What is the recommended daily fiber intake for adults?

Recommended Daily Fiber Intake for Adults

The recommended daily fiber intake for adults is 25-32 g/day for women and 30-35 g/day for men, which corresponds to approximately 14 g of fiber per 1,000 calories consumed. 1, 2

General Recommendations

• Adults should consume approximately 3-4 g of fiber per MJ (megajoule) of energy intake, which translates to the recommended 25-35 g/day for most adults 2
• The European Food Safety Authority (EFSA) recommends a minimum of 25 g/day of fiber for normal laxation in adults 2
• Higher intakes (more than 25 g/day) are necessary to reduce risk of coronary heart disease, type 2 diabetes, and improve weight maintenance 2
• Despite these recommendations, most adults in European countries and the USA do not meet the recommended fiber intake levels 2

Age-Specific Considerations

• For older adults, recommendations are somewhat lower at around 20 g/day for both men and women 2
• Older adults may need more fiber to compensate for impaired gastrointestinal function with age 2
• For children, recommendations are generally based on age and energy intake, with approximately 2 g/MJ being adequate 2

Health Benefits of Adequate Fiber Intake

• Populations that consume more dietary fiber have lower rates of chronic disease 3, 4
• Adequate fiber intake contributes to:
  • Normal bowel function and laxation 2
  • Reduced risk of cardiovascular disease 1, 5
  • Better glycemic control and improved insulin sensitivity 5
  • Weight management and enhanced weight loss in obese individuals 5
  • Reduced risk of certain gastrointestinal disorders 5

Types of Fiber and Their Benefits

• No specific recommendations exist for intake of particular fiber types, but certain fibers have demonstrated health benefits 2:
  • β-glucans from oats and barley (3 g/day) for cholesterol-lowering effects 1
  • Wheat fiber/arabinoxylan (10 g/day) for digestive health 2
  • Pectin (6 g/day) for various health benefits 1
  • Resistant starch replacing 14% of total starch for improved gut health 2

Practical Recommendations for Increasing Fiber Intake

• Choose high-fiber versions of carbohydrate foods such as:
  • Whole grain breads, cereals, pasta, and rice 2, 1
  • Vegetables, salads, and fruits 2, 1
  • Legumes, nuts, and seeds 1
• A fiber intake of 25 g/day would be adequate for normal laxation in adults, while more is needed for disease prevention 2
• For enteral nutrition, fiber-containing products should be used to contribute to normal bowel function 2

Common Pitfalls and Caveats

• Most people consume far less than the recommended amount of fiber (average intake in the US is only about 15-17 g/day) 3, 4
• Fiber recommendations based on energy intake may not be appropriate for all individuals, particularly older adults who consume less energy but may need more fiber 2
• Rapid increases in fiber intake can cause gastrointestinal discomfort; gradual increases are recommended 5
• Adequate hydration is essential when increasing fiber intake to prevent constipation 5
• While fiber supplements exist, consuming fiber through whole foods is generally preferred for obtaining associated nutrients and phytochemicals 3

By focusing on incorporating a variety of fiber-rich plant foods into the daily diet, most adults can achieve the recommended fiber intake levels and gain the associated health benefits.