Facts
- Having a healthy gut (balance between good and bad bacteria) can protect against disease.
- Good gut health improves immunity, appetite, and metabolism.
- Changes in diet, antibiotic use, age and infection can contribute to disease including inflammatory bowel disease, colorectal cancer, obesity and type 2 diabetes.
- Use of probiotics to improve gut health is becoming increasingly popular.
- Current research does not strongly support the use of probiotics to improve gut health.
Common perceptions on probiotics
The gut microbiota (microorganisms including bacteria, virus and fungi that reside in the gut) can influence diseases ranging from obesity, type 2 diabetes, inflammatory bowel disease, colorectal cancer, depression, dementia, MS and Parkinson’s disease among others.
Probiotics from pro and biota, meaning "for life", are defined as “live microorganisms which when administered in adequate amounts confer a health benefit on the host”.
Probiotics can be taken as a dietary supplement or naturally in foods like yoghurt, kombucha, kefir and sauerkraut, which are fermented with beneficial bacteria. Probiotics may contain a variety of microorganisms. The most common are bacteria that belong to groups called Lactobacillus and Bifidobacterium.
Different types of probiotics may have different effects on health.
Probiotics must be kept alive to be active. They can be killed by heat, stomach acid, or just die over time. This has introduced concerns about feasibility of using probiotics for health benefit.
Nonetheless, the use of probiotic supplements has become increasingly popular over the past decade. It is estimated to be acclaim a US$37 billion market worldwide.
Despite widespread use of probiotics, recent evidence also suggests varying results in terms of safety and effectiveness at restoring gut microbes to improve health.
In detail
Individual results may vary given the gut microbiota is different in different individuals.
Meaning that an individual’s response to prebiotics can vary between individuals. This is in terms of its effectiveness in improving gut diversity, restoring gut microbes and improving health.
Some individuals may have beneficial effects whilst others may reject the probiotic. Meaning no or little beneficial effect is observed.
The use of probiotics after antibiotics is common practice for many people. However, research shows that probiotics may disturb rather than aid recovery of gut microbiota.
Additionally, in children, the use of probiotics to treat diarrhoea and vomiting also appears to be ineffective at reducing clinical symptoms and recovery time.
Probiotic supplements often consist of one strain. This can promote overgrowth of one type of bacteria. In addition, the gut microbiota is made up of thousands of bacterial species, so consumption of one type oversimplifies the complex nature of the microbiota. The reason why there are so many bacteria per capsule is because many do not survive the harsh acid environment in the stomach. Those probiotics that do survive and colonise in the intestine- it is still questionable whether they actually do confer health benefit.
Take-home message
- Probiotics may assist some individuals, not everyone responds the same.
- Care should be taken when consuming probiotics
- Consumption of healthy varied diet is recommended to improve overall health and wellbeing.
- Recommend consuming foods naturally high in probiotics include yoghurt, kefir, sauerkraut, pickles, miso, tempeh, kimchi, sourdough bread and some cheeses.
References
https://www.thelancet.com/pdfs/journals/langas/PIIS2468-1253(18)30415-1.pdf
https://www.nature.com/articles/s41575-019-0173-3
https://www.nature.com/articles/s41577-019-0198-4
https://www.nature.com/articles/nrgastro.2017.75
https://www.bmj.com/content/361/bmj.k2179
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145058/
https://www.cell.com/cell/fulltext/S0092-8674(18)31108-5
https://www.cell.com/cell/fulltext/S0092-8674(18)31102-4
https://www.nejm.org/doi/10.1056/NEJMoa1802597
https://www.nejm.org/doi/10.1056/NEJMoa1802598
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2702973
https://www.nature.com/news/2011/111026/full/news.2011.614.html