Gut health supplements: fibre, probiotics and enzymes

Sauerkraut, kefir, yoghurt, oats, lentils and a sliced apple in small bowls — AI-generated illustration · NutriMetrics

Quick answer

The NHS recommends 30 g of fibre a day for adults; most people in the UK eat about 20 g. In the UK even the word "probiotic" on a label counts as a health claim, so many products say "live cultures" instead.
Fibre supplements such as psyllium are the first step for regular bowel movements; the 2023 US gastroenterology guideline suggests them for chronic constipation.
Probiotics work strain by strain. Some reduce diarrhoea linked to antibiotics; none has an authorised health claim.
Lactase is the one digestive enzyme with an authorised claim (UK and EU): it improves lactose digestion in people who have difficulty digesting lactose.
A lasting change in bowel habit, blood in the stool or weight loss needs a doctor, not a supplement.

Key numbers

UK fibre recommendation (NHS): 30 g/day; Most adults eat about 20 g.
Adequate fibre intake, adults (EFSA): 25 g/day
Lactase claim (UK and EU): 4,500 FCC units per lactose-containing meal
Authorised claims for probiotics (UK and EU): None
Bowel-function claim for chicory inulin (UK and EU): 12 g/day
Fibre supplements for constipation (ACG/AGA 2023): Suggested; Conditional recommendation, low-certainty evidence.

What these terms mean: NRV upper levels (NHS, EFSA) maximum levels by country daily dose

How to choose

Start with fibre from food (wholegrains, legumes, fruit, vegetables); most adults eat less than 25 g a day.
For psyllium, start low (a teaspoon a day) with a large glass of water, and increase over one to two weeks.
For probiotics, choose a product that names the strain (for example *Lactobacillus rhamnosus* GG) and states the CFU at the end of shelf life, matched to your problem.
If dairy gives you trouble, lactase tablets taken with the meal have an authorised claim.
Avoid long-term use of stimulant laxatives sold as "detox" or "slimming" teas (senna, cascara).

Which supplement for which digestive problem

Problem	Option with the best support	Good to know
Constipation	Psyllium or another fibre supplement	Increase slowly, with water
Loose stools or IBS	Psyllium (soluble fibre); some probiotic strains	Results vary by person and strain
Diarrhoea linked to antibiotics	Specific probiotics, started with the antibiotic	Check the strain on the label
Lactose intolerance	Lactase with the meal	authorised claim at 4,500 FCC
Bloating, heavy digestion	Artichoke extract (small trials)	Weak evidence; no authorised claim
“Detox” or “flat tummy”	Nothing with good evidence	Often stimulant laxatives; avoid long-term use

The only authorised claims for bowel function (UK and EU)

A label may only promise an effect on bowel function with one of these authorised claims, and only at the amount set for it:

Ingredient	Authorised claim	Condition
Chicory inulin	Contributes to normal bowel function by increasing stool frequency	12 g a day
Wheat bran fibre	Contributes to an acceleration of intestinal transit	At least 10 g a day, in a food high in fibre
Wheat bran fibre	Contributes to an increase in faecal bulk	Food high in fibre
Rye fibre	Contributes to normal bowel function	Food high in fibre
Oat grain fibre, barley grain fibre	Contribute to an increase in faecal bulk	Food high in fibre
Lactulose	Contributes to an acceleration of intestinal transit	10 g in a single daily serving
Activated charcoal	Contributes to reducing excessive flatulence after eating	1 g at least 30 minutes before a meal and 1 g shortly after

“High in fibre” means at least 6 g of fibre per 100 g, or 3 g per 100 kcal. The chicory inulin claim was reserved for the company that applied for it until 2021; any brand may now use it, but only at 12 g a day, which means a powder: a capsule holds less than 1 g.

What is missing from the list matters as much:

Psyllium (ispaghula), the fibre guidelines suggest first for constipation, has no authorised food claim. The European Medicines Agency recognises ispaghula husk as a herbal medicine for constipation, so you’ll find it both as a pharmacy medicine and as a supplement sold simply as “fibre”.
Probiotics have no authorised claim at all.
“Detox”, “flat tummy” or “intestinal cleanse” are not authorised claims.

The table below ranks every ingredient in our goal finder for gut and digestion by strength of evidence.

Ingredients for this goal, by strength of evidence

Ingredient	Evidence	Authorised claim (UK/EU)	What the evidence shows
Psyllium husk	Strong	No	Strong evidence for regularity (both constipation and loose stools).
Probiotic cultures	Moderate	No	Specific strains help with antibiotic-related diarrhoea and IBS symptoms.
Artichoke extract	Limited	No	Small trials on bloating and indigestion.

Products we have checked

Label data checked by NutriMetrics for products sold in Spain and Germany. UK product checks are next. Sorted alphabetically, not ranked.

Checked: 15 Oct 2026
Product	Per daily dose	Sold in	Label
Lactoflora (Stada) Lactoflora Restore1 capsule a day after a meal	Probiotic cultures: 4 bn CFU · 4 strains (NCFM, Lpc-37, Bl-04, Bi-07)	Spain	Source
OMNi-BiOTiC OMNi-BiOTiC 61 sachet (3 g) a day	Probiotic cultures: 3 bn CFU	Germany (not yet confirmed)	Source
Sunday Natural Bio Flohsamenschalen (powder)1–2 tsp (≈5 g) a day	Psyllium husk: 5 g	Germany	Source

Who should be careful

Psyllium: take it with plenty of water, and keep medicines about two hours apart, because fibre can reduce their absorption.
Serious illness or weakened immune system: don't take probiotics without medical advice.
Red flags: blood in the stool, unexplained weight loss, night-time symptoms or a change after age 50 need a medical check.

FAQ

What is the best supplement for constipation?

A soluble fibre supplement such as psyllium, taken with plenty of water, is the usual first step; the 2023 US gastroenterology guideline suggests fibre supplements for chronic constipation, on low-certainty evidence.

Do probiotics work?

Some strains help with specific problems, such as reducing diarrhoea linked to antibiotics. Results don't carry over from one strain to another, and no probiotic has an authorised health claim.

Do lactase tablets work?

Yes, for lactose intolerance: the UK and EU registers authorise the claim that lactase improves lactose digestion in people who have difficulty digesting it, at 4,500 FCC units with each lactose-containing meal.

Which supplements have an approved claim for normal bowel function?

Very few. Chicory inulin may claim to contribute to normal bowel function by increasing stool frequency, at 12 g a day. Wheat bran, rye, oat and barley fibre have bowel claims in foods high in fibre, and lactulose (10 g in one serving) may claim faster intestinal transit. Psyllium and probiotics have no authorised claim.

Sources

Information only, not medical advice. No product on this page is a paid placement.