This is how your gut bacteria affects your immune system

Your gut is home to trillions of bacteria that are essential to your health.

This complex system of bacteria benefits your health in positive ways, for example by producing serotonin, a neurotransmitter essential to a happy, calm mood.

But this colony of intestinal flora - sometimes called gut microbiota - is also closely linked to another key function essential to your health, your immunity.

Your immune system is a bit like your body’s boundary system, if it senses something isn’t right, it will respond in a way that promotes healing.

So, making sure your immune system is in top shape is a great measure to keep yourself healthy.

How your immune system is connected to your gut

Your gut contains a thin wall of cells that work as a barrier between what stays in your intestine and what passes into your bloodstream.

Behind that barrier are cells linked to your immune system that are constantly sensing what is in your gut.

These cells are a vital part of the body’s immune response when you’re sick.

Eat for your gut bacteria, support your immunity

Every time we eat, our gut bacteria break down our food and use it to grow.

As this process occurs, healthy gut bacteria produce beneficial compounds that help you function optimally and are beneficial for the way your immune system functions.

It is also possible that if you have an imbalance of bacteria in your gut they can produce compounds that lead to an inflammatory response that isn’t supportive for your overall health and immunity. This can be caused by stress, a highly processed diet or repeated bouts of antibiotics, amongst other things.

That’s why eating a diet that encourages a healthy balance of bacteria is so important – to ensure your gut bacteria (gut flora) aren’t wasting their precious immune response resources fighting inflammation.

Having a gut containing plenty of healthy bacteria leaves the immune system with plenty of time to handle its many complex everyday functions.

Why you need healthy, balanced gut flora

Everyone’s gut flora is individual to them, almost like our own personal bacterial blueprint. So, what’s good for one person, might not work for the next.

But what we do know, is that eating a diet rich in vegetables and fruit and healthy fibres (see below), as well as low in sugar and processed foods, can help the balance of bacteria in our gut.

Try also, to ensure you eat mindfully and slowly, sitting down at the table and taking the time to be present with your food. This helps the digestive process; essential to gut health.

The trick then, is to optimise your lifestyle for a healthy balance of bacteria in your gut, thus maximising your immune system’s ability to do its job and rise to challenges.

5 ways to keep your gut bacteria happy and support your immunity

1. Eat fermented foods such as kimchi, sauerkraut, kombucha, yoghurt and kefir. These are important as they are sources of healthy bacteria.
2. Get enough prebiotic fibre. Prebiotic fibre foods are essential because they feed those healthy bacteria and encourage them to grow. Gut-friendly prebiotic fibres include fruit and vegetables, especially Jerusalem artichokes, asparagus, onions and garlic, tomatoes (see below), whole grains and legumes.
3. Choose vegetables in a range of different colours. These contain essential antioxidants called polyphenols that activate pathways to help reduce your body’s inflammatory response. They are also rich in insoluble fibre that your body can’t ordinarily break down. This is not only good for feeding gut bacteria, it helps material move through the gut.
4. Exercise. That daily run or walk is essential to the health of your gut as well as the rest of your physical and mental wellbeing. So it’s important that you do something mildly strenuous every day. Exercise gets your blood circulating, and the mechanical action of bouncing up and down helps move things through the gut too.
5. Limit refined carbohydrates, processed, fried and high sugar foods. These can lead to an imbalance of bacteria in the gut.

What should I do next?

• Eat a wide range of vegetables and fruit – these contain insoluble fibre that feed healthy gut bacteria and have anti-inflammatory properties that benefit your immune system
• Add fermented foods and drinks to your diet. Good sources include live yoghurt, kefir, sauerkraut, kimchi and kombucha.
• Sit down and take time to appreciate and chew your food - this benefits your gut bacteria and helps digestion.

Reviewed by: Hemal Shah, Lead GP, Livi