What's Your Gut Telling You?

Updated May 2023

Recent research has revealed how our gut “bugs” or bacteria can influence our long term health and can contribute to our overall health and wellbeing. Dietitian Laura Vincent explores some of the research, and tells us which foods can help to help maintain good gut health.

Gutsy bacteria

Your intestine, or also referred to as the gut, is home to tens of trillions of bacteria, weighing nearly 2kg. This community of bacteria, which contains a mixture of 'good' and 'bad' bacteria, is known as our 'microbiome'. We evolved together with our microbiome over millions of years. One third of our gut bacteria is common to most people, while two thirds are specific to each one of us. Essentially, your microbiome is like an individual ID card.

Recent research has discovered that small changes in this finely balanced community can affect our immune system, metabolism, body weight, and mood.

Let’s have a look at how the good bugs work to keep you healthy:

How good bacteria keep you well

They remove “bad bacteria”. They get rid of the nasty bacteria that enter the digestive tract, preventing them from multiplying and making us unwell. “Good” bacteria produce lactic acid and fatty acids which lowers the acidity in the large bowel, making it difficult for “bad” bacteria to over-multiply. This helps keep a healthy balance of bacteria.

They aid digestion. Good bacteria break down fibre in the gut to produce nutrients for the cells that line the bowel, keeping your gut healthy.

They make vitamins. You get most of your vitamins from food, but the healthy bacteria in our body make some too, such as certain B vitamins and vitamin K.

They attack infections. Around 70 per cent of our immune system is in our digestive system. When we have a virus. Our healthy bacteria leap into action, aiming to neutralise toxins that the virus makes, thus reducing the likelihood that the virus will progress.

Is there a link with bacteria and arthritis?

A study published in 2013 in the U.S. found that people with rheumatoid arthritis were much more likely to have a bug called Prevotella copri present in their gut than people that did not have the disease. Another study, completed in 2014, found that patients with psoriatic arthritis had significantly lower levels of other types of gut bacteria.

These findings suggest that certain bacteria may be linked to triggering the autoimmune response that leads to joint inflammation. Studies have also found that ‘leaky gut syndrome’, or other gastrointestinal problems, could trigger flare ups in conditions such as rheumatoid arthritis and lupus.

What is a "leaky" gut?

The inside of the intestine is lined by a single layer of cells that make up the mucosal barrier. This barrier is effective at absorbing nutrients, but prevents most large molecules and germs passing from inside the intestine into the bloodstream and potentially causing widespread symptoms.

In some circumstances, when an imbalance of good and bad bacteria has resulted in a poor diet, or overuse of antibiotics, this barrier can become less effective by making the gut "leaky", although this in itself is not generally thought to be sufficient to cause serious problems. While there is currently little evidence to back up the theory of ‘leaky gut syndrome’ it is still important to maintain good gut health to keep your immune system strong.

How do I take better care of my gut health?

Gut health is influenced by our genes, and while we can’t change our inherited genes, we can change our unique digestive system. We can do this by taking a look at what we’re eating and include more of the foods which help keep our good bacteria thriving.

Eat a healthy, high-fibre, balanced diet. 

A diet which is healthiest for our body is likely to be healthiest for the good bacteria in our gut too. Meals should be based on wholegrain and plant foods such wholemeal grainy bread, brown rice and a wide range of brightly coloured vegetables and seeds/nuts. The latest research also recommends that animal fat (saturated fat) is to be kept low by including lean meats in your meals, for example, using extra lean mince rather than wagyu beef. Don’t forget that legumes and pulses such as chick peas and lentils make a great meat replacement and are very beneficial for our gut bacteria.

Rebalance with probiotics (the good bacteria)

Probiotics are strains of healthy bacteria that can help balance out “good” and “bad” bacteria in the gut. There are many food items containing probiotics, such as yoghurts and drinks, as well as a variety of probiotic supplements. Look for the words lactobacillus and bifidobacteria on food labels.

Take antibiotics only when necessary

If your doctor has prescribed antibiotics it is important that you follow this advice. However, antibiotics can cause an upset in the balance of “good” and “bad” bacteria. So when you’re on a course of antibiotics, consider taking a daily probiotic supplement and continue to take them for a month afterwards.

Go with your gut feeling

While more research is required to provide us with more evidence to link gut health and arthritis, adopting a healthy diet and adding probiotics into your daily eating routine can’t hurt your gut health. It may in fact help you feel better overall. If you need support and guidance with your diet, it is a good idea to consult an Accredited Practising Dietitian (APD). An APD will help to ensure you are receiving adequate nutrition to maintain good health. Visit the Dietitians Association of Australia website: www.daa.asn.au  to find an APD near you.


Conlon MA et al. (2014) The Impact of Diet and Lifestyle on Gut Microbiota and Human Health. Nutrients. 2015, 7, 17-44.

Eckberg PB et al. (2005) Diversity of the human intestinal microbial flora. Science. 308: 1635-1638.

Floch MH (2014) Probiotics and Prebiotics. Gastroenterology & Hepatology, 2014 Oct; 10 (10):680-1.

Scher JU et al. (2013) Expansion of intestinal Prevotella copri correlates with enhanced susceptibility to arthritis. Elife. 2013 November; 5;2.

Scher JU et al. (2015) Decreased bacterial diversity characterizes the altered gut microbiota in patients with psoriatic arthritis, resembling dysbiosis in inflammatory bowel disease. Arthritis Rheumatology. January; 67(1):128-39.

Stewart A (2009) Leaky Gut Syndrome. Foods Matter, 2009 Feb: 8-9.