Does gut bacteria affect your happiness?

The gut microbiome (i.e. the bacteria in our gut) has been getting lots of attention recently. Scientists are becoming increasingly aware of the key role these trillions of microbes play in health and disease. Not only do these gut microbes within us help us digest food and metabolize drugs but over the past decade, research has shown that they also influence our immune system, inflammation, allergies, metabolism, appetite/ weight and athleticism as well as our behaviour, brain function and mental wellbeing.

Is your gut health responsible for your happiness? Although many factors may influence how happy you feel, there is a definite link between your gut health and mental health. Consider the following:

  1. A study of two large groups of Europeans found that several species of gut bacteria are missing in people with depression. Jeroen Raes, a microbiologist at the Catholic University of Leuven in Belgium, and his colleagues took a closer look the gut microbiome of 1054 Belgians. 173 out of the 1054 Belgians had been diagnosed with depression or had done poorly on a quality of life survey. Upon comparing their microbiomes with other participants, the team found that two kinds of microbes, Coprococcus and Dialister, were missing from the microbiomes of the depressed subjects, but not from those with a high quality of life. The finding held up when the researchers allowed for factors such as age, sex or antidepressant use, all of which influence the microbiome. They also found the depressed people had an increase in bacteria implicated in Crohn disease, suggesting inflammation may be at fault. 
  2. From the same study, Raes and his colleagues began looking for something that could link microbes to mood. They compiled a list of 50+ substances important for proper nervous system function that gut microbes either produce or break down. They found, for example, that Coprococcus seems to have a pathway related to dopamine, a key brain signal involved in depression, although they have no evidence how this might protect against depression. The same microbe also makes an anti-inflammatory substance called butyrate; we know that increased inflammation is implicated in depression.
  3. Serotonin is a major chemical involved in the regulation of mood and emotion.  Although this “happy hormone” is well known as a brain neurotransmitter, it is estimated that 90% of the body’s serotonin is made in the digestive tract. And it turns out that certain bacteria in the gut are important for the production of peripheral serotonin. In one Caltech study, researchers found that germ-free mice produced approximately 60% less serotonin than their peers with conventional bacterial colonies. When these germ-free mice were recolonized with normal gut microbes, the serotonin levels went back up, showing that the deficit in serotonin can be reversed using proper bacterial colonies.
  4. Professor of Genetic Epidemiology at King’s College London Tim Spector remembers the moment when he realised the centrality of the gut. As director of the country’s biggest twin registry, he had always wondered how identical twins can be so different, even with exactly the same genes. How can one be fat while the other, thin? One happy, the other sad? He came to the answer when he compared the gut microbiota of different sets of twins: “One of the biggest factors was that their microbes were different,” he recalls. It turns out that genes are not the only factor dictating one’s health.

What does that mean for us? What can we do to ensure a healthy gut microbiome?

  1. Eat a variety of different healthful foods. Focus on consuming as many different plants, and parts of plants, as possible. Vegetables, nuts, seeds, fruits, fermented foods like kefir, kombucha, kimchi, sauerkraut and yogurt promote good gut health.
  2. Increase your fibre. Prebiotics are types of dietary fiber that feed the good, friendly bacteria in your gut. This helps the gut bacteria produce nutrients for your colon cells and leads to a healthier digestive system. Avoid processed foods, artificial sweeteners and meat reared using antibiotics.
  3. Avoid the use of antibiotics in infants and children unless it’s absolutely necessary. Dr. Ardyce Yik ND treats many infections in children naturally using antimicrobial medicinal herbs and nutraceuticals. She is also trained to know when to refer to a medical doctor if pharmaceutical antibiotics or drugs are needed. Click here to read more about how antibiotic use in infants is linked to disease later in life.
  4.  Contact with a variety of bacteria is recommended, too. Perhaps there’s more than one reason why children with pets are happy and healthy (Pets can boost your child’s immunity!).
  5. Find a licensed naturopathic doctor or functional medicine practitioner who can help you find out more about your gut health. Gut health tests such as the GI-MAP can detect and identify microbes in your gut which may be contributing not only to your mental health concerns but also to your GI symptoms, chronic health issues or weight loss challenges.



Bacteria may live naturally inside the human brain


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