Understanding the gut microbiome 

Trillions of microbes live inside the human body, with the majority of them being found inside your intestines. This colony of microorganisms in the gut is known as the gut microbiome. 

With more than 40 trillion bacterial cells in your body—compared to 30 trillion human cells—they play a significant role in maintaining our overall health.

While there is a lot we still don’t understand about the gut microbiome, it has been shown that it influences many bodily functions, most notably digestion. 

It also affects many other aspects of health, including the immune system.

How the gut microbiome affects the immune system

While it’s commonly known that most of the microbiota live in the gut, a large percentage of the body’s immune system also resides in the gut. 

With around 70-80% of our immune system found in the gut, there is a symbiotic relationship between the gut microbiome and the immune system, as they’ve evolved to coexist to ensure that the body is protected. 

Their interactions with each other begin practically as soon as we are born, as the birth canal contains a large number of bacteria. 

As we grow, the gut microbiome and immune system support one another, communicating with each other to help with various bodily functions while nurturing a healthy body. 

When there are abnormalities in the way they communicate with each other, it can contribute to disease. For instance, if there are changes in the natural balance of the gut microbiome due to a poor diet, antibiotics, surgeries, heavy metals etc, this lowers your intestinal flora, which may lead to suppressed immunity

How can microbiome cancer treatment help with immunotherapy

While research on the link between microbiome cancer treatment and the efficiency of immunotherapy is still in the early stages, there are some promising results. 

Studies on mice have shown that the composition of their gut microbiome impacts both the size and number of liver cancer tumours. 

Meanwhile, studies with human volunteers also found some encouraging associations. 

In a study conducted by King's College, London, results have shown that the effectiveness of immunotherapy treatment for people with skin cancer improved in those with a more diverse microbiome.

Another study found that patients who underwent a bone marrow or stem cell transplant were more likely to be alive after 3 years if they had a more diverse gut microbiome.

What these studies show is that while there hasn’t been conclusive evidence, microbiome cancer treatment does seem like it could improve the effectiveness of immunotherapy, especially when considering its link with our immune system. 

What does microbiome treatment for cancer involve?

A microbiome treatment for cancer involves restoring the balance of the gut microbiome.

You can consult with your doctor and take a gut microbiome test if you want to learn more about your gut microbiome and the best ways to keep your gut microbiome balanced.

The general way of restoring gut microbiome balance is by reducing the amount of sugar, high-fat and processed food items you eat. Instead, you could follow a more balanced diet that includes a diverse range of food items, including:

  • Foods high in fibre such as a variety of vegetables and fruits
  • Fermented foods like yoghurt, kimchi, or saukraut
  • Whole grains such as whole-grain bread or pasta
  • Food rich in polyphenols like dark chocolate, red wine, or green tea
food items

While you may be tempted to change your diet to improve your health, remember to always consult a medical professional before making any significant changes to your diet.

Outside of diet, it’s recommended that you get a sufficient amount of sleep, keep your stress levels low, and stay hydrated throughout the day to keep your microbiome balanced. 

Consult a gastrointestinal specialist

Dr Suhirdan Vivekanandarajah is a Sydney-based gastroenterologist and hepatologist.

His extensive knowledge of the gut can help you with determining whether microbiome cancer treatment would be suitable for you or your loved ones. 


To find out more, schedule a consultation with him today.