Fiber for Optimal Health

Blog originally posted through WellCats Newsletter

Fiber is one of those food components we all know we need, we’ve heard it’s important for our health, but for many of us, that’s where our knowledge around fiber ends. However, fiber has been extensively researched and recognized for its many health benefits including helping with the prevention of heart disease, high cholesterol, reducing the risk of some cancers, and acting as an important component for maintaining gastrointestinal tract function and health.

Differences in Fiber

There are two primary classifications of fiber: dietary fiber and functional fiber. Dietary fiber, which is typically a non-digestible carbohydrate, is present in plants and consists of the part of a plant not capable of being broken down by our human digestive enzymes. Functional fiber is fiber extracted from non-digestible carbohydrates that has been added to processed foods. While there are several ways to classify fibers, the most common is around how they interact with water. Fibers that dissolve in water are considered soluble (hemicellulose, pectin, gums) and those that do not are designated as insoluble (cellulose, lignin, and some hemicelluloses). Generally, vegetables, wheat, and most grain products contain more insoluble than soluble fibers. Both soluble and insoluble fiber remain undigested and are therefore not absorbed into the bloodstream. So instead of being used by our body for energy, fiber is excreted. Most plant based foods contain both soluble and insoluble fiber with the amount of soluble/insoluble fiber present in each food varying. Key to maintaining adequate fiber balance is to consume both soluble and insoluble fiber regularly in order to achieve fiber’s many health benefits.

Soluble fiber forms a gel when mixed with liquid, and can be found in foods like grains, seeds, legumes, and fruits. Some of the functions of soluble fiber are to prolong stomach emptying, and decrease glucose absorption time so that sugar is released and absorbed more slowly in the body. Therefore, soluble fiber can help to be an important regulator for blood sugar in those with diabetes. The delay in gastric emptying also helps to increase satiety and can therefore be extremely beneficial when working to maintain moderation and caloric balance in the diet. Soluble fiber has also been shown to help lower total cholesterol and LDL cholesterol due to its ability to bind with fatty acids and cholesterol where they are excreted in the large intestine. Insoluble fiber, conversely passes through our intestines largely intact increasing fecal bulk. The primary role of insoluble fiber is to prevent constipation and promote healthy bowel function. Insoluble fiber removes waste through the colon in less time as well as helps maintain optimal pH in the intestines. Great sources of insoluble fiber include vegetables like dark leafy greens, fruit skins and root vegetable skins, as well as many whole wheat products.

Current Fiber Recommendations

The National Academy of Sciences Food and Nutrition Board, which established Dietary Reference Intakes recommends a blend of both functional and dietary fiber for men aged 19-50 years of 38 grams total fiber per day and for men 51+, 31 grams is recommended. For women aged 19-50 years, 25 grams total fiber is recommended and 51+ a total of 21 grams per day is advised. Children aged 1-3 require 19 grams and 4-8 years 25 grams per day is suggested. In order to maintain a variety of fiber the Food Guide Pyramid encourages at least 5 servings of fruits and vegetables per day as well as a minimum of 2-3 servings of whole grains per day. This will help ensure maximum benefits from fiber consumption are obtained for a healthier population.