Naughty Boy Pro-B

Live bacterial cultures· evidence: Limited

These products contain live bacteria, usually Lactobacillus, Bifidobacterium and Streptococcus strains, counted in colony-forming units (CFU). Effects in studies depend on the exact strain and dose, so results for one strain cannot be assumed for another, and a higher CFU count is not proof of a better product.

Many trials have been run, but they are mixed and often small, and most look at specific groups of people rather than healthy adults. In healthy people, there is little good evidence that taking live cultures every day makes a noticeable difference. There are no authorised health claims for live cultures in Great Britain, so we make no claims about what they do.

If you want to try them, choose a product that names its strains (with strain codes) and gives the count at the end of shelf life, and give it about four weeks.

Typical dose: Products typically provide 1 to 50 billion CFU a day; check the strain list and whether the count is guaranteed to the end of shelf life.

Safety: Generally well tolerated; some people notice wind or bloating at first. Speak to your doctor before use if you have a weakened immune system (for example during chemotherapy or after a transplant), a central line, are seriously ill, or are buying for a premature baby.

Research we looked at:
NHS. Probiotics. nhs.uk (health A to Z).
NCCIH. Probiotics: what you need to know. National Institutes of Health.
Hill C et al. (2014). The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology 11:506-514.