When we think of bacteria, we think of our biological selves. It is not usually the case that we attribute mood changes and mental states to proliferation of bacteria. More evidence is amounting that this is a mistake, however. Gut bacteria can communicate with the brain in various ways. The good news is that there are types of bacteria available to you that can work in beneficial ways with your brain, thus enhancing your moods and cognitive functions.
There is a lot of hype around ‘friendly’ bacteria, but how much of it can we be sure is true? Marketing of such bacteria as health promoters in the form of probiotic yoghurts and other supermarket items is perhaps a clever PR stunt. The efficacy of these products is not really in question, but at least the upshot is that people are (to varying degrees) concerned with what is going on in their gut. The popularity of such yoghurts and high-street probiotic products indicates as much. Maintaining balance in our microbial environments is becoming increasingly important to people, and rightly so.
Your gut bacteria could literally be ‘changing your mind’, according to some studies done on the subject. So the question is not essentially a new one; what are you eating – and what can you eat – that will positively influence the way you think?
Bacteria communicate with the brain
It’s a question of brain chemicals. Different types of bacteria create ‘neural messengers’ which influence your cognitive function. For example, Bacillus makes Dopamine and norepinephrine, Bifido-bacterium makes Gamma-aminobutyric acid (GABA), Enterococcus makes Serotonin, Escherichia makes Norepinephrine and serotonin, Lactobacillus (this is one you’ll have seen on yoghurt cartons) produces Acetylcholine and GABA, and Streptococcus also produces Serotonin.
As you can see by the number of types of bacteria that produce serotonin, it makes sense that mood can be enhanced through the consumption of certain bacteria. It is important to be aware of which types of bacteria produce beneficial results because there are many more that are detrimental to the body. Microbes are nothing new to human beings, whether we give them much thought or not. Our resilient bodies are able to handle many kinds, even the unsavoury ones, so it’s only when they proliferate and overwhelm our systems that we notice their presence.
There are many kinds of microbes, and in many cases, we need them just as much as they need us. Striking the balance between those that we should welcome and those that we must eliminate is the trickier part. This is because there is not yet a definite recipe for a healthy microbial presence, and it is different for each person. On top of this, we can put them in consciously, but they do not always survive inside us.
Scientists have not yet discovered exactly how the communication happens between the microbes and the brain, but the results are still clear. What they do know is that the gut bacteria and the brain have something in common, in that they ‘speak the same language. The gut bacteria can influence the way that the central nervous system utilizes the neurotransmitters serotonin, norepinephrine and dopamine. The gut sends signals via the vagus nerve, although it is not clear exactly how this works.
Some are friendly, and some are most definitely not
Two bacteria that you’ll want to steer well clear of are Escherichia coli and Campylobacter. These can at worst be deadly, and at best can alter the brain chemistry to cause depression and dark moods. They’re unfortunately not alone in this either; there are other types of bacteria linked to depressive states.
Although we don’t approve of this kind of testing, there have been tests done on lab mice that show that when they were born with no bacteria introduced into their systems, they exhibited all manner of strange and antisocial behaviours. Fruit flies have been influenced in similar ways, with microbes causing changes in their mating selections. Our human bodies are full of different types of bacteria; it is thought that there are as many bacterial cells as there are human cells within us.
After taking probiotics, people have shown improvements in visual memory. Even this kind of bacteria found in yoghurt has been shown to positively affect brain activity during stressful situations, with people reacting less intensely to negativity. This is because the processing of emotions and pain sensations is improved by gut bacteria.
The studies done on the subject have highlighted the complexity of it, and the results could of course be attributed to other behaviours and habits, so it may not be entirely obvious to anyone that this is happening within them. When a person experiences changes in bacterial input (e.g. antibiotics, or probiotics, or an infection) coinciding with mood changes, this is an indication that you should look into it.
It works both ways
An interesting aspect of this is that our behaviour, in turn, can have an effect on the microbes residing within us. Taking probiotics (natural or supplemented) like natural yoghurt or kefir can really help. If your diet contains plenty of ‘prebiotics’ (nourishment for your ‘good’ microbes) like onions and garlic, this can also help.
When you have stress in your life, caused by bacteria or otherwise, you can take steps to diminish it and this will in turn positively influence the microbes in your system. This indicates that we have a relationship with our microbes in which neither is really ‘in the driving seat, so to speak. What we do know is that we can encourage balance through introduction of the more positive microbes and limiting anything that will upset the balance or introduce unwanted bacteria, such as antibiotics and those microbes residing in undercooked or rotten foods, and those in unhygienic places, such as toilet door handles.
Choosing a good probiotic is essential for healthy gut bacteria, and it is sometimes necessary to question the quality and quantity of the bacteria you are told is ‘good’ within common marketing. You would need to consume a great deal of supermarket yoghurt to gain any benefits from the bacteria, if it is even still alive at all, and there are often other unwanted additives in such products. A safer bet is a strong, shelf-stable probiotic designed especially to safely and effectively proliferate your ‘friendly’ bacteria in the gut.