1. Fiber Presented by Janice Hermann, PhD, RD/LD
OCES Adult and Older Adult Nutrition Specialist

2. Fiber
Fiber is the structural part of plants and is found in vegetables, fruits, grains and legumes.
Most dietary fibers are polysaccharides, like starch, but they are not digestible.
The human body lacks the enzymes needed to digest and absorb fiber.
As a result fibers reach the lower intestine intact where intestinal bacteria can ferment some fiber.
Fiber
Fibers are the structural part of plants and are found in all plant foods including vegetables, fruits, grains and legumes. Most dietary fibers are polysaccharides, as are starches, but they are not digested by the human body. Starch is a long chain of glucose molecules linked together with alpha bonds. Fiber is a long chain of glucose molecules linked together with beta bonds. The human body does not have the enzymes to break beta bonds therefore fiber is not digested and absorbed and does not provide calories. The undigested fiber passes into the lower intestine where intestinal bacteria can ferment (breakdown) some fibers.

3. Fiber
Fiber
Fibers are the structural part of plants and are found in all plant foods including vegetables, fruits, grains and legumes. Most dietary fibers are polysaccharides, as are starches, but they are not digested by the human body. Starch is a long chain of glucose molecules linked together with alpha bonds. Fiber is a long chain of glucose molecules linked together with beta bonds. The human body does not have the enzymes to break beta bonds therefore fiber is not digested and absorbed and does not provide calories. The undigested fiber passes into the lower intestine where intestinal bacteria can ferment (breakdown) some fibers.

4. Fiber Nonstarch polysaccharide fibers Nonpolysaccharide fiber
Cellulose
Hemicellulose
Pectin
Gums
Mucilages
Nonpolysaccharide fiber
Lignins
Cutins
Tannins
Resistant Starches
Fibers are often called nonstarch polysaccharids. Nonstarch polysaccharide fibers include cellulose, hemicellulose, pectin, gums and mucilages. Some nonpolysaccharide fibers exist including lignins, cutins and tannins.
Cellulose is found in all vegetables, fruits and legumes. Hemicellulose is found in cereal grains. Pectin is commonly found in vegetables and fruits. Gums are secreted from plants when the plant is cut. Mucilages are similar to gums and include psyllium and carrageenan. Lignin is found in woody vegetables such as carrots and the small seeds of fruits such as strawberries.
A few starches, called resistant starches, resist digestion and absorption and are classified as fibers. The physical property of the food or a persons efficiency in digestion can affect a starches resistance to digestion. Resistant starches are common in whole legumes, raw potatoes and unripe bananas.

5. Types of Fiber
There are many different types of fiber, in general fibers can be divided into two types based on their physical properties.
Soluble fibers
Insoluble fibers
Fibers can be divided into two general types based on their physical properties; soluble fibers and insoluble fibers.

6. Soluble Fibers
Soluble fibers dissolve in water, form gels and are easily digested by bacteria in the lower intestine.
Provides a feeling of fullness.
Slow down the rate food leaves the stomach.
May have a role with heart disease, diabetes and colon cancer
Found in legumes and fruits
Soluble Fibers
Soluble fibers dissolve in water, form gels, and are easily digested by bacteria in the lower intestine. This contributes to a feeling of fullness in the stomach. Soluble fibers usually slow down the rate food leaves the stomach. Soluble fibers are commonly found in legumes and fruits and have been associated with protecting against heart disease and diabetes by lowering blood cholesterol and blood glucose levels. Soluble fibers may also protect against colon cancer.

7. Insoluble Fiber
Insoluble fibers absorb water and swell up resulting in a larger softer stool that is easier and quicker to pass.
Provides a feeling of fullness
Helps with intestinal function
May help with colon cancer
Found in grains and vegetables
Insoluble Fiber
Insoluble fibers do not dissolve in water and do not form gels and are less readily fermented. Insoluble fibers are mostly found in grains and vegetables and help with intestinal function. These types of fibers absorb water and swell up in the intestine, thus providing a feeling of fullness and resulting in a larger softer stool that is easier and quicker to pass.

8. Fiber and Health Both fiber types are important for health.
Fibers are beneficial for many conditions; constipation, diarrhea, diverticular disease, heart disease, diabetes and colon cancer.
Fiber is only one factor involved in these conditions.
Health Benefits of Dietary Fibers
Both soluble and insoluble dietary fibers are important for good health. Dietary fibers provide health benefits for many conditions including constipation, diverticular disease, heart disease, diabetes and colon cancer.
However, dietary fibers are only one factor involved in these conditions.

9. Fiber and Health
Foods high fiber have many factors that may be factors in lowering disease risk.
High fiber
Low in fat
High vitamins (antioxidants)
High in minerals
High in phytochemicals
Fiber and Health
In addition to providing dietary fibers, foods rich in complex carbohydrates and fiber tend to be low in fat and contribute many other compounds such as vitamins, minerals, and phytochemicals that also may provide health benefits.

10. Intestinal Function
Insoluble fibers absorb water resulting in a larger, softer stool that is faster and easier to eliminate, which can help with:
Constipation
Hemorrhoids
Diverticular disease
Intestinal Function
Insoluble fibers provide many health benefits in the digestive tract. Insoluble fibers absorb water resulting in a larger, softer stool that is faster and easier to eliminate, which can help with constipation and hemorrhoids.
Diverticular disease is where there are protrusions or out-pouches in the wall of the colon. These pouches are believed to develop from excessive pressure, which weakens the wall of the colon. In many cases, there are no obvious symptoms, but in some people the diverticula become inflamed and painful. Insoluble fibers may help prevent diverticular disease by absorbing water making a larger, softer stool that requires less pressure to move through the digestive system.

11. Colon Cancer
Both insoluble and soluble fibers may protect against colon cancer
Insoluble fibers absorb water making a larger, softer stool which can:
Dilute potential carcinogens
Reduce transit time so the colon is exposed to any cancer causing substance for less time.
Soluble fibers can bind bile acids, potential carcinogens, and increase their excretion.
Colon Cancer
Both insoluble and soluble fibers may protect against colon cancer. Insoluble fibers absorb water making a larger, softer stool. A larger stool can help dilute potential cancer causing substances in the intestine. Since a larger, softer stool moves through the intestine faster, the colon is exposed to any cancer causing substance for less time. Bile acids are released into the intestine to help with fat digestion. Bile acids can be converted into potential cancer causing substances in the intestine. Soluble fibers can bind bile acids and increase their excretion.

12. Heart Disease
As mentioned, soluble fibers can bind to bile acids and increase their excretion.
With fewer bile acids in the intestine, less fat is absorbed.
Also by increasing bile acid excretion, the liver must use its cholesterol to make new bile acids.
Heart Disease
Soluble fibers may have a role in lowering blood cholesterol. As mentioned, soluble fibers can bind to bile acids and increase their excretion. With fewer bile acids in the intestine, less fat is absorbed. Also by increasing bile acid excretion, the liver must use its cholesterol to make new bile acids.

13. Diabetes Soluble fibers may have a favorable effect on blood glucose.
Soluble fibers decrease the rate at which food is released from the stomach and delays glucose absorption into the blood.
This may help prevent wide swings in blood glucose throughout the day.
Diabetes
Soluble fibers may have a favorable effect on blood glucose. Soluble fibers decrease the rate at which food is released from the stomach and delays glucose absorption into the blood. This may help prevent wide swings in blood glucose.

14. Weight Management
Foods rich in complex carbohydrates tend to be low in fat and added sugars which can help with weight management by providing fewer calories.
In addition, as fibers absorb water they swell up creating a feeling of fullness and delaying hunger.
Weight Management
Foods rich in complex carbohydrates and fiber tend to be low in fat and added sugars which can help with weight management by providing fewer calories. In addition, as fibers absorb water they swell up creating a feeling of fullness and delaying hunger.

15. How Much Fiber
The National Research Council set a Dietary Reference Intake (DRI) for dietary fiber.
An adequate Intake (AI) for dietary fiber was set at 14 grams dietary fiber per 1,000 calories.
Thus for a reference 2,000 calorie diet recommended intake would be 28 grams per day.
How much Dietary Fiber
The National Research Council set a Dietary Reference Intake (DRI) for dietary fiber. An adequate Intake (AI) for dietary fiber was set at 14 grams dietary fiber per 1,000 calories. Thus for a reference 2,000 calorie diet recommended intake would be 28 grams per day.

16. Too Much Fiber
Dietary fiber can bind some minerals and decrease their absorption. However, if mineral intake is adequate a recommended dietary fiber intake will not compromise mineral balance.
Fiber intake is like all nutrients - “more” is not always “better.” Consuming a diet that provides a variety of nutrients is the key.
Too Much Fiber
Dietary fiber can bind some minerals and decrease their absorption. However, if mineral intake is adequate a recommended dietary fiber intake will not compromise mineral balance. Fiber intake is like all nutrients in that “more” is not always “better.” The importance of consuming a diet that provides a variety of nutrients is the key.

17. Food Sources of Fiber
Foods are the best source of fiber, get both soluble and insoluble fiber.
Food sources of fiber include fruits, vegetables, whole grain products, legumes, nuts and seeds.
Cooking processing and removing peels can lower fiber content.
Food Sources of Fiber
Foods are the best way to increase fiber intake. Food sources of fiber include fruits, vegetables, whole grain products, legumes, nuts and seeds. Cooking, processing, and removing peels can lower the fiber in foods.

18. Tips for Increasing Fiber
Increase fiber slowly. Increasing fiber too fast may cause bloating and gas.
Since some fiber absorbs water it also is important to drink plenty of fluids when increasing dietary fiber.
Tips for Increasing Fiber
It is important to increase fiber in the diet slowly. Increasing fiber too fast may cause bloating and gas. Since some fiber absorbs water it also is important to drink plenty of fluids when increasing dietary fiber. 

19. Tips for Increasing Fiber
Increase fiber in the diet slowly. Increasing fiber too fast can cause bloating and gas.
Because fibers absorb liquids drink plenty of fluids when increasing fiber.
As with all nutrients, “more” is not “better.” Moderation is the key.