Why Your Gut Health Is the Cornerstone of a Strong Immune System

In times of health uncertainty, one of the best things you can do is prioritise your wellbeing—and at the heart of that is your immune system. While many people reach for immune-boosting supplements or focus on rest and hydration during cold and flu season, one critical piece of the puzzle is often overlooked: your gut.

It might come as a surprise, but around 70–80% of your immune system resides in your gut lining. That means your gut isn’t just digesting food—it’s also your body’s first line of defence. If your gut isn’t functioning well, your immune system may be underperforming too.

The Gut–Immune System Connection

Your gut is home to approximately 100 trillion microorganisms, collectively known as your gut microbiota or microbiome. This bustling ecosystem of bacteria, fungi, and other microbes plays an enormous role in your overall health—not just digestion, but also immunity, metabolism, and even brain function.

A well-functioning microbiome acts like a personal army, helping your body to:

• Break down and absorb nutrients from food
• Prevent harmful pathogens from taking hold
• Regulate inflammation
• Strengthen immune responses
• Maintain the integrity of the gut lining

The connection between your gut and your immune system is so significant that many researchers now refer to the gut as the “second brain” of the body—not because it thinks, but because of how crucial it is in regulating the body’s internal systems.

How a Poor Gut Can Weaken Your Immune Defences

If your gut health is compromised—due to things like a poor diet, chronic stress, overuse of antibiotics, lack of sleep or low fibre intake—it can lead to an imbalance in your gut flora, known as dysbiosis. This imbalance affects the structure and function of the gut lining, leading to increased inflammation, leaky gut, and weakened immune surveillance.

When this happens, you're more likely to experience:

• Frequent colds or flu
• Slower recovery from illness
• Digestive issues like bloating or constipation
• Increased food intolerances
• Low energy levels or mood swings

Essentially, if your gut is out of balance, your body becomes more susceptible to illness—and those illnesses may hit harder and last longer.

The Microbiome: Your Personal Defence System

Your gut microbiome doesn’t just passively sit by. It actively defends your body in several ways. One of its key functions is to interact directly with viruses and harmful bacteria, blocking them from taking hold and spreading in the body. Additionally, it works behind the scenes by influencing immune cells and promoting anti-inflammatory responses when needed.

A diverse and thriving gut microbiome can help:

• Increase antibody production
• Promote efficient T-cell function
• Control systemic inflammation
• Encourage rapid immune responses

This diversity is key. The more types of beneficial bacteria you have, the more resilient your gut (and immune system) will be. It’s like having a well-trained, multi-skilled security team on duty 24/7.

How to Support a Healthy Gut—and a Stronger Immune System

The good news is that there are simple and effective ways to support your gut microbiota and, in turn, your immune system. Here’s where to start:

1. Eat More Fibre-Rich Foods

Plant-based foods like legumes, fruits, vegetables, whole grains, and nuts contain prebiotic fibre that feeds your good gut bacteria and helps them flourish.

2. Include Fermented Foods in Your Diet

Foods like yoghurt, kefir, kimchi, sauerkraut, miso, and kombucha are rich in probiotics—live bacteria that contribute to a more balanced gut ecosystem.

3. Stay Hydrated

Water supports the mucosal lining of the intestines and helps transport nutrients throughout the body, making it easier for your gut to do its job.

4. Limit Processed Foods and Added Sugar

Highly processed foods and excess sugar can feed harmful bacteria, encouraging dysbiosis and inflammation.

5. Manage Stress

Chronic stress can significantly disrupt your gut microbiome. Try mindfulness, meditation, regular movement, or simply spending time in nature.

6. Prioritise Sleep

Aim for 7–9 hours of quality sleep each night. Your gut and immune system both depend on restorative rest to function properly.

Consider a Gut Health Supplement

If you're finding it hard to get enough probiotics or prebiotics from food alone—or if your lifestyle has been especially taxing—consider a high-quality gut health supplement. Look for one that supports both microbial diversity and immune response, preferably with clinically backed strains and gut-soothing ingredients.

How do you achieve an abundant and diverse microbiome aka a strong immune system?

Feeding the gut bacteria a diverse diet, rich in foods containing prebiotics will achieve an abundant and diverse microbiome. Prebiotics are a food that the gut bacteria feed on enabling them to grow and multiply

Prebiotics are found in these foods:

• Onion, leek and garlic
• Jerusalem artichoke
• The skin of apples (pectin)
• Chicory root
• Beans
• Red and black rice

What about probiotics?

Probiotics can be very useful, especially in addressing specific conditions and some can also help to increase the diversity of the microbiome. However, prebiotics are actually the go to when trying to enhance overall diversity of your gut microbiome. Saccharomyces boulardii, one of the most researched probiotics available, can be useful in boosting the immune system if you need the extra help and can also survive the stomach acid making it a superior probiotic. 

What reduces the good bacteria and decreases the diversity?

Modern living is not kind to our gut environment because we are living in a world where processed foods are part of our diet and stress is very common. Below is a list of the worst offenders:

• Stress
• processed foods
• GMO produce
• Alcohol
• Pesticides (non-organic produce)
• Medications especially antibiotics
• Gluten

 It's worth mentioning that antibiotics have a noticeable, lasting effect on the composition of the microbiome, and should only be used when absolutely necessary. If you have to take antobiotics make sure you rebuild you microbiome using pre and probiotics. 

Most of us are putting our gut microbiome at risk every day, but we can mitigate this by regularly feeding the good bacteria in the gut with prebiotics. It takes a lot of the above foods to achieve the required effect and these foods should be consumed on a daily basis, which most people are unable to do.

Therefore, including a daily prebiotic supplement is the best way to ensure your good bacteria are looked after, so they can look after your immune system.

Are there any side effects?

There are many varieties of prebiotics on the market and some are more gentle than others. The prebiotics I recommend are unlikely to cause symptoms such as bloating and gas. Make sure the prebiotics are FODMAP safe and have the FODMAP tick. I always recommend starting on a low dose and increase gradually, as with all fibre, your gut needs time to adjust. It's also advisable to increase water intake when you increase the intake of fibre.

Prebiotics have many other benefits to your health such as helping weight loss, decreasing inflammation and possibly help regulate hormones.

FEED contains FODMAP friendly prebiotics in clinically trialled dosages as well as probiotics to enrich your microbiome and enhance your overall health.

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