Cart

Your cart is empty

Macronutrient

Dietary fiber

Gut health and regularity, cholesterol and blood-sugar control, satiety

Essential nutrient

Reference intakes (RDA or AI) are set by the National Academies of Sciences, Engineering, and Medicine. Deficiency thresholds come from clinical and WHO guidance.

At a glance

Women, 19-50

25 g (14 g per 1,000 kcal) (21 g at 51+)

Men, 19-50

38 g (14 g per 1,000 kcal) (30 g at 51+)

Upper limit (adults)

Not established

How common is deficiency?

VERY COMMON - most adults eat well below the AI

Food sources

Animal sources

None (animal foods contain no fiber)

Plant sources

Beans, lentils, chia, flax, oats, whole grains, raspberries, pears, apples with skin, broccoli, artichokes, almonds

Deficiency and testing

Signs of deficiency

Constipation, hard stools, hemorrhoids, higher LDL cholesterol, blood sugar spikes, low satiety

Who is at higher risk

Low-plant diets, ultra-processed diets, older adults

How it is tested

No lab test; dietary assessment (food diary, 24-h recall); stool frequency/Bristol chart

Symptoms are not specific. Only a clinician with the right tests can tell whether you are deficient.

Supplement forms

Common forms

psyllium husk, methylcellulose, inulin/FOS, wheat dextrin, partially hydrolyzed guar gum, beta-glucan (oat/barley), fiber gummies/chews.

More effective

psyllium (best evidence for stool regularity, LDL cholesterol, and blood sugar); beta-glucan for cholesterol; wheat dextrin and partially hydrolyzed guar gum are gentler on the gut; whole foods remain best. Increase slowly and drink plenty of water.

Less effective

inulin/FOS at high doses (gas and bloating); fiber gummies (usually only 2-5 g, often with added sugar); insoluble bran for IBS (can worsen symptoms); taking fiber without enough water (constipation or blockage risk).

Safety, interactions and halal notes

Safety and interactions

Upper limit for adults: Not established. Going above the upper limit over time can cause harm, so check labels and talk to a clinician before high-dose supplements.

Halal note

The nutrient itself is not a halal question. For supplements, check the delivery form: gelatin (pork or non-halal bovine), capsule shells, glycerin, and alcohol-based carriers need halal certification. Ask for the halal certificate, not just a label claim. This is general guidance, not a certification.

Frequently asked questions

How much Dietary fiber do adults need per day?

Women 19-50: 25 g (14 g per 1,000 kcal) (21 g at 51+). Men 19-50: 38 g (14 g per 1,000 kcal) (30 g at 51+). Upper limit: Not established. Needs change with age, pregnancy and health conditions.

What are the signs of Dietary fiber deficiency?

Constipation, hard stools, hemorrhoids, higher LDL cholesterol, blood sugar spikes, low satiety. These signs are not specific, so only a clinician with the right tests can confirm a deficiency.

What are the best food sources of Dietary fiber?

Animal sources: None (animal foods contain no fiber). Plant sources: Beans, lentils, chia, flax, oats, whole grains, raspberries, pears, apples with skin, broccoli, artichokes, almonds.

Which form of Dietary fiber supplement is best?

Sources

← Back to the full nutrient guide

This page is for education only and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Supplements are not intended to diagnose, treat, cure or prevent any disease. Talk to a qualified clinician before starting a supplement, especially if you are pregnant, breastfeeding, take medicine or have a medical condition. Daily needs are US reference intakes for adults 19-50.

Share this page