Are Probiotics Safe?

In two prior posts, I have offered my steep skepticism that probiotics deliver on the claims their manufacturers make.  By not being classified as actual drugs, these products leapfrog over traditional Food and Drug Administration scrutiny and are marketed directly to the public who seeks relief from various chronic diseases – conditions that conventional medicine doesn’t handle well.

While I have lambasted the lack of medical evidence underlying probiotic treatment claims, in fairness, I will now offer an opinion that also has no supportive medical evidence.  So, probiotic enthusiasts may wish to call me out as well.

I worry about unproven but plausible risks of long term probiotic use to the individual users and to society at large.  These products are tampering with our own bacterial ecosystem that we don’t yet truly understand, always a dicey prospect.  

And keep in mind that if you scan the labels of probiotics that fill several shelves in retail stores, they are all different with respect to the specific bacterial strains and their dosages.  Where is the science to guide a person to choose the right jar?  

The microbiome – the trillions of germs residing in our digestive systems – is the result of millions of years of evolution.  There are millions of communities of microorganisms inside of us that have learned to live together, both for their benefit as well as for their human hosts.  An equilibrium of sorts has been established which tries to remain stable.  It is an elegant and complex example of symbiosis that scientists have only begun to comprehend.  While there are theories that some illnesses may result from an overgrowth of ‘bad bacteria’, I find it rather simplistic that a proposed remedy is simply to swallow a few billion germs daily purchased from a supermarket or a pharmacy.  I suspect that the microbiome and the human body are much more sophisticated than this.  And, is a changed microbiome the cause of a disease or a result of it?

There are a few narrow medical indications that do have some evidence of probiotic efficacy.  But these agents are being marketed far more broadly in order to capture a huge segment of market share.

A Plea to Yield to Better Judgment

We have all seen the health consequences of disrupting the microbiome with excessive antibiotic use in this country.  Unlike antibiotics, probiotics alter the microbiome by design.  Might there be unknown consequences of ingesting billions of bacteria over months and years based on an ad campaign with the thinnest of evidence?  What hubris!  Tens of millions of Americans have decided that a promise of benefit exceeds any unknown risks.  Perhaps, medical professionals will wonder a few decades from now why we thought that disrupting a system that took forever to develop was reasonable and safe. 

For those who claim today that a disturbed microbiome is the cause of illness, are they not concerned that an altered microbiome might cause new medical conditions?

If promotional material states clearly that the product is not intended to diagnose, treat, cure or prevent any disease, then why would you take it?