Optimising Gut Flora for Immunity, Hormones, and Healthy Ageing

Most people only think about their stomach when it hurts or feels bloated. However, the tiny microbes living in your gut do much more than help digest food. They play an important role in many areas of health, including immune function, metabolism, and communication with the brain. Learning more about them can help you better understand and support your long-term health.

Checking your gut bacteria helps you understand how to keep your immune system strong, balance your hormones, and protect your body as you get older.

• Why do I need to test my gut if it does not hurt? A gut test may provide useful information about your gut microbiome, even if you do not currently have symptoms.

• Can gut bacteria help support the immune system? Yes, gut microbes play an important role in supporting and training the immune system.

• Do gut bacteria affect hormones? Gut bacteria may influence hormone-related processes in the body, which can in turn affect areas such as skin, energy, and overall health.

You should test your gut flora for healthy ageing because microbial diversity naturally declines as we get older[1], leading to a loss of protective keystone species like Bifidobacterium, which then increases the risk of chronic inflammation and metabolic disorders.

When you are young, you usually have lots of different types of microbes. This is called high microbial diversity.

To learn the basics of how this works, you can read our guide: What is your gut microbiome?

As you get older, the balance of microbes in the gut can change. Some beneficial microbes may become less abundant, while others may increase. These changes may be linked to inflammation and can affect areas such as metabolism and overall health.

Taking a gut flora test gives you a map. It may show which beneficial microbes are present at lower levels, helping guide food choices that support gut health over time.

Gut bacteria affect the human immune system by interacting with immune cells in the gut-associated lymphoid tissue, known as GALT. Beneficial microbes help support immune balance, promote appropriate responses to pathogens, and may help regulate unwanted immune activity.

A large proportion of the immune system, about 70 percent, is associated with the gut. GALT plays an important role in monitoring substances in the digestive tract and coordinating immune responses.

The GALT acts as an important site for immune education and regulation. 

• Beneficial gut microbes help immune cells recognise potential pathogens and support appropriate immune responses.

• They may also help reduce unnecessary immune activation and support tolerance, helping the immune system respond without targeting the body’s own healthy tissues.

When the gut microbiome is well balanced, it can help support normal immune function. Changes in the microbiome may influence immune regulation and overall health. You might catch colds very easily or feel tired all the time. Using a gut microbiome test may help show whether beneficial microbes linked to immune support are present at lower levels.

A gut health test may provide useful information about your gut microbiome, which is increasingly being studied for its role in hormone-related processes, including oestrogen metabolism.

Hormones are chemical messengers that help regulate many functions in the body. Oestrogen is one of the key hormones involved in areas such as bone health, reproductive health, and mood. 

• After oestrogen is processed by the liver, it passes into the intestine, where some gut microbes may influence what happens to it next.

• The estrobolome refers to gut microbial functions involved in oestrogen metabolism.

• Some gut microbes may affect whether oestrogen metabolites are more likely to be excreted or reabsorbed.

This means that changes in the gut microbiome may be associated with hormone-related symptoms in some people. This can cause heavy periods, bad skin, and mood swings. You can read more about this in our specific guide on Hormonal Health and Your Microbiome.

To test gut health properly means looking at microbiome patterns that may offer early insights into gut balance, helping guide diet and lifestyle choices that support areas such as sleep, mental clarity, and immune health.

Many people in the UK use gut biome testing services because they want to upgrade their daily lives. Fixing your gut bacteria can give you more energy and make your mind much sharper. In fact, your gut bacteria talk directly to your brain constantly. You can discover exactly how this works in our Gut-Brain Connection guide.

When you look after your microbes, they look after you.

Yes. Finding out which beneficial bacteria are present at lower levels may help guide food choices that support gut and immune health before cold season starts.

They are completely safe. It is a simple stool swab collected from toilet paper done in your own bathroom. It is a convenient way for older adults to learn how to protect their health.

Yes, they can. Your microbes produce happy chemicals that travel to your brain. If your hormones and brain chemicals are balanced by a healthy stomach, you will feel much better.

“When we talk about the microbiome, we have to look beyond digestion. The gut microbiome is closely linked to immune function, healthy ageing, and hormone-related processes, including systems such as the GALT and the estrobolome. If you are experiencing frequent infections or hormonal changes, gut health may be one factor to consider. By taking a high-quality gut flora test, we can gather more detailed information about your microbiome. We can then look at beneficial bacteria such as Bifidobacterium and use this information to guide a personalised food plan that supports your health at every stage of life.”

[1] Fart F, Rajan SK, Wall R, Rangel I, Ganda-Mall JP, Tingö L, Brummer RJ, Repsilber D, Schoultz I, Lindqvist CM. Differences in Gut Microbiome Composition between Senior Orienteering Athletes and Community-Dwelling Older Adults. Nutrients. 2020 Aug 27;12(9):2610. doi: 10.3390/nu12092610. PMID: 32867153; PMCID: PMC7551621.

Wiertsema SP, van Bergenhenegouwen J, Garssen J, Knippels LMJ. The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies. Nutrients. 2021 Mar 9;13(3):886. doi: 10.3390/nu13030886. PMID: 33803407; PMCID: PMC8001875.