Ethos Ho, BSc Pharm Candidate
How Safe are Probiotics Really?
In last week’s article, we discussed that while the use of probiotics is generally safe for most patients, caution is advised in individuals who are immunocompromised or have a severely damaged gastrointestinal tract. Today, we’re going to delve deeper on the safety of probiotics in immunocompromised individuals, particularly those who received transplants.
This article was inspired by a real-life case at work, where a patient in the nephrology clinic inquired about the potential effects of probiotics on her transplanted kidney. Although the pharmacist and I were unsure about the evidence supporting its use, the theory of probiotics potentially “boosting” the immune system to cause transplant failure and the importance of maintaining a state of immunosuppression formed the basis of the recommendation.
Let’s look at the evidence surrounding probiotic use in transplant patients.
What Does the Evidence Say?
A quick look at the available studies did not yield many results on the topic. One article that evaluated the current evidence on the safety of probiotics found that the main side-effects found were sepsis (infection in the blood), fungemia (fungal infection of blood), and GI ischemia. Individuals who were at an increased risk for these complications included:1
- Critically ill in intensive care units
- Critically sick infants
- Postoperative and hospitalized patients
- Patients with immune-compromised complexity
The expert opinion on these findings was that complete consideration of the risks and benefits need to be made before prescribing probiotics.1
A 2002 joint report by the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) of the United Nations stated that probiotics may theoretically contribute to the following side effects:2
- Systemic infections
- Deleterious metabolic activities
- Excessive immune stimulation in susceptible individuals
- Gene transfer
However, the phenomenon of excessive immune stimulation has not been observed in any human subjects so far.2 A study that looked at the probiotic strain Lactobacillus reuteri in HIV adults found that the organism was well tolerated and did not find significant safety problems.3 Another study that reviewed probiotic safety found no available evidence that immunocompromised patients had an increased risk of opportunistic infection from probiotic lactobacilli or bifidobacteria.4
The Bottom Line
Although it makes sense to avoid probiotic use in transplant patients due to the theoretical risks, these risks have yet to be observed in published literature. Current evidence reveals that probiotic use is well tolerated and does not show any safety risk in immunocompromised individuals. However, it’s still recommended to weigh the risks and benefits of its use for each person. Such as in the case of the transplant patient encountered at work, it may have been more appropriate to suggest that she avoid probiotic use since the risk of transplant failure will outweigh potential benefits she may receive from it.
As always, we hope you took away something valuable from this piece. If you have any questions or concerns regarding this article or others, feel free to reach out to us on Instagram, Facebook, or at firstname.lastname@example.org with your feedback. We’d love to hear from you.
- Didari, T., Solki, S., Mozaffari, S., Nikfar, S., & Abdollahi, M. (2014). A systematic review of the safety of probiotics. Expert Opinion On Drug Safety, 13(2), 227-239. doi: 10.1517/14740338.2014.872627
- Doron, S., & Snydman, D. (2015). Risk and Safety of Probiotics. Clinical Infectious Diseases, 60(suppl_2), S129-S134. doi: 10.1093/cid/civ085
- Wolf, B., Wheeler, K., Ataya, D., & Garleb, K. (1998). Safety and tolerance of Lactobacillus reuteri supplementation to a population infected with the human immunodeficiency virus. Food And Chemical Toxicology, 36(12), 1085-1094. doi: 10.1016/s0278-6915(98)00090-8
- Borriello, S., Hammes, W., Holzapfel, W., Marteau, P., Schrezenmeir, J., Vaara, M., & Valtonen, V. (2003). Safety of Probiotics That Contain Lactobacilli or Bifidobacteria. Clinical Infectious Diseases, 36(6), 775-780. doi: 10.1086/368080