by Liberty Stembridge, Health Columnist
Published in Health on 14th November, 2018
You may have been hearing about gut bacteria lately, and how it can affect your health. Many of us automatically associate the word "bacteria" with infection and disease, but this is not always the case with your gut bacteria. In fact, your gut bacteria can actually radically affect your health in both helpful and harmful ways. As more and more research appears supporting the important role that our gut bacteria play in maintaining our health, it's time that we all became a bit more educated on what exactly our gut bacteria is, and how we can improve it.
First of all: what is the gut microbiome? In short, it's the population of microorganisms living inside your intestines. These microorganisms come in their trillions and can weigh up to 2kg in total. About two thirds of your gut bacteria is entirely unique to you, acting as a sort of fingerprint by which you can be recognized. The remaining one third is shared amongst all humans. Many of the bacteria living in your gut are essential to human survival - without them, we'd be dead. Some of them aren't so beneficial, but the vast majority are.
Your gut bacteria is so important because it can affect your health, all over your body. A properly balanced gut microbiome means you have a wide variety of healthy and helpful bacteria in your gut and not too much of the bad bacteria. When the balance of your gut bacteria is upset, the ramifications can be widespread. Not only are you more susceptible to illness, you may also suffer digestive issues, mental health problems, weight changes and much much more. Although for a long time we have viewed the digestive system as a relatively simple set-up without much effect on overall human health, it is becoming increasingly apparent that maintaining good gut health is crucial to living a long and healthy life.
Every day we learn more and more about how gut bacteria affects the human body, from our blood to our brains to our muscles. The list of things we know are affected by gut bacteria is far too long, but here are some of the key areas that affect many people:
Technically your gut bacteria is outside of your body. Or rather, it forms a defense against invaders trying to get into your body, which makes it part of your outer protection. Your gut bacteria are one of the immune systems first lines of defense, where it interacts with whatever you have come into contact with from the outside world. Your gut bacteria essentially communicate with your bodies immune cells to tell them how to respond to this foreign invader. If you haven't got enough properly functioning gut bacteria, your immune system may not be able to respond appropriately to an invading pathogen and you'll end up getting sick.
Even more fascinatingly, there seems to be a link between the genes found in out gut bacteria, and our own DNA. In a 2012 study looking at babies gut health, it was found that there is a link between the genes that were "turned on" in a babies immune system and the genes that were "turned on" in the gut bacteria, suggesting that our gut bacteria could potentially affect our DNA.
Unsurprisingly, your gut bacteria can also affect your gut health and may play a role in contributing to intestinal problems such as leaky gut syndrome, irritable bowel syndrome and inflammatory bowel disease. It's been suggested that the uncomfortable symptoms such as cramping, gas, bloating and more that people suffering from IBS experience could be caused by unhealthy gut bacteria. When we have a build up of certain bacteria within out guts, they can produce a lot of gas and other substances, which then may cause the symptoms of intestinal upset. It's also been found that taking certain probiotics (which contain good gut bacteria) can help to relieve the symptoms of IBS, which further suggests that there is a link between the two.
How can your gut bacteria affect your heart - in a lot of ways, apparently. The most significant is the production of a compound called TMAO that is produced by gut bacteria when they feed on certain foods such as meat and eggs. It's been found that people who have this compound in their blood are 2.5 times more likely to have a heart attack or stroke than people who have very low levels of the compound. Studies like these are showing an increasing link between your diet and gut health, and how it can actually prevent or treat major illnesses such as heart disease.
A link between the gut and the brain (often called the gut-brain axis) has been suggested for quite some time, but it hasn't been until recently that researchers have taken it seriously. The gut-brain axis is essentially like a communication line between the brain and the gut, by which they signal to each other and can affect the functioning of each other. The brain can affect how our digestive system absorbs and secretes food, thereby controlling things like weight gain and vitamin absorption, while the gut can affect how our mood by altering levels of neurotransmitters within the brain (among other things). As our gut bacteria affects our overall gut health, there is now an increasingly clear link between our gut bacteria and our mood. Of course, there are many other factors that contribute to how we feel and think, but this gut brain-connection and how it is affected by our gut bacteria may explain certain phenomena such as mood disorders appearing in people who suffer with intestinal problems.
The tiny invisible-to-the-naked-eye bacteria that live in your gut can actually affect weight loss and how quickly you can lose or gain weight. Studies have shown that an imbalance of healthy gut bacteria (dysbiosis) can actually contribute to weight gain and obesity, while a healthy balance of gut bacteria can help regulate your weight, or help you to lose weight. In studies looking at identical twins, one being healthy and the other being obese, it was found that the gut microbiome was very different between the two, and that when the gut flora of the obese twin was transferred to a mouse, the mouse gained weight. It might be that taking probiotics and improving your gut health could be an important factor in losing weight.
How do you know if you've got good gut bacteria or if you're suffering from an imbalance? Well, one method is to get your gut bacteria tested in a lab to show you your unique gut microbiome and how you could improve it. However, this can be costly but there are still signs that suggest you may not have a healthy gut microbiome. If you frequently find yourself with an upset stomach, skin irritation, becoming intolerant to certain foods, losing or gaining weight for no apparent reason or if you eat a high sugar diet, you may well be suffering from an imbalance in your gut bacteria.
Luckily, there are lots of ways you can improve your gut health. Your gut bacteria is very sensitive to environmental changes (with that mostly being what you eat) so if it is unbalanced because of your diet and lifestyle, it can be rebalanced with some simple changes.
Your diet is key to maintaining a good gut microbiome - eating a range of diverse plant foods with fermented foods means that you get a diverse array of healthy bacteria. Fermented foods in particular contain a lot of healthy bacteria, mostly a special type called Lactobacilli, and this can help to stabilize your gut health and get rid of harmful gut bacteria, so stock up on sauerkraut. Cutting out or cutting down on certain foods is also important. Meat, dairy, sugar and artificial sweeteners such as aspartame have all been linked to dysbiosis and can go on to cause disease if the gut bacteria imbalance goes on for extended periods of time. Lastly, you can also take probiotics, most commonly in pill form, to help balance your gut microbiome by introducing healthy bacteria back into your body. These can be especially helpful if you have had to take a course of antibiotics for any reason, as the antibiotics can kill of the good bacteria, so introducing it back into the body is very important.