Blog > Bacteria in the gut - tiny microbes that can have a huge impact

23 February 2018

There are as many as 100 trillion bacteria that live inside and on our bodies. Some exist on the surface of our skin, others are inside our nose, mouth and even our urogenital tract. However, many bacteria are active inside our gut. The good bacteria inside our gut can counteract potentially harmful toxins and bad bacteria, helping to keep our digestive system fully functioning and healthy.

The gut microbiota, also known as gut flora, is helpful right from the moment we’re born, when intestine colonisation begins. It teaches our immune system to acknowledge and neutralise the harmful bacteria that can cause disease.

What are gut flora?

Gut flora contains trillions of different microorganisms, with as many as 1,000 different species of bacteria active inside the gut at any one time. Around a third of our gut flora is common in all human beings. The other two-thirds is entirely unique to our personal make-up. In short, much of the gut flora inside your gut and intestines is like your very own personal ID card.

There are many uses for our unique gut flora which have direct implications on our health and wellbeing:

  • Gut flora improves the digestion of food and drink that the stomach and small intestine are unable to digest.
  • It creates a unique barrier to infection and disease, educating the immune system about potentially harmful bacteria.
  • It aids the production of important vitamins in our system, notably vitamin B and vitamin K.
  • It seeks to counterbalance aggressions from other microorganisms.

Bacteria-influenced allergies and disorders

Autoimmune allergies and disorders are very much on the rise. In fact, in some quarters, medical experts believe they have reached pandemic levels. Asthma now affects more than a third (37%) of children in the UK, while type 1 diabetes cases have soared by almost a quarter (23%).

Medical experts believe that the reason allergies are becoming more prevalent is that young people are not being exposed to enough bacteria. Medical scientists and researchers have labelled this the ‘hygiene hypothesis’. They believe that our living environments are now too clean, promoting the growth of allergies as youngsters are not exposed to enough bacteria and allergens to develop an immunity to them as they grow older.

In order to train our children’s microbiota to recognise harmful bacteria and develop immunities against them, it’s important to take on board the following advice:

  • Don’t be afraid of your children getting dirty. Let them play around in the mud and dirt that is free from pesticides and fertilizers that kill off all harmful bacteria.
  • Practise keeping clean with your children, such as washing hands after using the toilet, but don’t overuse antibacterial wipes, creating sterile, bacteria-free living environments.
  • Only use antibiotics when they are absolutely necessary. Most colds, sore throats and ear infections don’t need antibiotics to speed up the recovery process. Overuse of antibiotics will result in bacteria becoming resistant to them. They will then be unable to treat more serious infections.
  • It is recommended to increase the intake of probiotic foods which are far superior to consuming probiotic supplements. We’ll go into greater detail on probiotics later in this article.

How to promote growth of good digestive flora

If you’re keen to cultivate good digestive flora in your gut, resulting in a more resilient digestive system and stable wellbeing, consider the following tips:

  • Limit your intake of sugar and processed foods – a scientific investigation of high-sugar diets in the gut bacteria of mice found that it impacted on their short and long-term memory as well as their health. Foods containing glucose and fructose disrupt a healthy microbial balance as they are digested too easily, absorbed into our small intestine without any assistance from our microbes, leaving us flora to eat away on the lining of our intestines, which is the barrier between our gut and the rest of our system.
  • Consume more plants and fibrous foods – eat more green, leafy vegetables to maintain a richer, more diverse microbiota. Fibrous foods are good for our flora to feast on, maintaining our intestinal lining and sustaining a variety of bacteria in our system, which is paramount to our long-term health.
  • Consume less red meat and animal produce – a 2013 study by Harvard University scientists found that individuals on a more omnivorous diet produced more of the bilophila microbe, which has been found to cause inflammation and intestinal disease in mice. The study also claims omnivorous diets produce more of the chemicals directly linked to heart disease than those of vegetarian and vegan diets.

Probiotic foods

Probiotics are live microorganisms that can improve digestive health, reduce depression and promote a healthy heart and mind. While probiotic supplements are increasingly popular in the supermarkets, it’s best to consume genuine probiotic foods that are created using bacterial fermentation. Here are the most effective probiotic foods that you should look to integrate into your diet to promote the growth of good flora in your gut:

  • Yoghurt – this is made from fermented milk including good bacteria such as lactic acid bacteria and bifidobacterial. Not only is it good for your gut, it also promotes stronger bones and aids those with high blood pressure.
  • Dark chocolate – featuring both prebiotics and probiotics, you’ll be pleasantly surprised to hear that dark chocolate is a good source of microbes for your gut. Dark chocolate that has at least 70% cacao content is recommended.
  • Sauerkraut – extremely popular in central Europe, sauerkraut is rich in vitamins, minerals and antioxidants. This finely-cut cabbage is fermented by lactic acid bacteria and can be stored for months in airtight containers.
  • Kimchi – it’s no surprise that the Koreans live longer than most people on this planet. This fermented spicy cabbage features chilli, garlic, ginger and onions to create a delicious Asian-style slaw that is rich in lactic acid bacteria that benefits digestive health.
  • Miso – this Japanese seasoning is made from fermented soybeans, salt and a fungus called koji. It creates a paste which is regularly used to create a soup or broth that Japanese locals consume regularly at breakfast. It’s rich in protein and fibre and various vitamins and minerals such as manganese, copper and vitamin K.
  • Sourdough bread – this bread is created by wild yeast and friendly bacteria breaking down the sugars and gluten in the wheat flour to create proteins, vitamins and minerals that are good for you.
  • Cottage cheese – not all cheeses will feature live and active cultures. However, most cottage cheese is crammed with protein that is slow-digesting and proven to enhance probiotic absorption in the gut.

What else can bacteria in the gut affect?

There are many ways the bacteria in your gut can affect the rest of your body, aside from digestion:

  • Immunity – around 80% of your body’s immune system is situated in the gut. Consequently, if your gut flora is well-balanced, your immune system is more likely to function as it should and help to fight off unwanted illnesses.
  • Mental health – the gut is often medically referred to as our body’s second brain. That’s because our intestinal wall features hundreds of millions of neurons which operate your enteric nervous system. This produces neurotransmitters that are responsible for regulating your mood.
  • Weight – even if you eat healthily and work-out often, it can still be difficult for you to lose weight – the reason may be found in your gut flora. Slimmer people tend to have a very different set of bacteria in their gut than larger people. Sometimes antibiotic overuse can influence a change in characteristics. Meanwhile poor dietary choices can also be linked to the changing characteristics, slowing down metabolic rates.


1. Yakult 
2. Gut Microbiota for Health 
3. Wired 
4. Mind Body Green 
5. Everyday Health 
6. Nature

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