FDA's Definition of Dietary Fiber
In 2016, the FDA updated its definition of dietary fiber. This update aimed to clarify which non-digestible carbohydrates could be listed as dietary fiber on the Nutrition Facts label. The FDA now differentiates between intrinsic/intact fibers found naturally in plants and isolated or synthetic fibers added to foods.
Intrinsic and Intact Fibers
These are fibers that exist naturally within whole plant foods such as fruits, vegetables, whole grains, nuts, and legumes. The FDA considers the fiber in these foods to be beneficial without requiring specific testing.
Isolated and Synthetic Fibers
Fibers that are extracted from plants or created synthetically must have a demonstrated beneficial physiological effect on human health to be counted as dietary fiber on a food label. The FDA maintains a list of approved isolated and synthetic fibers that meet this criteria.
Good Sources of Naturally Occurring Fiber
Incorporating a variety of whole, unprocessed plant foods is key to increasing natural fiber intake.
- Legumes: Lentils, beans (black, navy, pinto), and split peas are excellent sources. A cup of cooked lentils provides 15.5 grams of fiber.
- Whole Grains: Look for whole-wheat products, oatmeal, brown rice, quinoa, and barley. Some bran cereals can offer up to 14 grams of fiber per serving.
- Fruits: High-fiber fruits include raspberries, blackberries, pears, and apples with their skin. Dried fruits like apricots and figs are also good options.
- Vegetables: Broccoli, Brussels sprouts, artichokes, sweet potatoes with skin, and green peas contribute significant fiber.
- Nuts and Seeds: Chia seeds, almonds, and sunflower kernels are convenient sources that can be added to various dishes.
FDA-Approved Added Fiber
The FDA has approved several isolated and synthetic fibers for use in food products, provided they have a proven health benefit. Examples include:
- Beta-glucan soluble fiber
- Psyllium husk
- Cellulose
- Guar gum
- Pectin
- Locust bean gum
- Inulin and inulin-type fructans
Natural vs. Added Fiber: A Comparison
To understand the key differences between natural and added fibers, consider the following table:
| Feature | Naturally Occurring (Intrinsic/Intact) Fiber | Added (Isolated/Synthetic) Fiber |
|---|---|---|
| Source | Whole plant foods (fruits, vegetables, grains, legumes) | Extracted from plants or created synthetically |
| Associated Nutrients | Comes with a complete package of vitamins, minerals, and antioxidants | Often lacks the full nutrient profile of whole foods |
| FDA Approval | Automatically meets the FDA's beneficial criteria | Requires a demonstration of physiological benefit to meet FDA definition |
| Benefits | Provides both soluble and insoluble fiber, supporting bowel health and cholesterol | Provides specific health benefits, such as cholesterol reduction or bowel regulation |
| Potential Effects | Generally well-tolerated when increased gradually | May cause gas and bloating in some individuals |
How to Increase Your Fiber Intake
Increasing fiber intake involves making simple dietary choices. Focus on adding more whole foods to your meals. The FDA suggests using the Nutrition Facts label to identify foods that are a 'good source' (10-19% of the Daily Value) or 'high' (20% or more) in fiber. The Daily Value for fiber is 28 grams per day for adults on a 2,000-calorie diet. Strategies include making half your grains whole grains and regularly incorporating beans and lentils. More detailed guidance is available on the FDA's website.
Conclusion
According to the FDA, a good source of fiber comes from two main categories: the intrinsic fiber found naturally in whole plant foods and specific isolated or synthetic fibers that have scientifically proven health benefits. Prioritizing whole foods like vegetables, fruits, whole grains, and legumes is generally the best approach for a comprehensive nutrient intake. When consuming packaged foods, checking the Nutrition Facts label helps ensure the fiber content aligns with FDA-approved sources and contributes to your daily goals, supporting overall health.
