Fiber

Although there is no established RDA for fiber, groups such as the National Cancer Institute and the American Dietetic Association suggest that adults consume 25 grams daily from sources like whole-grain foods, fruits and vegetables, and dried beans. Most people consume about 12 to 15 grams a day. The protective effects of fiber are associated with eating fiber-rich foods and not with taking fiber supplements. As you increase your intake of fiber, you generally tend to decrease your intake of total fat and calories, perhaps providing an even greater measure of protection against heart disease.

There are two kinds of fiber:

• Insoluble fiber: This undigested fiber forms the roughage that promotes regularity and prevents constipation. Insoluble fiber can prevent constipation, diverticulitis, and irritable bowel syndrome. Insoluble fiber draws fluid into the large intestine, creates bulky stools which induce more rapid evacuation. Thus insoluble fiber helps propel fecal material out of the body more quickly.
  
• Soluble fiber: This form of fiber helps prevent heart disease and helps with the management of diabetes. Soluble fiber slows the rate of glucose (sugar) absorption, which is important for people with diabetes. Soluble fiber lowers the rate of cholesterol uptake, resulting in a reduction of the risk of cardiovascular disease. Soluble fiber also slows down the absorption of glucose and thus reduces the need for insulin.

Eating bulky, high-fiber foods can also help with weight control. Fiber, especially when it is saturated with water, fills you up without adding calories. Foods with fiber also take longer to chew, which helps slow down the rate at which you eat. Beans are one of the best sources of fiber, but they are not as popular in the United States as they are in other countries.

Research shows people over age 50 are more likely to eat breakfast than young adults are. And those who start the day with a bowl of fortified cereal tend to consume more fiber and calcium but less fat than people who have other foods for breakfast. Fortified cereals provide a more concentrated source of micronutrients than any other food in older adults' diets. Cereal eaters are also more likely to consume fruit juices.