The problem with probiotics

The problem with probiotics

A 2021 study analysed eleven commercial probiotics and found that most did not deliver the benefits claimed on their labels. Only two samples had the expected concentration of viable cells and all samples experienced a significant reduction in concentration during digestion, with most failing to meet the advertised standards.1

Further studies have shown that of twenty-six commercial probiotics assessed, none fully supported label claims and some of them contained unacceptable microorganisms.2

In another, it was found that only half of the probiotics examined had the specific strain listed on the label.3

A 2003 South African study found that many commercial probiotics did not match their advertised bacterial content, with only three out of nine products containing the stated bacteria and just five having enough for a probiotic effect. Additionally, some products contained potential pathogens, raising concerns about the accuracy of labeling and the effectiveness of these supplements.4

The degrading effect of the stomach

The stomach produces hydrochloric acid with a pH as low as 1.5-3.5, strong enough to dissolve metal. This acid breaks down food and kills harmful bacteria.

As a result, only 1% to 20% of unprotected probiotic bacteria survive to reach the intestine, where they need to colonize to provide health benefits. A good probiotic delivery system must therefore protect these microorganisms during production, storage and digestion to ensure enough reach to the intestines and maximize their effectiveness.5

A 2017 study tested how well sixteen species of probiotics survived in simulated stomach acid, using ten different oral forms, like capsules and tablets. The results showed that all the strains were very sensitive to acidic conditions and likely wouldn't survive in an empty stomach. Most probiotic products didn't protect the bacteria unless they had some form of protection, which raises concerns about the effectiveness of these non-enteric products in providing the expected benefits of probiotics.6

It is therefore difficult for probiotics to successfully exert beneficial activities within the gut microbiome due to their vulnerability to harsh conditions during manufacturing, storage and passage through the gastrointestinal (GI) tract.

The degrading effect of external elements:

Exposure to heat

Probiotics can be harmed by heat during long-term storage and common manufacturing processes like drying and pasteurization. High temperatures can damage the proteins and cells of probiotics, making them inactive.7,8

Exposure to oxygen

Many probiotic strains are anaerobic or microaerophilic, meaning they thrive without oxygen. Exposure to oxygen can harm probiotics by producing reactive oxygen species that damage their proteins, lipids, and nucleic acids.9,10

Undergoing a drying process such as freeze drying

The process of freeze drying creates osmotic shock and reduces the survival of probiotics. When probiotics dehydrate, water leaves the cells, leading to increased concentration inside the cells, which can damage their functions.11,12

The proposed ideal probiotic delivery13

 

References

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8165489/
  2. https://www.tandfonline.com/doi/full/10.1080/13102818.2019.1621208
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6430388/
  4. https://www.researchgate.net/publication/8666560_An_evaluation_of_nine_probiotics_available_in_South_Africa_August_2003
  5. https://www.studysmarter.co.uk/explanations/medicine/anatomy/gastric-acid/#:~:text=Gastric%20acid%2C%20primarily%20composed%20of,the%20absorption%20of%20essential%20nutrients.
  6. https://pubmed.ncbi.nlm.nih.gov/28093323/
  7. https://onlinelibrary.wiley.com/doi/10.1002/ceat.201100040
  8. https://www.sciencedirect.com/science/article/abs/pii/S095869460400192X
  9. https://pubmed.ncbi.nlm.nih.gov/18266696/
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9769877/
  11. https://pure.rug.nl/ws/portalfiles/portal/6901753/2002MolMicrobiolPoolman.pdf
  12. https://www.scopus.com/record/display.uri?eid=2-s2.0-79959745914&origin=inward&txGid=af3ed013ded17711f7fa3791d7d5f4ba
  13. https://www.researchgate.net/figure/Potential-mechanisms-of-action-of-probiotics-1-Probiotics-inhibit-pathogens-by-competing_fig2_303373386

Information supplied by Probitec.

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