Author: Betty Kovacs, MS, RD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

• A little fiber history
• What is fiber?
• Fiber for weight control
• Fiber for controlling diabetes
• Fiber for preventing heart disease
• Fiber for bowel disorders
• Fiber for preventing or treating constipation
• Recommendations for fiber intake
• Some helpful hints about fiber

Fiber and Increased Gas

Medical Author: Jay W. Marks, MD

When I've tried to put extra fiber in my diet, my gas level gets even worse. Is there a product that will help increase fiber but not increase gas?

Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation though it also may have additional uses such as the treatment of diverticular disease of the colon. Many types of fiber bind to water and keep the water within the intestine. The fiber and water adds bulk (volume) to the stool, and the water softens the stool. Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because bacteria within the colon, unlike the intestine of humans, are capable of digesting fiber to a small extent. The bacteria produce gas as a by-product of their digestion of fiber.

There are different sources of fiber, and the type of fiber varies from source to source. Some types of fiber are digested to a greater extent by colonic bacteria than other types of fiber. The better-digested fiber produces more gas.

All fibers, no matter their source, can cause flatulence; however, since bacteria vary in their ability to digest different types of fiber, different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This makes the selection of the best type of fiber for each individual (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. The choice becomes a matter of trial and error.

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Top Searched Fiber Terms

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A little fiber history

Fiber became a household word back in 1970s when Dr. Denis Burkitt, a man nicknamed the Fiber Man, and his colleagues made "the fiber hypothesis" that states that fiber can prevent certain diseases. Through their work in Africa, they discovered that diseases that were common in the Western cultures were not common there. These included heart attacks and high blood pressure (cardiovascular diseases), obesity and diabetes (metabolic disorders), intestinal problems ( constipation, diverticulosis, diverticulitis, gallstones, appendicitis, hemorrhoids, polyps, and colon cancer), varicose veins and blood clots ( deep vein thrombosis). The primary dietary difference was the high intake of fiber and low intake of refined carbohydrates in the African population. Burkitt also noted the emergence of these diseases in the United States and England after 1890 following the introduction of a new milling technique that removed fiber from whole grain flour to produce white flour.

While the exact mechanism by which fiber might prevent these diseases remained unknown, Burkitt made a discovery about the beneficial impact that fiber had on bowel movements and how that related to certain diseases. Burkitt noted that he was able to predict the number of a patient's hospital visits from the size and frequency of their bowel movements. Those with high intakes of fiber had more frequent and bulky stools and had less illness. Burkitt proposed that fiber's health benefits stemmed from its ability to increase stool bulk and speed up how quickly stool moves through the colon. Since these findings, controversy remains. A great deal of research has both supported and disputed what Burkitt had discovered.

Next: What is fiber?

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• Fiber Index
• Glossary

GENERIC NAME: insulin

BRAND NAME: various

DRUG CLASS AND MECHANISM: Insulin is a naturally-occurring hormone secreted by the pancreas. Insulin is required by the cells of the body in order for them to remove and use glucose from the blood. From glucose the cells produce the energy that they need to carry out their functions. Researchers first gave an active extract of the pancreas containing insulin to a young diabetic patient in 1922, and the FDA first approved insulin in 1939. Currently, insulin used for treatment is derived from beef and pork pancreas as well as recombinant (human) technology. The first recombinant human insulin was approved by the FDA in 1982.

Patients with diabetes mellitus have an inability to take up and use glucose from the blood, and, as a result, the glucose level in the blood rises. In type 1 diabetes, the pancreas cannot produce enough insulin. Therefore, insulin therapy is needed. In type 2 diabetes, patients produce insulin, but cells throughout the body do not respond normally to the insulin. Nevertheless, insulin also may be used in type 2 diabetes to overcome the resistance of the cells to insulin. By increasing the uptake of glucose by cells and reducing the concentration of glucose in the blood, insulin prevents or reduces the long-term complications of diabetes, including damage to the blood vessels, eyes, kidneys, and nerves. Insulin is administered by injection under the skin (subcutaneously). The subcutaneous tissue of the abdomen is preferred because absorption of the insulin is more consistent from this location than subcutaneous tissues in other locations.

Regular (rapid onset of action, short duration of action) and NPH (slower onset of action, longer duration of action) human insulin are the most commonly-used preparations. Regular insulin has an onset of action (begins to reduce blood sugar) within 30 minutes of injection, reaches a peak effect at 1-3 hours, and has effects that last 6-8 hours.

NPH insulin is an insulin with an intermediate duration of action. It has an onset of action starting about 2 hours following injection. It has a peak effect 4-12 hours after injection, and a duration of action of 18-26 hours.

Lente insulin also is an insulin with an intermediate duration of action. It has an onset of action 2-4 hours after injection, a peak activity 6-12 hours after injection, and a duration of action of 18 to 26 hours. Ultralente insulin is a long-acting insulin with an onset of action 4-8 hours after injection, a peak effect 10-30 hours after injection, and a duration of action of more than 36 hours.

An ultra rapid-acting insulin, insulin lispro is a chemically-modified, natural insulin. It was approved by the FDA in June, 1996. As compared to regular insulin, insulin lispro has a more rapid onset of action, an earlier peak effect, and a shorter duration of action. It reaches peak activity 0.5-2.5 hours after injection. Therefore, insulin lispro should be injected 15 minutes before a meal as compared to regular insulin which is injected 30-60 minutes before a meal.

Insulin aspart and insulin glargine are both human insulin that have had their chemical composition slightly altered. The chemical changes provide insulin aspart with a faster onset of action (20 minutes) and a shorter duration of action (3-5 hours) than regular human insulin. It reaches peak activity 1-3 hours after injection. Insulin glargine has a slower onset of action (70 minutes) and a longer duration of action (24 hours) than regular human insulin. Its activity does not peak.

GENERIC: no

PRESCRIPTION: yes

PREPARATIONS: Insulin comes in three different forms-vials, prefilled syringes, and cartridges. The cartridges are to be used in a pen-like device that simplifies injection. Human recombinant insulin, insulin lispro, insulin aspart, and insulin glargine are the commonly-used insulins. Beef and pork insulin are infrequently used. Regular human insulin (Novolin R, Humulin R) is available in vials, cartridges, and prefilled syringes.

NPH human insulin (Novolin N, Humulin N) is available in vials, cartridges and prefilled syringes. A mixture of 70% NPH human insulin and 30% regular human insulin (Novolin 70/30, Humulin 70/30) is available in vials, cartridges and pre-filled syringes.

• 1
• 2
• 3
• Next

• insulin Index
• Glossary

GENERIC NAME: insulin

BRAND NAME: various

DRUG CLASS AND MECHANISM: Insulin is a naturally-occurring hormone secreted by the pancreas. Insulin is required by the cells of the body in order for them to remove and use glucose from the blood. From glucose the cells produce the energy that they need to carry out their functions. Researchers first gave an active extract of the pancreas containing insulin to a young diabetic patient in 1922, and the FDA first approved insulin in 1939. Currently, insulin used for treatment is derived from beef and pork pancreas as well as recombinant (human) technology. The first recombinant human insulin was approved by the FDA in 1982.

Patients with diabetes mellitus have an inability to take up and use glucose from the blood, and, as a result, the glucose level in the blood rises. In type 1 diabetes, the pancreas cannot produce enough insulin. Therefore, insulin therapy is needed. In type 2 diabetes, patients produce insulin, but cells throughout the body do not respond normally to the insulin. Nevertheless, insulin also may be used in type 2 diabetes to overcome the resistance of the cells to insulin. By increasing the uptake of glucose by cells and reducing the concentration of glucose in the blood, insulin prevents or reduces the long-term complications of diabetes, including damage to the blood vessels, eyes, kidneys, and nerves. Insulin is administered by injection under the skin (subcutaneously). The subcutaneous tissue of the abdomen is preferred because absorption of the insulin is more consistent from this location than subcutaneous tissues in other locations.

Regular (rapid onset of action, short duration of action) and NPH (slower onset of action, longer duration of action) human insulin are the most commonly-used preparations. Regular insulin has an onset of action (begins to reduce blood sugar) within 30 minutes of injection, reaches a peak effect at 1-3 hours, and has effects that last 6-8 hours.

NPH insulin is an insulin with an intermediate duration of action. It has an onset of action starting about 2 hours following injection. It has a peak effect 4-12 hours after injection, and a duration of action of 18-26 hours.

Lente insulin also is an insulin with an intermediate duration of action. It has an onset of action 2-4 hours after injection, a peak activity 6-12 hours after injection, and a duration of action of 18 to 26 hours. Ultralente insulin is a long-acting insulin with an onset of action 4-8 hours after injection, a peak effect 10-30 hours after injection, and a duration of action of more than 36 hours.

An ultra rapid-acting insulin, insulin lispro is a chemically-modified, natural insulin. It was approved by the FDA in June, 1996. As compared to regular insulin, insulin lispro has a more rapid onset of action, an earlier peak effect, and a shorter duration of action. It reaches peak activity 0.5-2.5 hours after injection. Therefore, insulin lispro should be injected 15 minutes before a meal as compared to regular insulin which is injected 30-60 minutes before a meal.

Insulin aspart and insulin glargine are both human insulin that have had their chemical composition slightly altered. The chemical changes provide insulin aspart with a faster onset of action (20 minutes) and a shorter duration of action (3-5 hours) than regular human insulin. It reaches peak activity 1-3 hours after injection. Insulin glargine has a slower onset of action (70 minutes) and a longer duration of action (24 hours) than regular human insulin. Its activity does not peak.

GENERIC: no

PRESCRIPTION: yes

PREPARATIONS: Insulin comes in three different forms-vials, prefilled syringes, and cartridges. The cartridges are to be used in a pen-like device that simplifies injection. Human recombinant insulin, insulin lispro, insulin aspart, and insulin glargine are the commonly-used insulins. Beef and pork insulin are infrequently used. Regular human insulin (Novolin R, Humulin R) is available in vials, cartridges, and prefilled syringes.

NPH human insulin (Novolin N, Humulin N) is available in vials, cartridges and prefilled syringes. A mixture of 70% NPH human insulin and 30% regular human insulin (Novolin 70/30, Humulin 70/30) is available in vials, cartridges and pre-filled syringes.

• 1
• 2
• 3
• Next

• insulin Index
• Glossary