How Your Gut Bacteria Is Affecting Your Weight, Mental Health And Immunity

They call it a ‘gut feeling’ for a reason… 

Everyone knows ‘you are what you eat’, but, as it turns out, the secret to good health could be less about what we’re eating and more about the bacteria in our stomachs.

Our gut contains over 100 trillion bacteria, and this bacteria helps us to break down food and absorb nutrients – and a whole lot more. New research is starting to uncover powerful links between our health and what’s going on inside our guts.

Whether your issue is always calling in to work sick, shifting a dress size, experiencing bouts of depression or suffering from anxiety, the microscopic creatures living in your stomach may have more to do with it than you think…

Your gut health and your weight

If you’ve ever struggled to shed stubborn weight, even when eating well and exercising, it could be because of a gut bacteria imbalance. Gut bacteria affects a lot of what goes on with our stomachs, including controlling our metabolism, cravings, how many calories our bodies absorb from food, the way we store fat, how we balance levels of glucose in the blood, and even how our hormones interpret if we’re hungry or full.

A lack of the right bacteria may even predispose us to obesity and diabetes, according to a 2013 study from Nature, which found that having a more diverse collection of bacteria in your gut could make it significantly easier to stay lean.

“The diversity of microbes in our bodies is 30 per cent lower than it was 50 years ago, which may contribute to the obesity epidemic,” says King’s College London’s genetic epidemiology professor, Tim Spector.

How your gut affects your brain

When people say they have “a gut feeling”, they aren’t just speaking metaphorically. Research shows the make-up of our stomach bacteria can actually have a serious effect on our mental health. We have around 500 million neurons embedded in our intestinal wall, which make up our enteric nervous system (ENS). The ENS helps in the production of neurotransmitters, which are super important for regulating mood.

“We now believe 95 per cent of our serotonin – a neurotransmitter essential to mood stability that antidepressant medication helps regulate – is made in our guts,” explains Spector.

In numerous case studies, including a 2013 study published in Cell journal, researchers found if they changed the gut bacteria in mice, it completely altered how they behaved.  The mice with balanced gut bacteria were more adventurous and appeared calm, while those with unbalanced guts displayed classic signs of anxiety and stress. Another 2013 study by UCLA, tried to replicate this finding in humans, giving some women beverages with probiotics to balance the gut, and some without probiotics, and then examining their brains after a few weeks on the protocol. The study found the women with more balanced gut bacteria as a result of consuming the probiotics were less emotional and generally calmer.

The gut-immunity connection

If you’re one of those people who only has to look at someone sneeze and you’ll be calling up sick the next day, it could be because of an imbalance in your gut bacteria. Up to 80 per cent of our immune system is located in our gut, so if your gut bacteria is balanced, your immune system will function better. Conversely, if it’s unbalanced, you’ll be much more susceptible to picking up viruses and getting run down.

“If we wipe out our gut microbes, then our immune system goes into auto-drive and starts attacking us with autoimmune diseases and allergies,” explains Spector.

“In the past few decades, we’ve been trying to wipe them out [with antibiotics] – without knowing what we are doing – and this is starting to cause us problems.”

Finding the right balance

So, if such a wide range of health problems stem from our guts being out of whack, what can be done to re-balance them? Firstly it’s important to understand we need both kinds of bacteria in our bodies; good and bad bacteria are important for maintaining optimal health, as long as we maintain them in the right ratio to one another. Unfortunately, because good bacteria is so easy to kill (antibiotic use, alcohol and even stress all destroy it), the bad guys can take over, causing a kind of internal bacteria revolt, so it’s critical to understand how our lifestyle choices can influence this for the better, or for worse.

If you have to take antibiotics, when you pick up the script, you should also get some probiotics to help replace any of the good guys you’ve accidentally killed off while fighting your virus or infection. In fact, regularly consuming probiotics, even if you aren’t sick, will help to balance the good and bad bacteria in your gut.

Changing your diet to include more fiber is also an easy way to sort out your stomach, according to Standford University research on gut bacteria. Fiber can help improve the diversity of stomach bacteria, making weight control a decidedly easier affair.

“If everyone doubled their fiber intake, they would see dramatic results,” says Spector.

Reducing stress is another key way to balance your gut bacteria. A 2013 study published in the Brain, Behavior and Immunity journal found a direct relationship between high levels of stress and higher levels of bad bacteria in the gut.

When lifestyle changes aren’t enough

If your gut-related health problems  are really serious, and a lifestyle and diet change don’t fix the issue, there are some medical procedures you might need to have.

C. difficile colitis is a condition affecting the large intestine and is caused by taking too many antibiotics and killing off good bacteria. If taking an opposing antibiotic – which your doctor can prescribe – doesn’t help the problem, you may have to undertake a fecal transplant, a procedure where the faeces of a healthy donor is transplanted into your colon, and the good bacteria in the donor’s stool helps get rid of the bad bacteria (don’t worry, it’s not actually as icky as it sounds; it’s all done by a specialist surgeon in a completely sterile environment).

For sufferers of obesity or diabetes, gastric bypass surgery may be necessary when lifestyle changes aimed at improving your gut health aren’t enough. A 2015 small-scale study from Sweden found that undergoing gastric bypass surgery can actually help to re-balance bacteria in the gut, making it easier to maintain weight in the long-term.

And even if you think your gut bacteria’s fine, it’s worthwhile doing everything you can to maintain a healthy stomach, because researchers are only just starting to scratch the surface of how many different illnesses could actually be completely prevented through better gut health.

This story was originally published in May 2018 and has been republished here due to popularity. Images via tumblr.com and giphy.com.

Comment: Do you suffer from health issues for which probiotic use has helped?