Fiber is a type of carbohydrate found in plant foods. Unlike other carbohydrates, the body can’t digest fiber. Instead, fiber passes through the
body, performing important functions in the process. The type of function performed depends on the type of fiber consumed. Plant foods contain two types of fiber—soluble and insoluble.
Soluble Fiber – This type of fiber dissolves in water and slows the digestion of glucose, the basic form of sugar used by the body for energy. It can lower blood sugar levels and can help lower blood cholesterol.
Good food sources of soluble fiber include apples, artichokes, asparagus, bananas, barley, beans, berries, broccoli, Brussels sprouts, dark leafy greens, legumes, lentils, nuts, oats, pears, peppers, and squash.
Insoluble Fiber – This type of fiber absorbs water, but does not dissolve in water. It helps move food and waste through the digestive system, which promotes regular bowel movements and prevents constipation.
Good food sources of insoluble fiber include bran, carrots, cucumbers, legumes, nuts, seeds, tomatoes, and whole grains.
Consuming too little fiber can cause high blood sugar levels, stomach or abdominal pain, and tiredness or nausea after eating. On the other hand, a diet high in fiber reduces the risk of certain conditions like heart disease, diabetes, cancer, hemorrhoids, and irritable bowel syndrome (IBS).
In order to get the full benefits of fiber, plant foods must be eaten in their whole form, or close to their whole form.
While fresh fruit and vegetable juices contain vitamins and minerals, they do not contain the beneficial fiber found in their source foods.
Increasing Your Fiber Intake – The Dietary Reference Intake for dietary fiber (soluble and insoluble fiber, combined) for adults is 38 grams for males 18-50 years old and 30 grams for those 51 and older. The recommendation for females 18-50 years is 25 grams of fiber per day and 21 grams for women 51 years and older .
Source:2017 The Institute for Functional Medicine