Fibers are the structural parts of plants and are found in all plant-derived foods — vegetables, fruits, whole grains, and legumes. Most dietary fibers are polysaccharides. Dietary fibers pass through the body undigested and contribute no monosaccharides, and therefore little or no energy (less then 2 calories).
Fiber has been long associated with its effect on helping constipation, but increasing evidence now supports the role of fiber in the prevention and treatment of many chronic diseases. Higher fiber intakes have been linked with a decreased risk of cardiovascular disease, type 2 diabetes, and even some forms of cancer, such as colon cancer.
Fiber may also play a role in lowering blood pressure, and in preventing obesity by limiting weight gain. In addition, higher fiber diets may provide some benefit for inflammatory bowel disease or irritable bowel syndrome.
Dietary fibers are split into two groups according to their solubility.
Some dietary fibers dissolve in water (soluble fibers), form gels (viscous), and are easily digested by bacteria in the colon (fermentable).
These are mostly found in oats, barley, legumes, and citrus fruits, and are most often associated with protecting against heart disease and diabetes by lowering blood cholesterol and glucose levels.
The second group do not dissolve in water (insoluble fibers), do not form gels (non-viscous), and are less readily fermented. They’re found mostly in whole grains (bran) and vegetables, they promote bowel movements and help avoid constipation.
A few starches are classified as dietary fibers. Known as resistant starches, they escape digestion and absorption in the small intestine.
Starch may resist digestion for several reasons, including the body’s efficiency in digesting starches and the food’s physical properties. Resistant starch is common in whole or partially milled grains, legumes, and just-ripened bananas.
Cooked potatoes, pasta, and rice that have been chilled also contain resistant starch. Similar to insoluble fibers, resistant starch may support a healthy colon.
Daily fiber intake should be at least 25 grams per day for women and about 38 grams for men. However average individual daily dietary fiber intake about 15 grams a day.
A high-fiber diet may be a little challenging when you first start, because it can increase intestinal gas, so you should add the fiber in gradually, as tolerated.
Keep adding high fiber foods in your diet, and you will see overall improvement in your health.
Some examples of good fiber sources include:
• Flaxseed: 10 grams (2.8 grams fiber)
• Chia seed: 28 grams (10.6 grams of fiber)
• Quinoa: 185 grams cooked (5.2 grams of fiber)
• Lentils: 198 grams (15.6 grams of fiber)
• Broccoli: 1 cup (5 grams of fiber)
• Split peas: 1 cup cooked (16 grams of fiber)
• Peas: 160 grams (8.8 grams of fiber)
• Fig: One large (1.9 grams of fiber)
• Coconut: 80 grams (7.2 grams of fiber)
• Avocado: 150 grams (10.1 grams of fiber)
• Asian Pear: 275 grams (9.9 grams of fiber)
• Collard green: 1 cup cooked (8 grams of fiber)
• Raspberry: 123 grams (8 grams of fiber)
Ayda Ersoy is a nutrition and fitness director at The Diet Doc Hawaii. She can be reached at DietDocHawaii.com, Ayda@DietDocHawaii.com or (808) 276-6892