Gut & microbiome
Supplements for your gut and microbiome: live cultures, prebiotic fibres such as inulin, and digestive enzymes. We explain which forms reach the gut, what a sensible dose looks like and how long to give it.Read more →
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How live cultures, prebiotic fibre and enzymes differ
Your gut is home to a large community of bacteria, usually called the microbiome. Food does most of the work here. Supplements sit around that: they add live bacteria, feed the bacteria you already have, or help you break down a meal. Knowing which of the three you need saves guesswork.
Three groups with three different jobs
- Live cultures, the products most people call probiotics. The dose is given in CFU, the number of living bacteria per serving. The named strain, for example Lactobacillus acidophilus, tells you more than a large CFU figure.
- Prebiotic fibre such as inulin, FOS or psyllium husk. This is food for the bacteria already living in your large bowel, so it works with your own microbiome instead of adding to it.
- Digestive enzymes such as protease, lipase and lactase. They help break food down in the moment and do not change your bacteria.
Most people start with one group rather than all three. For a steady daily habit, live culture supplements are the usual starting point. If your diet is short on plants, feeding your own bacteria often does more than adding new ones.
Two more words appear on shelves. Synbiotics combine live bacteria with prebiotic fibres in one product, which is convenient but often means a modest amount of each. Postbiotics use heat-treated bacteria or their by-products, so they stay stable at room temperature and do not need to survive the trip through your stomach.
What a UK label may and may not say
You will rarely see the word probiotic on a British pack. Under GB nutrition and health claims rules that word counts as a health claim, and no claim for it has been authorised. So brands write live cultures and name the strains instead. Fibre is different. One authorised claim says that chicory inulin contributes to normal bowel function by increasing stool frequency, at 12 g a day. Many blends contain far less, so check the back of the pack.
How we choose what goes in this collection
We look at three things: the form, the dose and whether a combination makes sense. For live cultures we want named strains and a CFU figure guaranteed to the end of shelf life, not only at production. For fibre we look at the amount per serving, because 2 g of inulin behaves differently from 12 g. We are cautious with blends that stack ten strains and a little fibre into one small capsule, because nothing in them reaches a studied amount. Every product passes our compliance team, and we test batches ourselves alongside independent labs. You can read how we select.
Who it suits and what to expect honestly
These products suit people who want a calm daily habit, frequent travellers, and anyone rebuilding a routine after a course of antibiotics, taken a few hours apart from the medicine. Give it two to four weeks of consistent use before you judge it. Some wind in the first days is common, and fibre is best increased gradually with plenty of fluid. If you have IBS, larger amounts of fermentable fibre can feel worse rather than better, so start low and build slowly. Food stays the base here: plant variety first, supplements to fill the gaps. This goal sits in our IMMUNITY + VITALITY range, with the everyday basics most people build on.
Frequently asked questions
They work in three different ways. Live cultures add bacteria, usually strains of Lactobacillus and Bifidobacterium. Prebiotic fibres such as inulin and psyllium husk feed the bacteria already in your large bowel. Digestive enzymes help break down fats, proteins, carbohydrates or milk sugar during a meal. None of them replaces a varied diet with plenty of plants, which is what shapes your microbiome most. Start by deciding which of the three matches what you notice day to day.
Because of the rules, not the quality of the product. In Great Britain the word probiotic is treated as a health claim, and no health claim for probiotics has been authorised. Brands that follow the rules therefore write live cultures, friendly bacteria or the strain name in full. The one authorised claim in this area is narrow: live yoghurt cultures improve lactose digestion for people who struggle to digest lactose. Judging a product on named strains and dose is more useful than on the wording.
It depends on what you want the product to do. This table sets out the difference.
| Form | What it does | Suits |
|---|---|---|
| Live cultures | Adds bacteria strains | Daily routine, after antibiotics, travel |
| Prebiotic fibre | Feeds your own bacteria | Low plant intake, regularity |
| Synbiotic | Both, in one dose | Convenience over dose size |
| Postbiotic | Heat-treated bacteria | Storage without a fridge |
| Digestive enzymes | Helps break food down | Heaviness after meals, lactose |
One group at a time makes it easier to see what helps.
Fibre is the base of any gut routine, and most people in the UK fall short of the guideline. Official amounts differ by age.
| Age group | Fibre per day |
|---|---|
| 16 years and over | 30 g |
| 11 to 16 years | 25 g |
| 5 to 11 years | 20 g |
| 2 to 5 years | 15 g |
Build up gradually and drink enough fluid, because a sudden jump can cause bloating and cramps.
Source: NHS informFollow the pack, because products are made differently. Many are designed to be taken once a day with or just before a meal, since food buffers stomach acid a little. Others are made to be taken at any time. What matters more than the clock is doing it at the same moment every day, so you do not skip days. Take them with water rather than a hot drink or fruit juice, and keep a few hours between them and antibiotics.
Give it two to four weeks of daily use. Some people notice more comfort or more regular visits to the loo in the first week or two, while others feel very little, because the effect depends on the strain, the dose and your own microbiome. Judging a product after three days tells you nothing useful. If nothing has changed after about a month of consistent use, switching to a different strain or to a fibre-first approach is more sensible than adding a second product.
Yes, and it is usually short-lived. New bacteria and fermentable fibres produce gas while your gut adapts, so mild wind or a fuller feeling in the first days is common. Starting on a lower dose, or every other day, and building up over a week or two makes it easier. Drink plenty of fluid alongside fibre. If discomfort lasts beyond a couple of weeks or gets worse, stop and rethink the product rather than pushing through.
Some strains are freeze-dried and shelf-stable, others need cold storage. The pack tells you, and it is worth following, because heat reduces the number of surviving bacteria. On CFU, bigger is not automatically better. Look for two things instead: a named strain, and a CFU figure guaranteed until the end of shelf life rather than only at the time of production. A modest, well-studied dose that is still alive beats a large number measured on the factory floor.
Speak to your GP or pharmacist first if you have a weakened immune system, take immunosuppressant medicines, are seriously ill, or are considering live cultures for a baby or young child. If you are pregnant or breastfeeding, check before starting anything new. With IBS, larger amounts of fermentable fibre such as inulin and FOS can increase bloating and wind, so a low starting dose, or a non-fermentable option, is often kinder. Persistent symptoms deserve a proper assessment, not a supplement.
