The world of nutrition is always changing. Across the web, we see flip-flop concepts (meaning they go back and forth about whether a food or nutrient is good or bad) and a wide range of information about nutrients. You’d think it’d be safe to say that consuming recommended amounts of our core nutrients would ‘do the trick’ for satisfying nutritional needs. I’m sorry to say that this may no longer be the case with fiber. It turns out that not all fiber is created equal, yet the total fiber in a product will be totaled on a nutrition label. Let’s examine the difference between naturally present and isolated fiber in foods, what makes fiber different from other fiber, effects, and the names of isolated fibers.

Our body needs fuel and carbohydrates provide fuel for the body and brain through the three forms: simple carbohydrate, complex carbohydrate, and fiber. Fiber, unlike complex and simple carbohydrate, cannot be digested by humans because the bonds comprising it cannot be broken down by digestion. This is true for all fiber types. The simplest way to state the difference between natural fiber and isolated fiber is as follows: natural fiber you will find in food without manipulation and an isolated fiber you will find in food because it was added. Dietary fiber is defined as “non-digestible soluble and insoluble carbohydrates, and lignin that is intrinsic and intact in plants.” Isolated or synthetic fiber is defined as “non-digestible carbohydrates determined by FDA to have physiological effects that are beneficial to human health.”

It is true that manufacturers cannot simply put isolated/synthetic fiber into a product simply to fill space or for another reason, but it must prove to have physiological benefit(s). As stated earlier, all types of fiber are totaled and added to the nutrition label regardless of the fiber source or its properties. It may make you question, do different fibers exert the same effects? Do different fibers have equal nutritional value?

To begin answering the first questions, it must be stated that fiber is classified into three classes: solubility in water, viscosity, and fermentability. All fiber types influence health in some way and fiber does benefit health. Fibers with different qualities definitely overlap in names and functions. We don’t know more about fiber interactions within the human body because it’s difficult to study. There’s not much evidence that adding fiber to food has the same effects as eating foods naturally high in fiber. What we do know is that different natural fibers have different physiological effects, and many fiber-fortified foods contain only one type of fiber, not the range in naturally high-fiber foods. Keep in mind, it’s not indefinitely clear whether all or most of the benefits of a high-fiber diet, such as decreased risk of heart disease, come from fiber itself or the vitamins, minerals, and other compounds that accompany fiber.

Your health has a direct relationship with nutrition consumption, digestion, and absorption. A prime reason why people aim to buy and consume high-fiber foods is to keep regular. Cellulose is an example of fiber that is naturally occurring and helps constipation. Maltodextrin, often seen as an added fiber, won’t help much. Many isolated fibers lack the flexibility that natural soluble fibers have, which is key in their ability to function in controlling blood sugar and levels of cholesterol. Polydextrose and maltodextrin are isolated fibers that you can find in orange juice. They serve as a good example of isolated fiber that does not contribute nutritionally like fiber found naturally. On the flipside, consuming excess isolated fiber such as oligofructose and polydextrose can cause bloating, gas, and a laxative effect. Let’s be honest, it’s easier to eat too much ice-cream with added fiber than broccoli that naturally contains fiber.

Isolated fiber is definitely not all bad. It has shown to possibly be beneficial in the form of prebiotics. Prebiotics need to be further studies in order to confirm benefits. Prebiotics show promising results by stimulating the growth of healthy gut bacteria, which may have some health benefits. Also, adding insulin to foods may enhance satiety like natural fiber does. Bottom line, fiber-fortified foods are able to help boost an individual’s overall fiber intake, but they tend to be foods that are not nutrient dense. Aiming to consume a range of fiber is proving to be more beneficial than only consuming isolated or synthetic fiber such as the following: maltodextrin, polydextrose, oligofructose, galactooligosaccharide, insulin, high amylose starch, alginate, arabinoxylan, mixed plant cell wall fibers, pectin, guar gum, locust bean gum, psyllium husk, hydroxypropylmethylecllulose, beta-glucan soluble fiber, etc.

The biggest difference between natural fiber and isolated fiber is that isolated fiber usually contains only one type of fiber and it is manipulated to be put into a food it was not originally in. There is a lot more to learn about fiber and its physiological effects on humans. Natural and isolated fibers come in many forms and have a range of names. It is true that there are nutritional differences between natural and isolated fiber because some may have different physiological effects. It is important to know that the total fiber on the nutrition label is analytical; it is simple the totaled fiber in the product without regard to its source or properties. Isolated fibers are typically added to less nutrient dense foods. It appears eating fiber-rich unprocessed foods like whole grains, legumes, vegetables, and fruit may be most beneficial. Not all fiber is created equal.

 

Sources:

Fda.gov. (2019). Questions and Answers on Dietary Fiber. [online] Available at:

https://www.fda.gov/food/labelingnutrition/ucm528582.htm [Accessed 28 February. 2019].