Fiber is consistently reported to be essential as part of a healthy diet. Soluble fiber has been shown to help lower blood cholesterol; however, insoluble fiber doesn’t seem to help lower blood cholesterol. Compared to other grains, oats have the highest proportion of soluble fiber; this is why oats are commonly recommended as part of a heart-healthy diet. However, keep in mind that most commercial oat bran products are overly processed and contain very little bran; plus they can be very high in saturated fat and sodium, so read the labels carefully. Other foods that are high in soluble fiber include beans, peas, barley, rice bran, strawberries, citrus fruits, and apple pulp.
Insoluble fiber is important in aiding normal bowel function, which is important in preventing constipation and reducing the risk of diverticular disease. Constipation is the most common gastrointestinal complaint in the U.S. and is a particular problem for the elderly. Foods that are high in insoluble fiber include, whole-wheat bread, wheat bran, whole-grain cereals, rice, rye, barley, beets, carrots, cabbage, Brussels sprouts, cauliflower, turnips, and apple skins.
Ideally, you should get your fiber from food. If you need to take a fiber supplement, make sure to first consult your healthcare provider, as fiber supplements can interact with certain medications. Specifically, individuals taking tricyclic antidepressant medications, diabetes medications, cholesterol-lowering medications, digoxin to regulate heart function, lithium, or penicillin should consult with their healthcare provider before taking fiber supplements because the fiber might interfere with your body’s ability to absorb these types of medication.
Fiber’s Effect on Heart Disease
Numerous large research studies have found that having a diet high in fiber has been linked to a reduced risk of heart disease. A Harvard study of more than 40,000 male health professionals concluded that consuming a diet high in total fiber was associated to a 40 percent reduction in the risk of coronary heart disease compared to a diet low in fiber. The cereal fiber found in grains appeared to be the most beneficial. Similar results have been found with females.
Fiber intake has also been linked with metabolic syndrome, a combination of factors (including high blood pressure, high insulin levels, elevated triglycerides, low levels of HDL cholesterol (the good kind), and excess weight – especially in the abdomen. Several studies suggest that higher intake of fiber may somehow reduce the risk of this increasingly common syndrome.
Fiber’s Effect on Colon Cancer
A high fiber diet has been promoted for years to help reduce the risk of colon cancer. This recommendation was based on results from small studies. In more recent years, larger studies with better designs have not shown a link between fiber and colon cancer. However, just because fiber may not play much of a role in preventing colon cancer doesn’t mean that it isn’t important in preventing other colon-related disorders.
One of the most common disorders of the colon is diverticulitis – an inflammation of the intestine. It is estimated that one-third of adults over the age of 45 and two-thirds over the age of 85 in North America have this disease. In a long-term follow-up study of male health professionals, consuming insoluble fiber was associated with a 40 percent reduced risk of diverticular disease.
Fiber’s Effect on Type II Diabetes
Type 2 diabetes is the most common form of diabetes, accounting for 90-95% of all diabetes. It is primarily related to lifestyle factors. Recent studies of both male and female health professionals have found that a diet high in cereal fiber was linked to a lower risk of type 2 diabetes. The glycemic index (GI)of foods also plays a role with this form of diabetes. Harvard studies of health professionals found that a diet high in high-GI foods and low in cereal fiber more than doubled the risk of type 2 diabetes compared to diets low in high-GI foods and high in cereal fiber.
The Bottom Line:
Eat more fiber! If your current fiber intake is low, add in fiber-rich foods gradually. Adding them in too quickly can cause discomfort and digestive difficulties. Consuming more fiber also requires you to drink more water – another healthy habit.
Sources: American Heart Association; Harvard School of Public Health; University of Maryland Medical Center
