The Gut-Mood Connection


We have so many sayings that show on some level we understand that the mind/emotions and body are deeply connected.

    “I feel it in my gut.”

            “I have butterflies in my stomach.”

            “It was gut wrenching.”

            “I’m so nervous I feel like I’m going to be sick to my stomach.”

By now most people acknowledge that their emotions can cause sensations in their body. Who hasn’t experienced having to run to the bathroom if they feel anxious enough? But not many realize that the physical state of the body, specifically gut health, affects mood and anxiety.

The gut is called the enteric nervous system or the second brain for a reason. It is connected to the brain, and is actually in control of many more processes in our body than we realize. For instance, it is where the majority of the immune system is and it has 100 million nerve cells, and 90% of the body’s serotonin is actually produced in the gut. It is also able to act independently of the brain! There is a lot of research out there that explains and proves the connection between the gut and mental health but since I am not a medical doctor and only have a layman person’s knowledge of medical information, I am going to leave it to them to explain.

Here is one article by Dr. Kelly Brogan that discusses how the brain and gut communicate through the vagus nerve and how our diet is a big offender of inflammation (which was mentioned in the previous blog article as a contributor to mental health issues). She also gives some suggestions on how to help treat the gut for your mood.

anatomy-160524_1280Research with Rats

Of course researchers typically start their research with rats and here we can go to some rat studies for more information as well. As discussed in this article from Science Daily, Researchers at the Universtity of Virginia School of Medicine looked at the composition of rats’ gut microbiome before and after stressing them out and found that the major difference was a decrease in lactobacillus (a probiotic) after they were stressed. They also noted that with this decrease came the onset of depressive symptoms in the rats. They then gave them lactobacillus with their food and the rats’ behavior returned to that of a normal, not-depressed, rat. They then found that when the amount of lactobacillus in the gut decreased, the amount of kynurenine in the blood increased. Researchers have already connected high levels of kynurenine to depression as well as inflammation.

In a study at California Institute of Technology (Caltech), researchers looked at the gut microbiome of mice and the amount of peripheral serotonin was created by the cells in their guts. They looked at mice that they deemed “germ-free” and compared them to mice that had a normal gut microbiome. They found that the germ-free mice had 60% less serotonin in their guts.

If that isn’t enough to get you thinking, researhers at the University of Cork in Ireland actually took it another step farther. They took healthy mice who showed no signs of depressive behavior seen in rats and transplanted some fecal matter of depressed people into the rats (this is a way of transferring the microbiome from one being to another). They found that once the rats had the fecal transplant, they also showed signs of becoming depressed, including no longer being interested in the sugar water they had been so fond of drinking previously. This is just like when depressed people lose interest in things that interested them previously (anhedonia).

Antibiotics and Suicidal Thoughts

There have been multiple reports that people with no history of mental health disorders have become depressed and even suicidal after a round of antibiotics. The reason for this is that the antibiotics not only kill the bad bacteria but they also kill the good bacteria in our bodies. I have seen this in my office with people seeking treatment after antibiotics as well as current clients that report suicidal thoughts after being on antibiotics. Although this isn’t a large study, here is one that I found on the National Institute of Health’s website that discusses three cases that occurred after the patients took doxycycline.

I have  seen reports years ago that discussed researchers are being able to link certain probiotics as being helpful for specific conditions. However, most researchers state that we need a large variety of probiotics in order to be healthy both physically and mentally.

Probiotic Treatment

In trying to uncover some information to give you on how to tell if your depression may be caused by poor gut health I found that the list is quite extensive. Remember that the immune system starts in the gut. Therefore, if your gut is lacking in some way, there could be a multitude of signs and symptoms. Personally I think that people who have had frequent rounds of antibiotics or can tell a difference in their mood when taking antibiotics as well as those who also have digestive issues should consider gut health as a possble cause.

Some researchers are looking at treating people with probiotic supplementation but it seems to be questionable still which probiotics are the most helpful and how much is needed to really see a difference. As I mentioned before, a wide variety is normally recommended, however. I think it is pretty safe to say, though, that just eating some store bought yogurt likely won’t provide you with the boost you need, especially since the majority have way too much sugar which can cause additional problems. If you choose to use a probiotic, do your research. There are many out there that boast all sorts of claims and information continues to change on recommendations such as whether it needs to be refrigerated or not.

Many people believe in the power of eating probiotic rich foods over taking a supplement. If you are interested in trying a diet rich in probiotic foods you can research kefir, water kefir, kombucha, sauerkraut, kimchi and other fermented foods and drinks.

In addition to adding probiotics you should do your best to make sure that you eat a diverse diet rich in fiber which acts as food for the probiotics. Other possible things that can help is to reduce stress and exercise more.

Not sure if gut health is your issue but still want to give it a try? You can do so without worry of having to get a prescription or experiencing negative side effects! And if all the diet and supplements don’t seem to help, you could always try a fecal transplant!

In the next blog article, I am going to discuss even more possible causes and how you can work to manage them!