Nutrition Expert: Saba Shaikh, Practicing Clinical Nutritionist, Mumbai.
Dietary fiber also known as roughage or bulk includes the parts of plant foods your body can’t digest or absorb. Unlike other food components, such as fats, proteins or carbohydrates — which your body breaks down and absorbs — fiber isn’t digested by your body. Instead, it passes relatively intact through your stomach, small intestine and colon and out of your body. (1)
Research regarding the potential health benefits of fiber has received considerable attention in the last several decades.
The Food and Drug Administration (FDA) in 2010 has approved two health claims for dietary fiber.
The first FDA claim states that, along with a decreased consumption of fats (<30% of calories), an increased consumption of dietary fiber from fruits; vegetables and whole grains may reduce some types of cancer. “Increased consumption” is defined as six or more one ounce equivalents, with three ounces derived from whole grains. Recent studies support this inverse relationship between dietary fiber and the development of several types of cancers including colorectal, small intestine, oral, larynx and breast
The second FDA claim supporting health benefits of DF states that diets low in saturated fat (<10% of calories) and cholesterol and high in fruits, vegetables and whole grain, have a decreased risk of leading to coronary heart disease (CHD). For most, an increased consumption of dietary fiber is considered to be approximately 25 to 35 g/d, of which 6 g are soluble fiber. Many studies support the inverse relationship of dietary fiber and the risk for CHD. For every 10 g of additional fiber added to a diet the mortality risk of CHD decreased by 17–35%. Risk factors for CHD include hypercholesterolemia, hypertension, obesity and type2 diabetes. (2)
Resistant Starch is a carbohydrate that resists digestion in the small intestine and ferments in the large intestine. As the fibers ferment slowly, they act as a prebiotic and feed the good bacteria in the gut hence cause less gas than other fibers. There are several types of resistant starch. When starches are digested they typically break down into glucose as it’s not digested in the small intestine it improves glycaemic control.
Other benefits of resistant starch include increased feeling of fullness, treatment and prevention of constipation, decrease in cholesterol, and lower risk of colon cancer. (3)
Types Of Fiber:
Insoluble Fiber is indigestible carbohydrate that does not dissolve in warm water and adds bulk to our stools helping to pass solids out more easily. The insoluble fiber found in our diet include cellulose, hemicellulose and lignins which is important for maintaining good gut health. Good sources of this form of fiber are vegetables, fruit and whole grains. (4)
Soluble Fiber dissolves in water forming viscous gels. They bypass the digestion of the small intestine and are easily fermented by the micro flora of the large intestine. They consist of pectin, gums, inulin-type fructans and some hemicelluloses.( Found in vegetables, fruits, and oat cereals.)
Most fiber containing foods include approximately one-third soluble and two-third insoluble fiber. (5)
Role of fiber in overall health
A high-fiber diet:
Normalizes bowel movements. Dietary fiber increases the weight and size of your stool and softens it. A bulky stool is easier to pass, decreasing your chance of constipation. If you have loose, watery stools, fiber may help to solidify the stool because it absorbs water and adds bulk to stool.
Helps maintain bowel health. A high-fiber diet may lower your risk of developing haemorrhoids and small pouches in your colon (diverticular disease). Studies have also found that a high-fiber diet likely lowers the risk of colorectal cancer. Some fiber is fermented in the colon. Researchers are looking at how this may play a role in preventing diseases of the colon.
Lowers cholesterol levels. Soluble fiber found in beans, oats, flaxseed and oat bran may help lower total blood cholesterol levels by lowering low-density lipoprotein, or “bad,” cholesterol levels. Studies also have shown that high-fiber foods may have other heart-health benefits, such as reducing blood pressure and inflammation.
Helps control blood sugar levels. In people with diabetes, fiber — particularly soluble fiber — can slow the absorption of sugar and help improve blood sugar levels. A healthy diet that includes insoluble fiber may also reduce the risk of developing type 2 diabetes.
Aids in achieving healthy weight. High-fiber foods tend to be more filling than low-fiber foods, so you’re likely to eat less and stay satisfied longer. And high-fiber foods tend to take longer to eat and to be less “energy dense,” which means they have fewer calories for the same volume of food.
Helps you live longer. Studies suggest that increasing your dietary fiber intake — especially cereal fiber — is associated with a reduced risk of dying from cardiovascular disease and all cancers. (6)
Add fiber to your diet by making small, gradual changes can add up to a big difference in the nutritional value of your diet. Experiment with fresh foods and don’t be afraid to try new foods and recipes. Here are a few practical tips for adding fiber to your diet.
Cook in microwave to save time and nutrients
Cook only until tender-crisp to retain taste and nutrients
Beans, peas and other legumes
Replace the meat in salads and main dishes with pre-soaked dried beans and peas
Pre-soaking reduces the gas-producing potential of beans if you discard the soaking water and cook using fresh water
Use a slow cooker for bean soups and stews
Snack on fruit anytime, anywhere
Experiment with unusual fruits such as kiwi, pineapple, and mangos
Leave peelings on fruit whenever possible
Use fresh and dried fruit in muffins, pancakes, quick breads, and on top of frozen yogurt
Whole grain products
Choose whole-grain varieties of breads, muffins, bagels, and English muffins
Try fresh pasta instead of dried
Mix barely cooked vegetables with pasta for a quick pasta salad. (7)
It is suggested that healthy adults should eat between 20 and 35 g of dietary fiber each day. (8)
Hazards of excess fiber intake
Loose stools or diarrhoea
Intestinal blockage in people with Crohn’s disease.
Reduced blood sugar levels, which is important to know if you have diabetes
Temporary weight gain
Call your doctor right away if you’re experiencing nausea, vomiting, a high fever, or a complete inability to pass gas or stool. (9)
How to relieve symptoms of too much fiber?
Drink plenty of water.
Stop using any fiber supplements.
Avoid high-fiber foods.
Eat a bland diet.
Remove fiber-fortified foods from your diet.
Look for foods that contain substances such as inulin and chicory root extract.
Engage in light physical activities, like walking, as often as possible.
Consider keeping an online diary of your food intake to help you see how much fiber you’re getting each day.
Consider following a low FODMAP diet if you have irritable bowel syndrome (IBS). This temporary diet can improve symptoms by removing fermentable, fibrous foods from your diet.
Once you start feeling better, you should slowly re-introduce fiber-rich foods into your diet. Instead of eating fiber-rich foods in one meal, spread them out throughout the day. (10)