summit in Singapore.
Dr McFarland, who has over 150 peer-reviews articles to her name, said there were pros and cons when considering if single or multi-strain options were preferable.
While the former are not subject to any other strain interference, have inherent stability, and come with clearly defined risks / drug interactions, the latter could benefit from more mechanisms of action and synergies, although it is harder to define risks and interactions.
During her presentation, she referenced published studies to compare clinical efficacy of single-strain versus multi-strain mixtures.
With regard to the prevention of antibiotic-associated diarrhoea, she said the single strain S. boulardii effectively prevents the illness in both paediatric and adult patients.
However, some mixtures (L. rhamnosus R11 and L. helveticus R52) were found to be are more effective in preventing the illness, but only in children and not adults.
She added that several other single strains and mixtures lacked RCTs for both sub-populations.
When it comes to eradicating Helicobacter pylori, Dr McFarland argued that both single and multi-strains showed significant benefits.
The single strain S. boulardii leads to a 0.66 day reduction of diarrhoea, while the two strain mixture L. rhamnosus R11 and L. helveticus R52 led to a 0.41 day reduction.
“These are both significan reductions, in my opinion,” she added.
However, mixes of two Lactobacilli strains, and S. boulardii and Bifido longum had only been assessed in one trial each, meaning no conclusions could be made.
Dr McFarland added: “Surprisingly, adding more strains does not result in significantly higher efficacy in all diseases, but the benefits of multi-strain mixtures may include broader range of effects and more mechanisms of action because the synergy between strains in a mixture may be important.
“Building a rational mixture should be based on efficacy for single strains, then the effect of adding additional strains, but is clear that more research is needed.”