Skip to main content

Dietary Fiber

Macronutrient Unit: g

Indigestible carbohydrate that promotes digestive health, helps regulate blood sugar, and supports healthy cholesterol levels.

Recommended Daily Allowance (RDA)

38.0
Adult Male
g/day
25.0
Adult Female
g/day
Daily Requirements by Life Stage 16 groups
Life StageRDA / AI (g/day)Upper Limit (g/day)
Children 1-3 years19.0 *
Children 4-8 years25.0 *
Males 9-13 years31.0 *
Females 9-13 years26.0 *
Males 14-18 years38.0 *
Females 14-18 years26.0 *
Males 19-30 years38.0 *
Females 19-30 years25.0 *
Males 31-50 years38.0 *
Females 31-50 years25.0 *
Males 51-70 years30.0 *
Females 51-70 years21.0 *
Males 70+ years30.0 *
Females 70+ years21.0 *
Pregnancy28.0 *
Lactation29.0 *

* = Adequate Intake (AI) where no RDA established

Top Foods Highest in Dietary Fiber

Amount per 100g serving. Values in g per 100g.

Foods Highest in Dietary Fiber (Table)

#FoodPer 100gGroup
1Corn bran, crude79.0 gCereal Grains and Pasta
2Gums, seed gums (includes locust bean, guar)77.3 gSweets
3Fungi, Cloud ears, dried70.1 gVegetables and Vegetable Products
4Spices, curry powder53.2 gSpices and Herbs
5Spices, cinnamon, ground53.1 gSpices and Herbs
6Spices, savory, ground45.7 gSpices and Herbs
7Baobab powder44.5 gFruits and Fruit Juices
8Pinon Nuts, roasted (Navajo)43.4 gAmerican Indian/Alaska Native Foods
9Wheat bran, crude42.8 gCereal Grains and Pasta
10Spices, rosemary, dried42.6 gSpices and Herbs
11Spices, oregano, dried42.5 gSpices and Herbs
12Spices, coriander seed41.9 gSpices and Herbs
13Cereals ready-to-eat, SUN COUNTRY, KRETSCHMER Toasted Wheat 41.3 gBreakfast Cereals
14Spices, sage, ground40.3 gSpices and Herbs
15Spices, marjoram, dried40.3 gSpices and Herbs
16Spices, fennel seed39.8 gSpices and Herbs
17Carob flour39.8 gLegumes and Legume Products
18Spices, caraway seed38.0 gSpices and Herbs
19Spices, basil, dried37.7 gSpices and Herbs
20Spices, thyme, dried37.0 gSpices and Herbs

Health Effects of Dietary Fiber

Function

Dietary fiber supports digestive health, promotes satiety, and feeds beneficial gut bacteria. Soluble fiber helps lower cholesterol and regulate blood sugar. Insoluble fiber prevents constipation.

Deficiency Signs

Low fiber intake is associated with constipation, diverticular disease, increased colorectal cancer risk, poor glycemic control, and elevated LDL cholesterol.

Excess / Toxicity

Very high fiber intake (>70g/day) may cause bloating, gas, and cramping. Can reduce absorption of minerals like iron, zinc, and calcium if phytate content is high.

Absorption & Interactions

How It’s Absorbed

Fiber is not digested by human enzymes. Soluble fiber is fermented by colonic bacteria producing short-chain fatty acids (butyrate, propionate, acetate). Insoluble fiber passes through largely intact.

Key Interactions
Iron Inhibitor
Phytate in high-fiber foods can reduce non-heme iron absorption by 50-65%
Zinc Inhibitor
High phytate:zinc ratios in whole grains can impair zinc bioavailability
Calcium Inhibitor
Oxalates and phytates in some high-fiber foods can bind calcium, reducing absorption

Estimated Dietary Fiber Adequacy by Country

Estimated from national food supply composition (FAO food balance sheets). Shows food supply availability relative to Estimated Average Requirement (EAR), not actual intake. Does not account for fortification, supplements, or distribution inequality.

180 countries12 below 50% EAR14 above 100% EARAvg: 71% EAR
% of EAR from food supply:0-25%25-50%50-75%75-100%100-150%>150%

Frequently Asked Questions

How much Dietary Fiber do I need per day?

Adult males need 38.0 g/day and adult females need 25.0 g/day.

Which food has the most Dietary Fiber?

The food highest in Dietary Fiber is Corn bran, crude with 79.0 g per 100g.

What does Dietary Fiber do in the body?

Indigestible carbohydrate that promotes digestive health, helps regulate blood sugar, and supports healthy cholesterol levels.