Challenges regarding survival of probiotics in the stomach acid and common solutions.

by Mahfuzul Hasan

We are all familiar with different probiotic containing foods such as yogurt. Probiotic organisms mainly represent the vast number of beneficial bacteria or yeast species that naturally live within our body. In fact, we have nearly trillion microbes on and inside our body ((Probiotics: What is it, Benefits, Side Effects, Food & Types, 2020)).  These beneficial microbes often balance our health by competing with infectious microbes. Currently, food supplements are the most widespread means of adding these beneficial microbes in our body. 

A common concern regarding effectiveness of probiotic food supplements may be due to the highly acidic nature of our gastric juice in stomach. The pH level of human stomach mostly ranges within 1.0 to 2.0 which is necessary for digestion of foods (Holland, 2020). This high pH can affect the survival of the probiotic microbes and this raise questions regarding whether spending money on probiotic food supplements is a waste. Therefore, scientists from University College London (UCL) conducted three experiments on eight probiotic products and found that, only one of the tested probiotics survived the gastric acid and reached the intestines (Scott-Lutyens, 2014). Certain probiotic strains can survive the harsh acidic environment in the stomach and while manufacturing supplements, incorporation of few tests can ensure the effectiveness of the products. 

Firstly, a common approach in ensuring survival of microbes in stomach may include pH testing of the strains used. The microbial strains can be exposed to different levels of acidity in order to determine the percentage of microbes that would survive in various pH ranges. Such tests would provide an overview of which microbes could be useful in food supplements in the developmental stages. 

Secondly, coating technologies can be useful for protecting the microbes within the low pH of the stomach (Wheddon, 2019). The coating of the capsule would remain intact in the stomach an it would be dissolved in the intestines where the organisms would be released to perform their function. 

Thirdly, the final proof of effectiveness can be ensured by clinical trials. Human trials can be conducted on controlled groups for finding out outcomes in different areas of health. Each probiotic product is targeted towards specific aspects of human health such as gut health, asthma in children etc. Outcomes in controlled human trials would be the final determinant in effectiveness of the product. 

Finally, while making decisions of purchase, the consumers should conduct background research regarding these issues. Moreover, it is suggested to consume majority of the probiotic supplements in the morning since the pH of the stomach remains highest during morning (Wheddon, 2019). Finally, we can conduct mini research by trying different products and find out which works best for us.  

Mahfuzul Hasan

Microbiology Program, Department of Mathematics and Natural Sciences,

BRAC University.


  • Cleveland Clinic. 2020. Probiotics: What is it, Benefits, Side Effects, Food & Types. [online] Available at: <https://my.clevelandclinic.org/health/articles/14598-probiotics> [Accessed 2 February 2021].
  • Holland, K., 2020. How Strong Is Stomach Acid? Plus What to Do When Acid Levels Fluctuate. [online] Healthline. Available at: <https://www.healthline.com/health/how-strong-is-stomach-acid> [Accessed 2 February 2021].
  • Scott-Lutyens, J., 2014. Our response to recent study on probiotics | Professionals. [online] Optibacprobiotics.com. Available at: <https://www.optibacprobiotics.com/uk/professionals/latest-research/general-health/our-response-to-recent-study-on-probiotics> [Accessed 2 February 2021].
  • Wheddon, K., 2019. Do probiotics survive stomach acid? | Probiotics Learning Lab. [online] Optibacprobiotics.com. Available at: <https://www.optibacprobiotics.com/uk/learning-lab/about/probiotics/how-probiotics-survive-stomach-acid-digestion> [Accessed 2 February 2021].

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