Meta Analysis of Probiotics for Constipation

Jacob Collyer-Smith Lifestyle Writer

A new meta-analysis of probiotics (see Probiotics Learning Lab for more information) for constipation has been published in the American Journal of Clinical Nutrition. Constipation is a common condition which the NHS estimates to affect 1 in 7 adults and up to 1 in 3 children at any one time. Many standard treatments such laxatives and stool softeners may be effective in the short term but they are not recommended to take on a long-term basis.

Probiotics have long been touted as a possible long-term alternative for those suffering with constipation. A new meta-analysis carried out by researchers from King’s College London attempted to look at the current evidence to support the use of probiotics for constipation.

microscopic bacteria
B. lactis BB-12® under microscopic inspection

They analysed 14 randomised controlled (see Probiotics Learning Lab for more glossary terms) clinical trials to investigate the effect of probiotics on gut transit time, stool frequency and consistency, and other constipation symptoms. Their review revealed that probiotics significantly reduced gut transit time by over 12 hours, as well as increasing average stool frequency per week and improving the consistency of the stool.

No specific strains were mentioned in the meta-analysis but the researchers found that one specific species of probiotic, Bifidobacterium lactis, had a greater efficacy than others. The Bifidobacterium lactis species was more effective in all categories measured; gut transit time, stool frequency and consistency.

This is great news for constipation sufferers looking for a long-term alternative to standard over-the-counter treatments. Further research must be undertaken to find out what specific strains are the most effective in helping those with constipation, but research supporting the use of probiotics for constipation is mounting.

We recently wrote about similar research from Campinas State University in Brazil. Researchers there reported that a combination of prebiotics (see Probiotics Learning Lab) and two probiotic strains (L. acidophilus NCFM® and B. lactis HN019) were found to improve gut transit time and other constipation symptoms. 

Another notable trial, carried out by Matsumoto et al, observed the effects of B. lactis BB-12® in a group of healthy volunteers who suffered with constipation. The randomised controlled study found that supplementation with B. lactis BB-12® improved stool frequency and consistency.

For more detailed and up-to-date information on the subject, please take a look at our article 'Probiotics for Constipation'.


  1. Dimidi, E. et al (2014) The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition.
  2. Image source: