The microbiome: How gut bacteria regulate our health

By | September 15, 2020

Our bodies contain almost as many microbial cells as human cells. This community of organisms is called the microbiome, and we are increasingly learning what a huge role they play in all aspects of our health.

In this episode of our video series Science with Sam, find out what your microbiome does for you, and how to nurture a healthy internal ecology.

Research has shown that having a diverse microbiome – particularly your gut bacteria – has benefits not only for your digestive health, but many other organ systems, and even your brain. That has led to the idea that treatments targeting the microbiome may be able to improve our mental health.

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Transcript

Bacteria. Viruses. Fungi. We normally think of these organisms as our enemies.

But they aren’t all bad. Our bodies are full of them and it turns out we can’t live without them. But what exactly are they and what do they do for us?

From the moment we’re born, we acquire, and nurture an internal ecosystem of symbiotic bacteria and other microbes, trillions of them in all. In fact there are roughly as many microbial cells in our bodies as human cells. This thriving microbial world is called our microbiome.

While some microbes can make us ill, we need our microbiome to survive. Combined, they are every bit as essential as our heart, our lungs or our brain.

We have microbes living all over our skin and in every orifice of our bodies. But most of the microbiome is found in our gut. Our gut microbes are essential for digestion. They also help regulate hormones and they can boost our immune system.

Our microbiome contains a wide range of microbes, some of which have beneficial effects on our health and some of which are detrimental. A healthy collection of microbes seems to be vital for our wellbeing, protecting against some of the biggest health threats, like heart disease, obesity, diabetes, arthritis and even depression.

On the other hand, having an unhealthy microbiome may be a contributing factor for many common diseases.

Our modern lifestyles, western diets and overuse of antibiotics might all be having a harmful effect on our internal ecology.

So how do you cultivate a healthy microbiome? Well it seems that the more diverse your microbial population is, the better. And the best way to increase your diversity is to eat a wide range of plant-based foods.

Research shows that people who have at least 30 plant-based elements in their diet every week have a wider range of bacteria in their gut, and that’s linked to better weight management, better heart health and better mental health.

One easy way to boost your numbers is to add a teaspoon of mixed seeds to your breakfast – each type of seed counts as one of the elements. Whole grains, nuts and legumes are all good things to add to your diet as well.

For a few very unlucky people, your microbiome can go badly awry.  For years, a man in the US experienced unexplained mental fogginess, dizziness and memory loss. He was repeatedly pulled over for drink driving, even when he said he hadn’t touched any alcohol.

Finally he was diagnosed with a very rare condition called auto-brewery syndrome, which happens someone’s gut gets colonised by Saccharomyces cerevisiae, also known as brewer’s yeast. These yeasts convert carbohydrates into alcohol, so this man was brewing beer inside his own stomach. That might sound fun, but this guy will tell you it really isn’t.

You can learn more about how your microbiome affects your health by subscribing to New Scientist. We’ve even got a special discount for our wonderful YouTube viewers: click the link in the box below and enter the code SAM20 to get 20 per cent off.

The influence of your gut microbes goes a lot further than you might think. In the last 20 years, we’ve learned that they communicate constantly with the brain, perhaps even exerting control over your mood and emotions.

In fact, microbes can produce every neurotransmitter found in the human brain, including serotonin and dopamine. And there are cells in the gut lining that can detect neurotransmitters and send signals to the brain.

Studies have found that when human volunteers are given probiotic yoghurts containing four different types of bacteria, this affects the activity and connectivity in emotion centres in the brain, producing changes linked to healthier emotion processing.

Another study found that pregnant women who were given certain bacteria had lower scores on depression and anxiety tests compared with a control group. Research like this has led to the idea that mental illness could be treated using treatments that change our gut bacteria, which have been dubbed psychobiotics.

Your microbiome is a big part of who you are. So take care of it, and it will take care of you! If you enjoyed this video don’t forget to like and subscribe for more Science with Sam.

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