How Much Fibre Do Children Need? UK Amounts by Age

UK children need about 15 g of fibre a day from age 2 to 5, 20 g from 5 to 11, 25 g from 11 to 16 and the adult 30 g from 16, figures set by the Scientific Advisory Committee on Nutrition in 2015 and used by the NHS; there is no target under 2, and the NHS says not to give under-2s only wholegrain starchy foods, because they fill a small child up before they have taken in the energy and nutrients they need.^{1, 2, 3} Most children fall short: in the 2019 to 2023 national survey, 4 to 10-year-olds averaged 14.5 g a day and 11 to 18-year-olds 15.4 g, with 14% and 4% reaching their targets.⁴ No fibre supplement is the next step for a child, and a constipated child is a GP or health-visitor conversation. The Wellgard fibre guide has the adult figures and the whole by-age table.

How much fibre do children need by age?

SACN scaled the children's figures from the adult 30 g by energy need and rounded them to the nearest 5 g; the NHS uses the same bands.^{1, 2} Averages and the share reaching the target are from the 2019 to 2023 survey.⁴

Among children, the teenage gap is the largest, about 10 g a day, and girls eat less than boys at every age.⁴

Where do the children's figures come from, and what about "age plus 5"?

SACN derived the children's values from the adult 30 g, which it set in 2015 on the cohort evidence for heart disease, type 2 diabetes and bowel cancer. There is little trial evidence in children and little data on whether very high intakes affect growth, so the bands are an extrapolation rather than measurements in children; a 2012 review reached the same conclusion.^{1, 5} The "age plus 5" rule in many online answers, by which a six-year-old "needs 11 g", is a 1995 American proposal, not UK guidance, and it gave age plus 5 g as a minimum with age plus 10 g as the upper end of a safe range. The minimum falls short of the UK bands at every age, and the upper end only reaches 20 g at about age 10.⁶

What does 20 g of fibre look like for a six-year-old?

A day of ordinary child-sized portions reaches 20 g without anything unusual. Gram values are approximate, from the UK food composition tables; which foods are high in fibre has the full table.⁷

• Breakfast: two biscuits of a wholewheat breakfast cereal with milk, about 4 g, and half a banana, about 1 g.
• Lunch: a sandwich on two slices of wholemeal bread, about 5 g, carrot and cucumber sticks, about 1 g, and a satsuma, about 1 g.
• Snack: an apple with the skin on, about 2 g, or two oatcakes, about 1½ g.
• Dinner: a small jacket potato with its skin, about 3 g, 50 g of baked beans, about 2 g, and a spoon of peas or sweetcorn, about 2 g.

That is about 21 g. For a 2 to 5-year-old, smaller portions of the same foods land near 15 g.

How can I add fibre to my child's diet?

Gradually, from food, with drinks alongside. The NHS list for children is fruit, vegetables and starchy foods, choosing wholegrain versions and potatoes with skins on where the child will eat them.²

• Keep the fruit and vegetables they already eat and add one more portion a day; berries, pears, kiwis, peas and sweetcorn are high for their size.
• From age 2, swap one white starchy food at a time for a wholegrain version. Under 2, mix white and wholegrain.³
• Add pulses in forms children accept: baked beans, hummus, lentils in a sauce, chickpeas in a curry.
• Offer water with meals and snacks; fibre needs fluid to keep stools soft. The NHS says babies under 12 months do not need fruit juice or smoothies, and for older children advises diluted juice with meals only.⁸
• Build up over two to four weeks.

"High-fibre drinks for kids" are not needed: water with a piece of fruit does the same job.

What are the signs a child is short of fibre?

There is no blood test for fibre, so the signs are in the nappy or the toilet. The NHS describes constipation in children as fewer than three poos in the last week; large, hard poos, or poos like rabbit droppings or little pellets; straining or pain when pooing; bleeding during or after; and poor appetite or a tummy ache that eases after a poo. In children over 1, soiled pants can be constipation too: runny poo leaking around a hard mass, which the NHS calls overflow soiling and which is not the child's fault.⁹

Do children need fibre supplements or fibre drinks?

No. The UK targets rest on fibre-rich foods, and the fibre, prune and gut supplements sold for adults, Wellgard's included, are adult products whose labels say to keep them out of the reach of children. The GB claims register attaches its own warning to glucomannan, pectin and cellulose fibres: "Warning of choking to be given for people with swallowing difficulties or when ingesting with inadequate fluid intake".¹⁰

The trial evidence in children is thin. In 80 children aged 3 to 16 with functional constipation, 2.5 g a day of glucomannan for four weeks was no better than placebo, with more tummy pain in the first and last weeks.¹¹ In 103 children with irritable bowel syndrome, mean age 13, six weeks of psyllium reduced pain episodes by 8.2 against 4.1 on placebo, with no difference in pain intensity; any fibre for a child with a diagnosed bowel condition is the paediatric team's decision.¹²

What should you do if your child is constipated?

Take them to a GP early. The NHS says the longer a child is constipated the harder it is to resolve, that laxatives are often recommended for children eating solid foods alongside changes to diet and lifestyle, that treatment can take several months, and that a GP may advise continuing the laxative for a while after the constipation clears to keep poo soft.⁹ The fear that laxatives make a child's bowel "lazy" delays treatment: a child who withholds because pooing has hurt needs soft stools for long enough to forget the pain, which is a GP's prescription, not a diet.

Alongside that, the NHS steps for parents: plenty of fluids (extra breastfeeds for a breastfed baby, extra water between feeds for a formula-fed one, cooled boiled water under 6 months, and water with meals for an older child); plenty of fruit and vegetables; sitting on the potty or toilet regularly, such as after meals, with feet flat on the floor or a step; keeping active; and keeping things relaxed.⁹ See a GP sooner if there is blood in the poo, vomiting, a swollen tummy, weight loss or poor growth, or if a baby under a year is constipated.

Which home remedies should you avoid?

Three remedies passed around parenting forums are unsafe or unhelpful. Brown sugar in cooled boiled water is not an NHS remedy at any age: babies do not need sugar added to anything, and sugar water does not treat constipation. Orange juice, prune juice or watered-down juice for a baby under 12 months is the second: the NHS says babies that age do not need fruit juice or smoothies, and a constipated baby needs a GP or health visitor.^{8, 9} Bran stirred into a toddler's food is the third: bran is not advised for toddlers, the NHS says under-2s should not have only wholegrain starchy foods, and a toddler's fibre is better from fruit, vegetables and pulses.³

Frequently asked questions

Is bran or high-fibre cereal OK for a one- or two-year-old?

A spoon of a wholegrain cereal is fine in a mixed diet, but the NHS says not to give under-2s only wholegrain starchy foods; after 2, add wholegrains gradually.³ Pure bran is not a food for a toddler.

What is a natural laxative for a child?

Fluid, fruit, vegetables and a daily toilet routine, which is the NHS list.⁹ If those have not worked within a week or two, the NHS route is a GP, and the laxatives a GP prescribes are the treatment for a child who withholds.

Can I give prune juice to a baby?

The NHS says babies under 12 months do not need fruit juice or smoothies, and a constipated baby should be seen by a GP or health visitor.^{8, 9}

What are the guidelines for a balanced diet for children?

The NHS says the Eatwell Guide does not apply under 2; after 2, children move towards the family's foods in its proportions, and by 5 they can eat a healthy balanced diet like the one recommended for adults. Young children, especially under 2, need the energy that fat provides.^{3, 13}

What should a 70-year-old be eating for fibre?

The adult 30 g a day does not fall with age; adults aged 65 to 74 averaged 16.9 g in the 2019 to 2023 survey.⁴ For adults of any age, our constipation guide sets out the NHS steps.

Sources

1. Scientific Advisory Committee on Nutrition. Carbohydrates and Health, 2015. gov.uk.
2. NHS. How to get more fibre into your diet. nhs.uk.
3. NHS. What to feed young children. nhs.uk.
4. National Diet and Nutrition Survey 2019 to 2023. gov.uk.
5. Kranz S, et al. What do we know about dietary fiber intake in children and health? Advances in Nutrition, 2012. PubMed 22332100.
6. Williams CL, et al. A new recommendation for dietary fiber in childhood. Pediatrics, 1995. PubMed 7494677.
7. Public Health England. McCance and Widdowson's Composition of Foods Integrated Dataset (CoFID), 2021. gov.uk. Portion values are approximate.
8. NHS. Drinks and cups for babies and young children. nhs.uk.
9. NHS. Constipation in children. nhs.uk.
10. Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register. gov.uk.
11. Chmielewska A, et al. Glucomannan is not effective for the treatment of functional constipation in children. Clinical Nutrition, 2011. PubMed 21320737.
12. Shulman RJ, et al. Psyllium fiber reduces abdominal pain in children with irritable bowel syndrome. Clinical Gastroenterology and Hepatology, 2017. PubMed 27080737.
13. NHS. The Eatwell Guide. nhs.uk.