Fiber. You hear about it all the time, but do you know exactly what it is and why it’s a vital component to a healthy diet? Today I’m breaking down fiber so you can be confident in what it is, where it comes from and why you should consume it every day!
Most americans fall short in meeting the recommended Adequate Intake of fiber daily. It is recommended to consume 14 grams of fiber per every 1000 calories consumed. (~28 grams per day for women, 35 grams for men, however it is thought that our actual requirements are higher).
What is Fiber?
Simply put, fiber is a carbohydrate and part of a plant such as fruits or vegetables, grains, nuts, seeds, and legumes that is not digested in the body. It provides bulk for the stool, helps adsorb toxins and cholesterol from the diet, and is like the “broom” of our digestive system. It’s important for satiety, regulating blood sugar, and provides prebiotic food necessary for our healthy gut bacteria to thrive and outnumber the harmful bacteria. It also has been shown to promote weight loss due to it’s beneficial effects.
Types of Fiber
Fiber is categorized as either dietary fiber, meaning it comes from the real food itself and remains intact, or functional fiber, which is isolated fiber shown to be beneficial and added into food products. Dietary fiber is defined as an indigestible carbohydrate or lignin that is fully intact and found in plants. Functional fibers are beneficial fibers that have been either isolated, extracted or manufactured and added to food products. When you see fiber on a food label, the total number in grams represents both naturally occurring dietary fiber and functional fiber.
Fiber is also categorized as soluble or insoluble. Insoluble fibers are “insoluble” in water and consist of cellulose, hemicellulose and lignin. They provide the bulk of the stool and are large contributors to healthy elimination daily. These fibers are mostly found in bran, whole grains, legumes, nuts, peas, mature root vegetables (i.e. carrots), outer covering of seeds, fruits with edible seeds such as berries, and other green vegetables and fruits. Lignin consists of the structural component found in plants, such as in the stems and seeds. This fiber like many others is considered a dietary and functional fiber, as it is found naturally occurring in plants but may also be isolated to add fiber to a food product.
Soluble fibers are water soluble (hence the name) and form a viscous gel, slowing down digestion and boosting satiety. Soluble fiber is found in oat bran, barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables. It is also found in psyllium husk, which is a common fiber supplement. Soluble fiber such as beta glucans found in oats are highly fermentable (benefit the gut bacteria) as well as help trap dietary cholesterol and eliminate it from the body, contributing to lower LDL cholesterol and may aid in lowering serum triglycerides. Soluble fiber and it’s high fermentability is beneficial to short chain fatty acid production and the growth of health promoting bacteria.
More Benefits
Viscous gel forming fibers such as soluble fibers are also excellent for blood sugar regulation. Because there is a delay in stomach emptying and increased distention from fiber in the stomach, there is a slower rise in glucose into the bloodstream. This creates a better glycemic response after a meal. There is also an inverse relationship between the intake of fiber and the development of Type 2 Diabetes.
Fiber may also increase satiety inducing hormones like CCK, GLP-1, and PYY, and may reduce the hunger hormone ghrelin. The higher volume and lower calorie contribution of fiber rich foods help to create a feeling of fullness and improve weight control.
Diets high in fiber have also been associated with lower risk of colon cancer, however the specific mechanisms are still unclear. It is proposed that fiber binds to pro-carcinogens and carcinogens in foods and expels them from the body. Fiber also increases transit time in the colon, reducing the exposure of dietary carcinogens to the colonic lumen. Inadequate fiber intake is also associated with constipation and development of diverticulosis, or pouches that develop in the colon when the colon wall weakens. Trapped food particles in these pouches usually lead to inflammation of the area, known as diverticulitis.
Now that you know where you can find fiber, what it is and it’s benefits, I hope you are more inclined to choose a healthy fiber filled snack such as a fruit or vegetable over a bag of chips! Aiming for at least half of your plate as vegetables also helps you to meet and even exceed your daily fiber recommendations. If you don’t eat much fiber now, start with smaller quantities and work your way up, and don’t forget to stay hydrated!
In good health,
xo Samantha
