How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Probiotics
Living bacteria: each strain has its effects, and in healthy adults, they do not change the overall composition of the microbiota.
Benefits
- In irritable bowel syndrome, 5 months of a multi-strain blend reduced symptoms, including bloating and abdominal pain
- In elderly patients on antibiotics, fewer Clostridium difficile infections (pilot study)
- In healthy elderly people, 12 weeks of specific strains improved mental flexibility and reduced stress
- Taken by the mother during pregnancy and breastfeeding, reduced eczema in infants of allergic mothers
Precautions
Choose documented strains. Caution in case of severe immunodepression or serious illness: seek medical advice.
Recommended dosage
Around 10 billion CFU per day in the trial conducted on athletes; the dosage depends on the strains tested.
How to take it
- The strain matters: each trial tests specific strains (Lactobacillus rhamnosus GG, Bifidobacterium longum...), and the measured effects change from one trial to another.
- Dose: around 10 billion CFU per day in the trial conducted on trained athletes.
- How long: most trials last 8 to 14 weeks. The supplement's bacteria only stay in the gut temporarily.
- In healthy adults: no proof that they change the overall composition of the microbiota.
- During antibiotics: in a pilot study in elderly patients, a blend of Lactobacillus and Bifidobacterium reduced Clostridium difficile infections.
Did you know?
A systematic review has shown that, contrary to popular belief, probiotics do not alter the composition of the gut microbiota in healthy adults.
What the studies say
This systematic review and meta-analysis assessed the association between probiotic supplementation during pregnancy or early childhood and the prevention of asthma and wheezing in children. The results found no evidence to support a protective association between perinatal use of probiotics and a diagnosis of asthma or wheezing in children.
Azad MB, Coneys JG, Kozyrskyj AL, Field CJ, Ramsey CD, Becker AB, Friesen C, Abou-Setta AM, Zarychanski R. — BMJ (Clinical research ed.) (2013) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more