Q) I’ve read that taking a probiotic can help me with stress and depression. Is there any truth to this?
A) Probiotics are supplements (usually in the form of a capsule or pill but they can also be sold in many other dosage forms and are also found in foods such as live cultured yogurt, kefir…) that contain millions to billions of bacteria of various types that are generally classified as “good” as opposed to the bad types that make our throat sore or ears ache.
Our body contains 10 times more bacteria cells than human cells and they can be found just about everywhere throughout it. Given the sheer number of bacteria we harbour, there has been a ton of attention paid to our microbiome (the fancy term we use for all of the bacteria that lives naturally within us) by scientists (and vitamin companies!!) based on the logic that they must be there for a reason (which of course did not stop us from randomly removing tonsils for a few decades, but perhaps we are learning..).
They have been aggressively marketed for various ailments and it is now estimated that over 35.9 billion dollars (US) worth of these supplements were sold globally in 2016 with sales expected to continue to climb as more and more people hop on the bandwagon.
Overall, there is a lot to like about probiotics. Even the most ardent of skeptics feel that they are, if nothing else, relatively harmless and there is decent evidence that they can be beneficial in preventing such things as diarrhea caused by antibiotics or infections, easing the symptoms of irritable bowel syndrome and inflammatory bowel diseases (Crohn’s and colitis) and there is some degree (the key word here being “some”) of evidence that they may help you lose weight, lower your cholesterol, boost your immune system and lessen your allergy symptoms.
Now the various health blogs and websites are promoting probiotics as being effective for the treatment of mental health issues. The fundamental question that needs to be asked of course is whether there is any truth to this or is all just hype.
Let’s examine the evidence piece by piece.
First, there is definitely a connection between your intestine and brain, which scientist refer to as the gut-brain axis.
We know that the intestine has its own separate nervous system and that it produces many of the same neurotransmitters (such as acetylcholine and serotonin) that the brain does. We also have pretty decent poof that the brain and gut can communicate with each other by using the hormone cortisol (our major stress hormone) to send messages back and forth.
We also know that certain psychological conditions such as anxiety and depression can cause gastrointestinal issues such as abdominal pain, diarrhea and constipation. There is also evidence that chronic abdominal pain or constipation may result in anxiety and depression.
Most of us already know this intrinsically. When we are stressed, we frequently feel sick, and when our gut isn’t healthy, far too often your brain’s in a cloud as well.
However, before you drop a $100 a month on the most expensive probiotic available (which incidentally may not be the best one or even a good one, remember this is a billion dollar category and where there is money to be made, dishonesty is always nearby) so let’s examine what we don’t know just yet.
Let’s start with the basic probiotic tenant which is to pound the gut with billions of allegedly good bacteria in order to suppress the bad ones. The problem here is twofold: we don’t really know for certain exactly what the good types of bacteria are (what is good in one part of the body can be toxic elsewhere), and, even if we identify the “beneficial” strains, we have no clue as of yet which ones “talk” to the brain.
An additional problem is the acid within our stomachs. The vast majority of bacteria types cannot survive (lactobacillus and bifidobacteria can) the passage through our stomachs so we have to hope that the ones that do are the same species (which, remember, are still unknown, refer to point one) that will just happen to affect our brains. Not impossible, but perhaps unlikely.
Lastly, the answers as to which bacteria is best may well differ amongst individuals. Just as there is no single antidepressant that is the best solution for all of us, it is quite possible that the best species of bacteria will not be the same for all of us.
As of now, the scientific data to support the hypothesis of probiotics as being good for our mental health is sorely lacking. That is not to say they don’t help, we just don’t have proof of it yet.
For me, despite all that I have said in the second half of this article, I would have no problem trying them given their demonstrated lack of side effects and their relatively low price point for any of the mental health disorders. I just wouldn’t pin all of my hopes on them or break my bank account to do it .