More than a gut feeling: a look at the battle between good and bad bacteria inside our bodies

The battle inside you between good and bad bacteria goes beyond mere digestive comfort. We take a closer look at the research linking microbial health with your immune system, moods and weight.

Probiotics are being proposed as the solution to a broader, more complex range of medical conditions.

Here’s something to think about: as you sit there reading this, a battle is raging inside you. It’s outright war between a community of trillions of bacteria – at least 1,000 different species of them that together weigh up to 2 kilograms – and they are all trying to establish dominance in your gut. You think it’s just another mystery of the body that you can’t even feel, but unbeknownst to you, it’s affecting every bit of your anatomy, from the way your brain functions, to whether there’s a healthy glow to your skin. And it all comes down to the type of bacteria that wins, depending on what kind of environment you’ve set up for it.

There’s good bacteria, and there’s bad bacteria, and the type that is more firmly entrenched in your intestine doesn’t just decide how well you digest your meals, respond to allergens and fend off illness, it also helps determine how much weight you’re likely to gain. Or lose.

"Simply put, if you get the microbiome – that collection of bacteria inside you – healthy, you will lose weight," says Raphael Kellman in his book, The Microbiome Diet: The Scientifically Proven Way to Restore Your Gut Health and Achieve Permanent Weight Loss. "It's less about eating a certain percentage of carbohydrates, protein and fat than about correcting the overgrowth of unhealthy bacteria, which is making you crave the wrong foods, triggering inflammation."

Like fingerprints, the composition of gut flora – or microbiota – in our guts is unique to each one of us. In fact, the gastrointestinal tract is one of the most complex microbial ecosystems on Earth. Our gut flora are part of our immune system, and 80 per cent of these organisms originate in the gut and are a direct result of what you choose to put in your body.

Recent research has found that gut flora plays an instrumental role in how the body functions.

Gut flora promote “normal gastrointestinal function, provides protection from infection, regulates metabolism and comprises more than 75 per cent of our immune system,” says Danesh Goplan, a gastroenterologist in Dubai. Poorly regulated gut flora – dominated by bad bacteria – has been linked to “diseases ranging from autism and depression to autoimmune conditions like Hashimoto’s, inflammatory bowel disease and type 1 diabetes, not to mention both obesity and diabetes”, says Dr Goplan.

Causes of unhealthy gut flora

Several features of the modern lifestyle, says Agkop Avakian, specialist gastroenterologist at the Saudi German Hospital in Dubai, contribute to unhealthy gut flora. The overuse of antibiotics and medications such as non-steroidal anti-inflammatory drugs promotes the growth of bad bacteria. A diet that is high in processed food, refined carbohydrates and sugar, and low in fermentable fibres, also leads to an unhealthy gut environment, which can make it difficult to lose weight and ward off obesity. Chronic stress and chronic infections are also problematic; one day of stress has been proven to throw an entire microbiota out of sync.

Recent research has also shown that babies who are not breastfed and are born to mothers with bad gut flora can later develop unhealthy gut bacteria, which can cause obesity later in life.

Why the good bacteria is good

There’s a reason doctors advise you to eat plenty of yogurt when you’re taking antibiotics for an illness. Antibiotics decimate the colonies of good bacteria in your gut, and the probiotic bacteria found in fermented foods like yogurt can restore the healthy balance of your gut’s microbiota. “I tell all my patients to eat plenty of plain, unprocessed yogurt when I prescribe them any antibiotic,” says Dr Avakian.

Probiotics – the good bacteria – help to counteract inflammation and control the growth of the bad bacteria that causes diseases. Probiotics also help in producing vitamins, absorbing minerals and eliminating toxins. Research also shows that probiotics can control asthma, reduce the risk of allergies and help benefit your mood and mental health. Finally, probiotics can normalise your weight and aid in needed weight loss.