Unhappy? Check your Intestines


Until now we have been under the impression that depression is an issue of psychology alone, and not general health. However, new research proposes that our mental health might have a lot more to do with our digestive system than we thought – perhaps validating the folk saying that the way to human happiness is through the stomach.

Our brains have long been bestowed the status of “king of the organs” both in medical circles and popular culture. However, studies prove that there is serious communications between the brain and the bowels, what has been called the “gut-brain axis.” This deep connectivity has been cited as the reason for the bowel system’s effects on a range of human states, both physical and emotional.

Our intestines are populated with over 100 trillion kinds of organisms.  Known as “gut flora” or microbiota, the bacteria that dwell in our intestines and conduct a range of beneficial processes for the human body now appear to be a significant element in brain chemistry and, therefore, our moods.

The bacterial situation in your gut is determined by your age, diet, geographical location and general health. The food which you eat has a direct effect on the bacteria which lives on the sidelines of your digestive tract.

Through experimentation involving food, antibiotics, and probiotics (substances which promote bacterial growth), researchers have begun to learn how bacteria can affect our mood.


Serotonin is a chemical which regulates the brain. The function of many anti-depressant medicines is to take control of serotonin levels in order to affect mood. However, most of the serotonin to be found in the human body lives in the digestive tract and not the brain. Serotonin is a byproduct of the processing of tryptophan, found in food proteins like turkey meat. Levels of tryptophan – which affect serotonin production (a job done by gut bacteria – therefore have a link to mood.


Diets with high levels of saturated fat and refined carbohydrates have proven to have a negative effect on gut bacteria – prompting them to cause general inflammation in the human body. This inflammatory state has been further linked to depression.


Take a look on any pharmacy supplement shelf and you’ll see probiotics. These dietary supplements promote the growth of “healthy” bacteria in the gut and have been shown to also possess an anti-depressant effect. Recent experiments showed that the probiotic lactobacilli could affect cortisol levels in the human body, and, therefore, inflammation of the organs.

These theories and their supporting studies are still at their early stages. There might not yet be rock-solid scientific links between microbiome health and mental state, but research is revealing new things all the time. Science might, in fact, only be catching up with what common wisdom has known for years – that someone who, for example, “has butterflies in their stomach” is scared not because of a psychological state, but also because of the situation in their gut. We might very well, in the future, talk about “gut health” in the same way that we talk about mental health today.