Get Regular Updates!
Search
|The amazing influence of gut microbes in our immune system

Food

image|

Shutterstock

Bacteria pattern

The amazing influence of gut microbes in our immune system

Could autoimmune and allergic conditions like Crohn’s disease, multiple sclerosis or type 1 diabetes one day be treated with microbes in your gut?

The amazing influence of gut microbes in our immune system

Inside your gut is a collective of bacteria, fungi and viruses known as the gut microbiota.

Amazingly, they start to develop immediately after we’re born. With our mother’s bacteria quickly colonising our body and gut, within weeks, our gastrointestinal tract is loaded with microbes.

This vast community of microorganisms live in our body and are critical for how parts of our bodies operate. In fact, these microorganisms are so important they are as prominent in our body as our own cells.

A gut full

When it comes to our gut, the microbiota is mostly made up of bacteria, although there are also fungi and viruses.

Our gut contains billions of these bacterial cells at any one time, and one of their jobs is to produce essential vitamins our body can’t make, like B1 through to B12, folate, vitamin K and thiamine.

Another important function of these microbes is their influence on the immune system. This is the body’s first line of defence against infections. The immune system also keeps us healthy by eliminating our own cells when they become diseased.

In recent years, the microbes in our gut have been the focus of intense research. What has emerged are strong connections between our health and the presence or absence of specific groups of gut microbes.

Gut microbes and the immune system

Sarkis Mazmanian is Professor of Microbiology at the California Institute of Technology. He’s been studying how gut microbes affect our health for over 15 years.

View Larger
Image|Professor Sarkis K. Mazmanian
Artistic depiction of gut microbes

“Gut microbiota in people varies between individuals,” says Sarkis.

“A new concept has emerged in biomedicine that the balance of different bacterial species in the gut can influence whether the immune system becomes activated or not.”

“This is important, because an overactivated immune system can result in tissue damage and symptoms over time,” he adds.

“[It’s] believed to underlie the cause of many autoimmune, inflammatory and allergic disorders in humans.”

Sarkis believes colonisation with bacteria with anti-inflammatory properties may prevent or even treat many diseases in the future.

Friend or foe?

At the core of an effective immune system is a delicate chemical balance that helps immune cells identify friends from foes. Gut bacteria are important players in this balance. They take the fibre you eat and digest it, turning it into smaller molecules.

Video|Armando Hasudungan with CSIRO
Human Gut Microbiome

One group of these molecules are short-chain fatty acids (SCFAs), a crucial part of our gastrointestinal health. SCFAs can influence a range of cells and functions within the body, leading to changes in the immune function of the gut.

These SCFAs also influence another important immune cell – regulatory T cells.

T cells are the immune system’s informants, telling your body how to respond to invading pathogens or germs.

SCFAs produced by gut bacteria interact with T cells and can influence their behaviour, directing them to attack or spare cells.

Immune system overdrive in type 1 diabetes

Gut microbiota has also been linked to type I diabetes, an autoimmune disease affecting more than 150,000 Australians.

This condition stops the body from producing enough insulin because its own immune system is attacking the pancreatic cells in charge of this task.

In one study, researchers fed mice a number of special diets that were fermented by gut microbes. Dependent on the diet, this led to the production of large amounts of either acetate or butyrate, two common SCFAs produced by gut bacteria. These SCFAs appeared to protect the mice from diabetes.

“What was remarkable about this study was [these] SCFAs protected from diabetes at so many levels,” says Charles Mackay, Professor of Immunology at Monash University.

SCFAs also influence another complex aspect of our biology – our epigenome.

The epigenetic link

Silently working alongside our genome, the epigenome is a vast repertoire of chemical tags placed on DNA molecules that regulate the function of many genes.

Called epigenetic modifications, these chemicals function almost like a coat. When they’re placed on parts of the DNA or associated proteins, they influence their function.

A direct consequence of epigenetic modifications is that genes can be turned on or off, and studies have shown that SCFAs can influence these modifications.

In a 2016 study, researchers found that feeding mice with a Western diet – rich in fat and sugar but poor in fibre – had epigenetic consequences. These mice showed significantly lower levels of Bacteroidetes and a greater amount of Firmicutes (two common type of gut bacteria) compared to mice fed a fibre-rich diet.

“SCFAs, particularly butyrate, can influence the expression of certain genes that have a big impact on biology,” explains Charles.

Other studies have established a link between the gut microbiota, epigenetics and the occurrence of conditions like inflammatory bowel diseases, immune problems and even cancer.

Video|Harvard Medical School
Our Microbes, Ourselves: Gut bacteria’s key role in immunity is tuned to the host species

Our unique microbiome

We know it’s important to keep our gut healthy, but one of the biggest challenges is yet to be solved – how do we do it?

“The current state of the art in microbiome research does not provide widely validated ways to improve your microbiome,” says Charles.

“This is largely because more work needs to be done, but also there is likely not going to be a one-size-fits-all intervention.”

Nevertheless, some sure ways to improve the health of your gut and the rest of your body is to eat a healthy diet, rich in fibre and low in fat, sugar and processed foods, as explained by the CSIRO. Also, exercising and sleeping well are a sure way to improve your gut and overall health.

We love science puns VIDEO

Republish

Creative Commons Logo

Republishing our content

We want our stories to be shared and seen by as many people as possible.

Therefore, unless it says otherwise, copyright on the stories on Particle belongs to Scitech and they are published under a Creative Commons Attribution-NoDerivatives 4.0 International License.

This allows you to republish our articles online or in print for free. You just need to credit us and link to us, and you can’t edit our material or sell it separately.

Using the ‘republish’ button on our website is the easiest way to meet our guidelines.

Guidelines

You cannot edit the article.

When republishing, you have to credit our authors, ideally in the byline. You have to credit Particle with a link back to the original publication on Particle.

If you’re republishing online, you must use our pageview counter, link to us and include links from our story. Our page view counter is a small pixel-ping (invisible to the eye) that allows us to know when our content is republished. It’s a condition of our guidelines that you include our counter. If you use the ‘republish’ then you’ll capture our page counter.

If you’re republishing in print, please email us to let us so we know about it (we get very proud to see our work republished) and you must include the Particle logo next to the credits. Download logo here.

If you wish to republish all our stories, please contact us directly to discuss this opportunity.

Images

Most of the images used on Particle are copyright of the photographer who made them.

It is your responsibility to confirm that you’re licensed to republish images in our articles.

Video

All Particle videos can be accessed through YouTube under the Standard YouTube Licence.

The Standard YouTube licence

  1. This licence is ‘All Rights Reserved’, granting provisions for YouTube to display the content, and YouTube’s visitors to stream the content. This means that the content may be streamed from YouTube but specifically forbids downloading, adaptation, and redistribution, except where otherwise licensed. When uploading your content to YouTube it will automatically use the Standard YouTube licence. You can check this by clicking on Advanced Settings and looking at the dropdown box ‘License and rights ownership’.
  2. When a user is uploading a video he has license options that he can choose from. The first option is “standard YouTube License” which means that you grant the broadcasting rights to YouTube. This essentially means that your video can only be accessed from YouTube for watching purpose and cannot be reproduced or distributed in any other form without your consent.

Contact

For more information about using our content, email us: particle@scitech.org.au

Copy this HTML into your CMS
Press Ctrl+C to copy

We've got chemistry. Want something physical?