💊 What it does
Probiotics are live microorganisms that, when taken in adequate amounts, confer a health benefit on the host. They support and restore the gut microbiome — the complex ecosystem of bacteria, yeasts, and other microorganisms living in the digestive tract. A healthy microbiome influences digestion, immune function, mental health (the gut-brain axis), inflammation, and even body weight regulation. The most well-studied probiotic strains are Lactobacillus and Bifidobacterium species.
👤 Who needs it
People recovering from a course of antibiotics — antibiotics indiscriminately kill gut bacteria and probiotics help restore the microbiome. Those with irritable bowel syndrome (IBS) — evidence supports specific strains for bloating, gas, and altered bowel habits. People with recurrent digestive issues. Anyone who has undergone gut surgery or has inflammatory bowel conditions (under medical supervision). Travellers prone to digestive upset.
🥦 Food sources first
Fermented foods are the best food-based source of beneficial bacteria: live yoghurt (dairy or plant-based), kefir, sauerkraut, kimchi, tempeh, miso, kombucha. These provide diverse bacterial strains alongside fibre and nutrients that supplements do not. A diet high in plant fibre (the prebiotic that feeds beneficial bacteria) is more fundamentally important for microbiome health than any probiotic supplement.
🗓 When to supplement
After a course of antibiotics. When experiencing persistent digestive symptoms. As a short-term intervention during travel or periods of dietary disruption. The evidence for long-term daily probiotic supplementation in healthy people with good dietary fibre intake is weaker than commonly believed.
🏷 Best form to look for
Strain matters — different strains have different evidence bases for different conditions. Lactobacillus rhamnosus GG and Saccharomyces boulardii have the strongest evidence for antibiotic-associated diarrhoea. Bifidobacterium infantis has evidence for IBS. Spore-based probiotics (Bacillus strains) are more heat-stable. Higher CFU counts are not necessarily better — strain specificity matters more.
⏰ When to take it
Take 30 minutes before a meal or with a cool drink — stomach acid is lower before meals and many strains are sensitive to acid. Some enteric-coated products can be taken with meals. Store as directed — many strains are sensitive to heat and moisture.