The Ultimate Guide
to Fiber in Food

Fiber plays a vital role in human nutrition and is a versatile ingredient in the grocery industry.  Unfortunately, few resources provide a comprehensive overview of fiber’s impact on our food and health. 

Here at AgriFiber, our mission is to bring sustainable, healthy, and fiber-centric ingredients to the food products you love. So, we’ve created Fiber 101 to answer some basic questions about this underappreciated ingredient.  

We hope you enjoy this journey as we uncover the sources and types of fiber, fiber’s clinically proven health benefits, and how fiber can make some of our favorite foods even more delicious.

What is Fiber?

The answer to this will depend on whom you ask, but to food scientists, fiber is a unique type of carbohydrate. This may surprise you because carbohydrates are often portrayed negatively, while fiber is universally viewed as healthful. We’ll need to dig a bit deeper into the chemistry to better understand why.

The word carbohydrate encompasses simple sugars and long chains of chemically linked sugars referred to as starch or fiber. Some carbohydrates, like common starches, are readily digestible by humans: Our bodies break down these molecular chains into their sugars, which fuel our cells similarly to the way a sugary drink would. Fibers are also long chains of sugars, but they are connected in a way that prohibits our bodies from converting them into simple sugars—they are not metabolized; the chains cannot be broken down.  

We will review the impact of this critical differentiating factor later, but in short, these unmetabolized molecular chains (fibers) regulate our digestive system, feed our gut microbes, and leave us feeling sated without a huge calorie load. Essentially, fiber has all the good stuff and none of the bad! 
1) Photosynthesis begins with, and is powered by, solar energy;plant leaves capture the sun's rays and use that power to fuel thephotosynthetic reaction.  
2) The photosynthetic reaction takes water and carbon dioxide andconverts those raw materials into simple sugars and oxygen using the sun'senergy. 
3) Photosynthesis's excess sugar is converted into starch andfiber, long molecular chains of small sugar subunits. While chemically similar,starch and fiber differ in how their sugar units are connected and physicallyorientated in space. This seemingly small difference becomes criticallyimportant in how our bodies treat these two nutritionally important substances. 
4) Our bodies can quickly break starch down into its simple sugarsubunits (the process of metabolism). Fiber's structure, on the other hand,prohibits metabolization. Instead, fiber travels uninterrupted to our guts,where it can sustain healthy gut bacteria populations (our gut microbiome).

How Much Fiber Should We Consume?

With fiber’s many positive health attributes, it’s no surprise that the medical community suggests significant daily fiber consumption: 21 to 25 grams per day for women and 30 to 38 grams per day for men (also stated as 14 grams of fiber per 1,000 kilocalories of food consumed).

Currently, however, daily fiber intake is roughly half of the recommended level—only about 15 grams per day.

It is AgriFiber’s mission to change that!

Types of Fiber: Soluble & Insoluble

Food scientists and dietitians categorize fiber in a handful of ways. While each categorization method has its pros, cons, and exceptions, the most common method is based on water solubility. 

“Water solubility” may sound technical, but it’s deceptively simple!  If something is soluble in water, it will dissolve in water.  If something is insoluble in water, it will not dissolve in water. It’s as easy as that!

With your newfound knowledge, it should come as no surprise that soluble fibers are those that dissolve in water and insoluble fibers are those that do not dissolve in water.  How dietary fibers interact with water changes how our body handles them as they move through our digestive tract and interact with our gut microbes. We’ll dive into the gut microbiome later on, but in general, fibers that are fermented by the microbiome are associated with numerous health benefits like immune functionality and mood regulation. Fibers that are not readily accessible to the microbiome yield other important health attributes like reduced blood cholesterol.

Soluble and insoluble fibers are almost always found together in the same plant-based foods but at different ratios. Not only do both types of fiber contribute to a healthy diet, but they also serve very different functions in foods. Fiber’s interaction with water is so critical that AgriFiber uses the soluble/insoluble distinction to separate its product line: Soluble fibers (SFC, SFO) and insoluble fibers (MFC, MFO), all of which are upcycled from the same crops. 

What is Functional Fiber?

You may have heard the word “functional” to describe ingredients or foods. This terminology can be confusing because “functional” carries two different colloquial meanings.  A food or ingredient can be deemed “functional” by contributing specific health properties. For example, AgriFiber’s soluble fibers (SFC and SFO) are functional because of their proven prebiotic effect. The term “functional” can also describe ingredients that impart specific physical properties to food.  For example, AgriFiber’s insoluble fibers (MFC and MFO) are functional because of their ability to modulate a food’s texture, shelf life, and freeze-thaw stability.

These two definitions of “functional” are not mutually exclusive–an ingredient can be none, one, or both of these things. A great example of this is AgriFiber’s soluble fiber, SFC, which is both a clinically-backed prebiotic and has been shown to enhance the mouthfeel of indulgent, whipped desserts.

Fiber in the Diet

Where do we consume fiber in our diets?

Dietary fiber predominantly originates from plant-based foods. Recall our earlier definition of fiber as long, unbreakable molecular chains of sugar molecules.  Sugar is the starting material for all carbohydrates (fibers and starches), and plants produce sugar via photosynthesis.  Photosynthesis converts water and carbon dioxide into sugar and oxygen using energy from the sun. Like people, plants use sugar as their energy source. Plants also use sugar molecules to assemble fiber, which provides physical structure by imparting shape, rigidity, and flexibility.

So unless a plant-based ingredient were processed (refined) to remove its fiber, dietary fiber would be a component of all plant-origin foods (fruit, vegetables, legumes, and grains).  Dietary fiber can also be extracted from plants and used as an ingredient in its pure form (like psyllium husk or any of AgriFiber’s ingredients).  When you see “added fiber” on the food label (like corn fiber or oat fiber), it is often added from a pure plant extract.  

Scientists have also developed techniques for manufacturing dietary fiber synthetically. We briefly describe and provide examples of natural and synthetic fiber below.

Where Does Fiber
Come From?

Most fiber comes from plant sources; dietary fiber comes from edible plants. Unless the fiber was purposefully removed from foods through processing, dietary fiber is found naturally in all plant-based foods we eat (like an apple or corn flour). Dietary fiber can also be extracted from plants to use as an ingredient in its pure form (like psyllium husk or Agrifiber MFC). Over the past several decades, a variety of industries, including the food industry, have developed synthetic fibers in the lab. We briefly describe and provide examples of natural fiber, synthetic fiber, and supplemental fiber. 

Natural Fiber Sources

Fiber is naturally formed by the plant to provide the stems, roots, and seeds with rigidity and strength that allow the plant to grow, develop, and protect itself from pests. Some of the most common natural sources of fiber include, but are not limited to: 

Grains: oat, wheat, corn, rice, barley, sorghum
Fruits: bananas, berries, apples, pears, mango, guava, melon, peaches, plums, oranges, and persimmons
Vegetables: green leafy vegetables, carrots, beets, broccoli, artichokes, and root vegetables
Legumes and pulses: pinto beans, navy beans, black beans, peas, lentils, and lima beans
Seeds and nuts: chia seeds, flax seeds, poppy seeds, pumpkin seeds, chestnuts, sesame seeds, almonds, walnuts, and peanuts

The fiber in many of the foods above can be extracted and utilized as an ingredient in food formulations. This is called added fiber.

Synthetic and Fermented Fibers

Food scientists have access to a family of synthetic fibers, which come in two forms:

1. Fibers synthesized without recognizable agricultural starting materials, and
2. Fibers that originated from plant materials but were subjected to significant post-extraction chemicals or enzymatic processing/modification.

Synthetic and modified dietary fibers include fructooligosaccharides (FOS), galactooligosaccharides (GOS), and some cellulose-based gums.  Many fantastic reports are available to help consumers learn more about how the fiber they consume is produced–the FDA, for example, routinely reviews the best science available and publishes updated guidance on their findings.

Fiber Upcycling

Upcycling is the value-added repurposing of a commercial waste stream that would otherwise be discarded or used as scraps.

Upcycling is a growing trend in the food industry. Companies are increasingly looking for ways to divert their waste streams–or even other companies’ waste streams–for recapture and conversion into high-quality food products. 

Sustainability is a core tenant of AgriFiber’s mission, and recursive upcycling is the primary tool AgriFiber uses to achieve its sustainability goals. We will unpack AgriFiber’s upcycling process as a broad demonstration of fiber upcycling in the ingredient industry.

Many industrial processes exist where crops–particularly grains–have their fibrous components removed. For example, fiber-rich hulls need to be removed from corn grown for ethanol or cornstarch production; the starch is the valuable component, and the fiber gets in the way. These fibrous hulls would be sent to landfills, composted, incinerated, or mixed with animal feed. Instead, AgriFiber diverts these corn hulls and transforms them into a range of novel, functional ingredients. AgriFiber’s upcycling process is particularly unique in that AgriFiber reprocesses its waste stream to extract even more valuable ingredients, hence the term recursive upcycling.

Upcycling fibers eliminates the need to dedicate farmland explicitly for fiber production–instead, it takes advantage of the residuals from other production processes. It is a highly scalable and essential technique in making global food production more environmentally sustainable. 

Fiber Supplements

Fiber supplements are a popular choice for people looking to increase their fiber intake. Fiber supplements usually come in powder or pill form and contain a selection of extracted and synthesized fibers offering a wealth of health benefits. We provide more information about the health benefits of fiber below!

What are the Nutritional and Health Benefits of Fiber?

We all know that dietary fiber is an integral part of a balanced diet, but dietary fibers range of positive health attributes is more extensive than you may realize.

Supports Heart Health

Some types of dietary fiber can improve imbalances in blood lipids, including conditions like high blood cholesterol and triglycerides (dyslipidemia). According to research published in the Journal of the Academy of Nutrition and Dietetics, supplementation with certain fibers like beta-glucan and psyllium decreases “bad” cholesterol (LDL).

The Linus Pauling Institute explains that these viscous fibers help trap the bile released into the small intestine soon after eating, inhibiting the reabsorption of bile. Since our liver makes bile from cholesterol, this increased loss of bile in stool causes more bile to be made, which helps lower “bad” blood cholesterol levels.

Regulates Blood Glucose Levels

High blood glucose levels are associated with metabolic diseases like metabolic syndrome and type 2 diabetes. Research published in the American Journal of Clinical Nutrition demonstrates that the consumption of soluble, viscous fiber can help stabilize levels after meals when blood glucose spikes are most likely to occur. Soluble, viscous fibers like AgriFiber’s SFC positively impact glycemic control in part by increasing the viscosity of the chyme or partially digested food that enters the small intestine. 

Lowers Blood Pressure

High blood pressure is associated with heart disease and cardiovascular events like heart attacks and stroke. An analysis of data from the 2004-2014 US National Health and Nutrition Examination Survey found that those who consume more significant amounts of fiber from grains, vegetables, or other fiber-rich foods, had a lower risk of hypertension. While more research needs to be carried out to understand the impact of fiber from supplements or diet on blood pressure, all current research points to the benefits of fiber consumption for blood pressure regulation.

Improves Digestive Regularity

One of the best-known benefits of fiber consumption is its impact on digestive health; more specifically, it helps to improve the regularity, consistency, and ease of stool elimination.

Fiber has two main mechanisms of action on digestive regularity, as described by the Linus Pauling Institute at OSU. First, insoluble fiber helps to stimulate the secretion of water and mucus in the intestine, allowing stool to pass more quickly. Second, soluble, viscous fibers help prevent water reabsorption from stool back into intestinal walls, resisting constipation.

Supports Beneficial Gut Microbes

Prebiotic fibers, or fermentable fibers, act as food for probiotic bacteria. The Academy of Nutrition and Dietetics states that the gut microbiome of healthy individuals plays a vital role in food digestion, displaces pathogenic bacteria, and is essential in complex metabolic systems that support nutrition, digestive, brain, and immune health.

What Are the Applications of Fiber in the Food Industry?

Fiber is best known by the general population for its nutritional and health benefits. However, modern food technology has significantly expanded fiber’s functional applications. AgriFiber’s product line, for example, provides a litany of functional behaviors ranging from the improvement of a food’s organoleptic properties to a formulation cost reduction tool. 

Provided below is an extensive (if not comprehensive) list of functions that fiber can perform in foods.  These functions are an active focus of academic research; we at AgriFiber are excited to watch this list grow!

Some of the technological properties of added fibers include: 

Water/Oil Holding
Textural/Viscocity Modification
Gel Formation
Improved Mouthfeel
Moisture Control
Shelf-Life Extension
Yield Increase/Cost Reduction
Improved Fried Coatings
Water holding, swelling, and retention

Film Forming
Ingredient Suspension
Flavor enhancement
Freeze-Thaw Stability

AgriFiber’s ingredients do all of these things and more!

Fiber on Your Label

Clean Label

While no standard industry definition for “Clean Label” exists, it is generally understood that Clean Label products contain few ingredients that are easily recognizable by the average consumer. Some forms of added fiber, like AgriFiber’s entire line of ingredients, are easily identifiable by the consumer and are viewed as Clean Label.

Source and Type

There are two places grocery labels divulge more information about a food’s fiber content. 

The first is the nutrition facts panel. The nutrition facts panel reports the amount of total dietary fiber per serving. It doesn’t differentiate the fiber intrinsic to the food’s primary ingredients from added fiber sources.

If consumers want to learn whether the product has added fiber, they can look at the ingredient list. Common added fibers include bran, gum, inulin, psyllium, pectin, and beta-glucan. 

You’ll have to do your own research for more information about a particular type of fiber (such as whether it is fermentable, soluble, or insoluble).  We hope Fiber 101 is a valuable tool in this regard!

Main Takeaways

Fiber is essential to human health. Long before the term 'dietary fiber’ came into our lexicon, fiber contributed to our wellbeing, feeding our gut microbes and providing cholesterol-wicking properties in the intestines. 

Unfortunately, most people eating a Western-style diet don’t consume enough fiber. People are missing out on benefits like lower cholesterol, stable blood glucose, and promoting beneficial microbes. The food industry can improve dietary fiber consumption by adding fiber during the food manufacturing process. Not only does added fiber help increase consumers’ fiber intake, but it also provides numerous functional benefits for the food manufacturing process itself. 

Do you have any questions about AgriFiber’s fiber ingredients or fiber in general? Please don’t hesitate to reach out; we’d love to chat more and help with any questions you may have! 
Do you have any questions about Agrifiber MFC or other Agrifiber MFO, or Agrifiber BFG? Please do not hesitate to reach out and share what you are thinking. We’d love to chat and answer any questions you may have!
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