UNDERSTANDING PROBIOTICS: your guide to gut health

Heard of probiotics but unsure if they’re right for you? Professor Kerryn Phelps and her daughter, dietician and nutritionist Jaime Rose Chambers, explain gut health, and how probiotics work and what conditions may benefit from them.

In medical practice, we are increasingly viewing the complex microscopic world inside your gut as the fantastic new health frontier. The past decade has seen a massive amount of research into the so-called “gut microbiome”, or the microscopic population of the human gut. The human gut contains potentially thousands of different species of microorganisms. Any individual person’s gut may host between 500 and 1500 species.

As we discover more and more, we are beginning to realise just how complex the interactions of these microorganisms are with the human body, particularly the brain and the immune system.

Probiotics are powerful therapeutic microorganisms that are essential to human wellbeing. They are also useful in preventing and managing some diseases, from allergy and asthma to dental decay or diarrhoea.

Low levels or an imbalance of these “good bugs” allow an overgrowth of pathogens (disease-causing bugs like dientamoeba, candida or campylobacter), which might result in gut infections and other gut diseases.

Not all organisms in the gut mean you well. Probiotics change the way the immune system reacts to disease-causing microorganisms. Probiotics compete with harmful bacteria and enhance the activity of your immune system.

They can also help calm your immune system if it is overactive, and they may help restore or maintain a healthy balance of bacteria in your gut, which can be upset by antibiotics and other medications.

The balance of organisms in the gut is ensured by adequate numbers of two main groups of probiotics: lactobacilli and bifidobacteria.

Lactobacilli primarily populate the last part of the small intestine, while bifidobacteria are found predominantly in the large intestine. Examples of types of lactobacilli include Lactobacillus casei, L. reuteri and L. rhamnosus. The bifidobacteria include Bifidobacterium longum and B. bifidum. Other probiotics include Streptococcus thermophiles and the yeast Saccharomyces boulardii.

If levels of these probiotics become too low, it allows an overgrowth of disease-causing organisms, which may result in dysbiosis, and abnormal gut function.

Each probiotic strain has unique actions and properties, so you need to be advised on the right one(s) for the job you want them to do.

For good health, regular consumption of prebiotic and probiotic foods is important.

There are specific situations where taking high-dose targeted probiotic supplements can be beneficial. Here are some examples:

During and after treatment with antibiotics:

Even one course of antibiotics can disturb your gut flora. Increase your

dietary consumption of prebiotic and probiotic foods, and take a supplement of Saccharomyces boulardii (not if you are allergic to yeast or immune-suppressed) once or twice a day during the antibiotic course and for one week afterwards. Once the antibiotic course is finished, take a high-quality multi-strain lactobacilli/bifidobacteria combination probiotic supplement for four weeks.

Before you travel to developing countries:

Pre-dosing for two weeks with a heat-stable form of saccharomyces boulardii and taking it during travel will help to prevent and treat traveller’s diarrhoea.

Complementing allergy treatment:

Lactobacillus rhamnosus LGG can help reduce allergic responses. It’s also recommended in the third trimester of pregnancy and during breastfeeding to reduce the likelihood of asthma, eczema and allergies in newborns.

Irritable or inflammatory bowel conditions:

Lactobacillus plantarum 299v: calms the symptoms of irritable bowel syndrome (IBS), reduces non-specific bloating, wind, diarrhoea and constipation. Can help to relieve inflammation in the gut from Crohn’s disease and colitis.

Babies with colic

Lactobacillus reuteri has been shown to reduce daily crying time in babies with colic. Treatment of rotavirus diarrhoea with L. reuteri in children significantly shortens the duration of the illness (although in Australia children are routinely vaccinated against this virus).