Also called · lactic acid bacteria · Lactobacillus · Bifidobacterium · synbiotics · postbiotics
What it is
Lactic acid bacteria is a catch-all for bacteria that ferment sugar into lactic acid. Producing lactic acid does not make a bacterium good — E. coli belongs to the group too.
The subset that survives in the gut and does something useful is what gets called probiotics.
Prebiotics are their food (soluble fibre), synbiotics are the two combined, and postbiotics are killed cultures, leaving only the metabolites and cell bodies.
Bacterial names narrow from genus to species to strain. Distinctive properties are decided at the strain level, which is why WHO, FAO and IPA all tell you to check for a strain designation.
What it does
They cannot change the composition
Gut flora settle into a composition shortly after birth and do not shift much for life. Firmicutes, Bacteroidetes and Fusobacteria make up roughly 95% of it; Actinobacteria, the phylum Bifidobacterium belongs to, is barely 1%. However much you add, you are not displacing the incumbents.
What they leave behind is short-chain fatty acids
Ingested probiotics survive anywhere from 20 minutes to two weeks. When their run is over they leave in the stool. The real effect is the short-chain fatty acids they produce while passing through, and the change those make to the gut environment.
Which is why order matters
Feed the beneficial bacteria you already have with plenty of soluble fibre first; add probiotics on top when immunity looks like it needs the help. That is the right sequence.
How to feed it
It varies by strain and formulation, so follow the label. In Korea, 19 species are approved for use in health functional foods.
Feeding it consistently matters more than when. Thirty minutes after a meal gastric acid production picks up and kills the bacteria, so before or during a meal is better. If you give it before food, mixing it into something with fat in it — pet milk rather than water — improves survival.
What to watch for
Bacteria that run out of food start eating the mucus coat lining the gut to survive. As that layer thins and breaches, harmful bacteria and food particles get through — which is where allergy and, at the extreme, sepsis come from.
Most synbiotic products on the market contain a very thin amount of prebiotic. What is in the product is used up before it ever reaches the gut.
Common questions
Which strain comes before how many. Distinctive properties are decided at the strain level, and any product built on a good strain will name it.
They store easily and deliver metabolites directly, so the effect can come faster — but they are dead cultures, so they cannot keep working in the gut or raise the population of beneficial bacteria.
Concerns this ingredient relates to
General nutrition information. It does not replace a diagnosis or a prescription. If your animal has a medical condition or is on medication, talk to your veterinarian first.