Choosing the right probiotic increases chance of benefit

JIM IS ON HIS WAY home from the hygienist, who told him he has mild gingivitis (gum inflammation), which is causing him to have bad breath. He has stopped by to see if there is a probiotic or supplement he can take to help manage his symptoms.

Most sources attribute the discovery of probiotics in 1907 to Élie Metchnikoff, a Russian scientist and Nobel Prize winner of the Pasteur Institute in Paris. He narrowed down the reason villagers in the Caucasus Mountains of Bulgaria were more likely than anyone else in the area to live past 100 to their daily practice of drinking a fermented yoghurt drink, which later investigation revealed contained the probiotic Lactobacillus bulgaricus.¹

Although this discovery was only last century, human use of fermented foods, such as beer, cider, kafir, kimchi, miso, sauerkraut and yoghurt, spans thousands of years. However, not all fermented foods are probiotics because to be a probiotic, the food must contain live microorganisms at the time of consumption – some fermented foods, such as sourdough, are baked before being eaten, which kills the bacteria.²

Probiotic is a Latin word meaning “for life”, but WHO defines probiotics as “live microorganisms which when administered in adequate amounts, confer a health benefit on the host”.

Technically, controlled human trials are required before a product or food can be termed a probiotic, although this rule is not always followed commercially because they are considered dietary substances, which lack the regulatory requirements medicines do. There is also a concern laboratory-produced bacteria may not maintain their properties when grown on an industrial scale.³

Research has mostly concluded that probiotics are not for everyone, although evidence suggests certain probiotics have beneficial effects in some conditions, but these are strain specific.⁴

Probiotics are not as easy to make as they sound, and there are several challenges with growing probiotics on an industrial scale. Although most probiotics belong to the food categories “generally recognised as safe” (GRAS) or “qualified presumption of safety” (QPS), it is during the manufacturing process that issues can arise. These include factors such as genetic variation between generations of bacteria during the growing phases, free radical damage affecting probiotic stability, contaminants and the viability of the probiotic at the end of the process.³

Probiotic potency is measured in colony-forming units (CFUs), which are the usual number of colonies expected per dose. Because probiotics are a living organism, they will degrade with time. A product that states the CFUs at the end of shelf life (EOSL or expiry date) may be preferred over a product that states the CFUs at the time of product release because there is no way of telling how many CFUs remain when the customer buys the product.⁵

Always stock products from a reputable manufacturer with good and transparent quality control practices.

Diarrhoea, abdominal cramping, bloating and gas are common side efects reported with probiotics, which may cause people to stop taking them

Generally, probiotics are considered safe, but they are not harmless, and documented and theoretical side effects do exist.^5,6

Populations vulnerable to serious probiotic side effects (eg, sepsis) include those with a weakened immune system, with an intravenous catheter in place or with a severe infection, and premature infants. Cross-contamination of opened probiotic supplements by harmful bacteria in a hospital setting leading to serious infection has also been reported.^3,5

See the “Probiotics and Prebiotics” chapter of the Healthcare Handbook 2023–2025 for questions to ask your customers to determine who you should refer to the pharmacist.⁵

Diarrhoea, abdominal cramping, bloating and gas are common side effects reported with probiotics, which may cause some people to stop taking them.^4,5

There is no one cure-all probiotic. Probiotics are organised according to their family group (genus), species and strain, although often the strain is not specified (although it does matter).⁴ For example: genus Lactobacillus; species rhamnosus; strain GG. Note that the genus is shortened to its first letter (eg, L. rhamnosus GG) when repeated in a text.

Seven core probiotic genera are in general use: Bacillus, Bifidobacterium, Enterococcus, Escherichia, Lactobacillus, Saccharomyces, Streptococcus. All are bacteria except for Saccharomyces, which is a yeast (a member of the fungus kingdom).^3,4,7

When selecting a probiotic for a customer, make sure you ask what condition they want to take it for, then recommend a probiotic species/strain that has good evidence of benefit for that condition (see table).^3,4

Recommendations for your customers should include the caveats that probiotics need to be taken daily and for up to two weeks before showing any beneficial effect, and to stop taking them if they experience any intolerable side effects.

It is interesting to note that despite a clear correlation between gut microbiota health (beyond the scope of this article), the skin and the brain (called the gut–skin–brain axis), research has not yet established a clear benefit of consumed probiotics and immune system health.^3,4,7

YOU TELL JIM that there is some evidence for the use of S. salivarius K12 probiotics to reduce bacterial growth in the mouth, although they are not a substitute for good oral hygiene, which includes proper teeth brushing and daily flossing or interdental brush use. He is keen to try them, so you sell him a kit to help repopulate his mouth with healthy bacteria, and a new toothbrush to help with his dental regimen.

This case study is hypothetical and does not represent a living, identifiable person