Probiotics

Story

Connected to · 2

synergy · 1

IBS
Probiotic effects belong to strains, not to probiotics as a category. Ford 2018 pooled more than 50 trials in irritable bowel syndrome (IBS): some combinations or strains appear beneficial, but which ones work remains largely unclear. The ACG 2021 guideline therefore suggests against probiotics for global IBS symptoms (conditional recommendation, very low quality evidence).

contrast · 1

Gas and bloating
Bloating is one of the most common reasons people buy probiotics, but the American Gastroenterological Association's 2023 expert review advises explicitly that probiotics should not be used to treat bloating and abdominal distension; for lactose intolerance, a systematic review likewise found the evidence for probiotics insufficient.

Read full story

Stop 1/6

What counts as a probiotic

EVIDENCEGUIDE 3 · REVIEW 3 · RCT 1

READ THE ORIGINAL

Most bottles on the shelf that say contains probiotics do not actually earn the name.

A probiotic is a word with a threshold, and the threshold has four gates: the microbes must be alive, there must be enough of them, you must be able to say which strain it is, and that strain must have been tested in people for the very problem you want solved. Miss one gate and it is just a jar of ordinary bacterial powder.

The least intuitive gate is the strain. Different strains under the same species are like two strangers who share a surname: same name, completely different skills. Some can cling to the layer of mucus on the gut wall and some slide straight past; some can stand bile and some fall apart the moment they reach the small intestine. So a label that only says Lactobacillus has told you nothing. Before you buy, look on the bottle for the strain code (for example *Lactobacillus rhamnosus* GG, known as LGG). If you cannot find one, put it back.

A few groups should not buy them to take on their own: preterm infants, people who are critically ill or whose immune system is severely weakened, and anyone with a central venous line. In them, live bacteria can get into the blood. If fever or chills start while taking a probiotic, seek medical care immediately.

Educational content, not medical advice — consult a clinician.

Back

Probiotics

Story

Connected to · 2

synergy · 1

IBS
Probiotic effects belong to strains, not to probiotics as a category. Ford 2018 pooled more than 50 trials in irritable bowel syndrome (IBS): some combinations or strains appear beneficial, but which ones work remains largely unclear. The ACG 2021 guideline therefore suggests against probiotics for global IBS symptoms (conditional recommendation, very low quality evidence).

contrast · 1

Gas and bloating
Bloating is one of the most common reasons people buy probiotics, but the American Gastroenterological Association's 2023 expert review advises explicitly that probiotics should not be used to treat bloating and abdominal distension; for lactose intolerance, a systematic review likewise found the evidence for probiotics insufficient.

Read full story

Stop 1/6

What counts as a probiotic

EVIDENCEGUIDE 3 · REVIEW 3 · RCT 1

READ THE ORIGINAL

Most bottles on the shelf that say contains probiotics do not actually earn the name.

A probiotic is a word with a threshold, and the threshold has four gates: the microbes must be alive, there must be enough of them, you must be able to say which strain it is, and that strain must have been tested in people for the very problem you want solved. Miss one gate and it is just a jar of ordinary bacterial powder.

The least intuitive gate is the strain. Different strains under the same species are like two strangers who share a surname: same name, completely different skills. Some can cling to the layer of mucus on the gut wall and some slide straight past; some can stand bile and some fall apart the moment they reach the small intestine. So a label that only says Lactobacillus has told you nothing. Before you buy, look on the bottle for the strain code (for example *Lactobacillus rhamnosus* GG, known as LGG). If you cannot find one, put it back.

A few groups should not buy them to take on their own: preterm infants, people who are critically ill or whose immune system is severely weakened, and anyone with a central venous line. In them, live bacteria can get into the blood. If fever or chills start while taking a probiotic, seek medical care immediately.

Educational content, not medical advice — consult a clinician.