An interesting conclusion to several studies recently undertaken is that happier people have a healthier gut. The flip side to this is that people who are depressed lack a certain gut bacteria!
Can Poor Gut Health Cause Depression
Is there a link between gut health and depression? Many people think it could be the case.
It’s a theory that’s been bandied around for quite a while but, as far as the science goes, it’s still too early to say.
The results of a European study shows certain species of gut bacteria are missing from the intestines of people who suffer from depression.
That’s interesting and it certainly suggests there could be a connection.
Unfortunately, the nature of the connection remains a mystery. Does depression purge the gut of certain species of bacteria, or is it the other way around?
Is it the foods that we eat that may be bad for gut flora?
Could the lack of bacteria be causing depression? It’s a little like trying to find the answer to that old conundrum, “Which came first, the chicken or the egg?”
However, although they are still pretty much stumbling about in the dark, the researchers have established certain gut bacteria are capable of producing compounds that affect the function of nerve cells.
These compounds may also be capable of affecting the mood but, again, there’s a lot the scientists do not know.
What the Research Reveals…
People Who Have Depression Lack Certain Gut Bacteria
Researchers at KU Leuven-University of Leuven, in Belgium, have discovered people living with depression (who took part in their clinical trial) had consistently low levels of coprococcus and dialister. This was true regardless of if they were taking antidepressants or not.
While the researchers were studying coprococcus and dialister they discovered the presence of genes coding for butyrate. This is a short-chain fatty acid that can help reduce depression.
Again, it’s important to point out that, although there is a link between butyrate and depression, the research does not prove the two gut bacteria are capable of doing so.
The discovery provides a basis for further study, nothing more.
Although coprococcus and dialister have genes coding for butyrate, it does not necessarily mean the genes re being expressed. It’s possible the bacteria may not produce any butyrate at all.
Even if the bacteria successfully product butyrate, other factors would also need to come in to play.
The fatty acid or its metabolites would have to cross the gut barrier. They’d need to make it through the brain barrier as well before they could directly influence brain function.
Nevertheless, future research may expand the preliminary findings and prove these things are possible.
If it does, the day may come when probiotics become an acceptable treatment for depression and other mental health disorders.
Happier Individuals Have More of a Specific Gut Bacteria
The research also reveals another interesting factor that further suggests a link between gut health and depression.
The stool samples taken from people who did not suffer from depression showed higher levels of faecalibacterium than samples from individuals who did.
Again, this is interesting. The discovery also provides further grounding for additional study, but the findings fail to provide proof that poor gut health can lead to depression.
What the Follow-up Investigations Reveal
Moving forward with their investigations, the researchers found evidence that suggests gut microbes are capable of communicating with the human nervous system.
The neurotransmitters the microbes produce are known to be vitally important for supporting good mental health.
Providing a further explanation, Jeroen Raes, who co-authored the study with Sara Vierira-Silva, said “We found that many [bacteria] can produce neurotransmitters or precursors for substances like dopamine and serotonin.”
Dopamine and serotonin play complex roles in the brain. In fact, due to the way it affects the mood, people often call serotonin the “happiness hormone.”
Serotonin is also integral to many other human biological functions. Strangely enough, this includes eating and digestion. (https://www.hormone.org/your-health-and-hormones/glands-and-hormones-a-to-z/hormones/serotonin)
According to Raes, microbes that occur naturally outside the human body, such as those living in soils, lack the capabilities of the microbes living within the human gut. They are not capable of producing the same kinds of neurotransmitters.
Raes speculates this may be because they did not “co-evolve” with humans. Due to this, they never had the opportunity to learn how to tap into the human nervous system.
Gut Health and Depression – Summary
The relationship between gut health and depression is complex. It could be a long time before science can prove exactly how one affects the other.
However, if low levels of certain gut bacteria do turn out to be the root cause for certain forms of depression, it could open the door for many new probiotic treatments.
If such treatments subsequently prove to be effective many may find them better options than some of the present treatments. Treating depression with probiotics instead of drugs is a more natural way to go.
Unfortunately, it’s likely to be a long time before we see any probiotic treatments that are specifically for depression. Proving the connection is going to require a lot of hard work.
Raes says the first step will be to grow the bacteria in the lab and monitor them to see what substances they produce.
These substances will then need to be incorporated into tailored probiotics suitable for tests on animals. Then, all being well, the compounds will need to be the focus of further tests involving humans.
So, although the research to date is interesting, it’s best to see it as the first step on what could be a very long road.
Where will that road ultimately take us? Only time will tell but the day may come when probiotic products are being used to enhance gut health in ways that will help provide relief from depression.