Probiotics are everywhere — in yoghurt, kombucha, capsules, powders, and even chocolate bars. Over the last 15 years, probiotic products have exploded onto the market. With so many options, it’s hard to know whether you actually need one, which type to choose, and whether a supplement is better than food.

The short answer: it depends on your situation. Probiotics can be helpful for specific conditions — but they’re not a one-size-fits-all solution, and they’re definitely not a replacement for a balanced diet.

This guide breaks it down in plain English.

What Are Probiotics?

Probiotics are live microorganisms — mostly bacteria and some yeasts — that provide health benefits when consumed in adequate amounts. Probiotic bacteria colonise your gut and support the balance of your gut microbiome, which contains trillions of microorganisms that influence digestion, immune function, and even mood.

Not all probiotics are the same. Different strains produce different effects in the body. A probiotic that helps with antibiotic-associated diarrhoea may do nothing for bloating. A strain that supports IBS symptoms may not be relevant for someone with ulcerative colitis. Strain specificity matters — and it’s one of the main reasons generic “gut health” supplements often disappoint.

Which Probiotic Strains Have Evidence Behind Them?

The World Gastroenterology Organisation has reviewed hundreds of studies on specific probiotic strains and their effects on particular conditions. Based on this research, here are some of the strains with the strongest evidence — and where you can find them in Australia.

Irritable bowel syndrome (IBS)

Bifidobacterium bifidum, Lactobacillus plantarum, and Bifidobacterium infantis have shown improvements in IBS symptoms including abdominal pain, bloating, and irregular bowel habits. Available in products like Life Space Triple Strength Probiotic and NOW Clinical GI Probiotic.

If IBS is affecting your eating, a dietitian trained in the low FODMAP diet can help you manage symptoms alongside — or instead of — probiotic supplementation. Accelerate Nutrition’s dietitians have completed further training from Monash University in using the low FODMAP diet for IBS. For practical gut tips beyond probiotics, our guide on gut-friendly food support covers fibre, hydration, stress, and meal timing.

Antibiotic-associated diarrhoea

Lactobacillus rhamnosus GG and Saccharomyces boulardii reduce the severity and duration of diarrhoea caused by antibiotic use. Antibiotics kill both harmful and beneficial gut bacteria, disrupting the microbiome balance. A targeted probiotic taken during and after an antibiotic course can help restore beneficial populations more quickly.

Available in products like NOW Saccharomyces Boulardii, Life Space Double Strength Probiotic, and Farmer’s Union Greek Style Yoghurt (which contains Lactobacillus casei DN-114 001, Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, and Lactobacillus casei).

Take probiotic supplements 2–3 hours apart from your antibiotic dose to avoid the antibiotic killing the probiotic bacteria before they reach the gut.

Ulcerative colitis (maintenance of remission)

Escherichia coli Nissle 1917 has evidence for maintaining remission in ulcerative colitis. Available in Australia as Mutaflor. This is a condition-specific recommendation — always discuss with your gastroenterologist or dietitian before starting.

Uncomplicated diverticular disease

Lactobacillus casei has shown improvements in symptoms of uncomplicated diverticular disease. Available in Life Space Double Strength Probiotic.

Probiotic Foods vs Supplements — What’s the Difference?

Fermented foods contain naturally occurring probiotic cultures. These include yoghurt, kefir, sauerkraut, kimchi, miso, tempeh, and kombucha. Fermented foods provide beneficial bacteria alongside other nutrients — protein and calcium from yoghurt, B vitamins from tempeh, or antioxidants from kimchi.

Probiotic supplements contain specific, standardised strains at known doses, measured in colony forming units (CFU). Supplements are regulated in Australia by the Therapeutic Goods Administration (TGA) as complementary medicines. Food products containing probiotics are regulated by Food Standards Australia New Zealand (FSANZ) — but unlike supplements, food labels don’t always have to disclose the number of live bacteria per serve.

For most people, starting with probiotic-rich foods is a practical first step. A daily serve of natural yoghurt or kefir introduces beneficial bacteria while also providing protein, calcium, and other nutrients. Supplements become more relevant when you’re targeting a specific condition with a specific strain — or when food sources alone aren’t providing enough of the right bacteria.

If you’re exploring the broader question of food versus supplements, our guide on why real food comes first covers the evidence across multiple nutrient types.

Don’t Forget the Prebiotics

Probiotics need fuel. Prebiotics are non-digestible fibres that feed beneficial gut bacteria and support their growth. Without adequate prebiotics, probiotic bacteria — whether from food or supplements — struggle to establish themselves in the gut.

Prebiotic-rich foods include onions, garlic, leeks, asparagus, bananas (especially slightly underripe), oats, barley, legumes, and Jerusalem artichokes. These foods contain fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), and inulin — specific types of prebiotic fibre that selectively feed beneficial bacteria like Bifidobacterium and Lactobacillus species.

A diverse diet rich in plant-based foods supports a diverse gut microbiome. Research from the American Gut Project suggests aiming for 30 different plant foods per week — including vegetables, fruits, legumes, nuts, seeds, whole grains, herbs, and spices — to optimise microbiome diversity.

If you’re following a low FODMAP diet for IBS, some prebiotic foods (particularly garlic, onion, and wheat) will be restricted during the elimination phase. Your dietitian can help you identify which prebiotics you tolerate and reintroduce them safely during the challenge phase.

When Probiotics Might Not Be Right for You

Probiotics are generally considered safe for most healthy people. However, certain groups should exercise caution:

  • People with compromised immune systems — including those on immunosuppressant medications, people undergoing chemotherapy, or those with critical illness — should consult their doctor before taking probiotics. In rare cases, probiotic bacteria can cause infection in immunocompromised individuals.
  • People with small intestinal bacterial overgrowth (SIBO) may find that certain probiotics worsen bloating and gas. A dietitian can help determine the right approach for your situation.
  • Probiotic supplements are not regulated as strictly as pharmaceutical medications. Quality varies between brands. Look for products that name the specific strain (not just the genus and species), state the CFU count at the end of shelf life (not just at manufacture), and are stored according to label instructions.

How to Decide — A Practical Framework

Ask yourself these questions:

Do I have a specific gut condition? If yes — IBS, antibiotic-associated diarrhoea, ulcerative colitis, or diverticular disease — the research supports specific strains for specific conditions. Talk to your dietitian about which strain matches your situation.

Am I eating fermented foods regularly? If not, starting with a daily serve of yoghurt or kefir is a simple, low-risk way to introduce beneficial bacteria alongside other nutrients.

Am I eating enough prebiotic fibre? Probiotics work better when supported by a diverse, fibre-rich diet. Focus on the food foundation first.

Am I looking for a general health boost? The evidence for probiotics as a general wellness supplement is less clear-cut than the condition-specific evidence. A gut health dietitian at Accelerate Nutrition can help you assess whether a probiotic is likely to make a difference — or whether dietary changes alone will get you where you want to be.