Although all prebiotics are fibers, not all fibers are prebiotic. This means that on top of making sure that you’re getting enough fiber in general, it can also be essential to ensure that you’re also getting the right types of fiber. Here we discuss the health benefits of prebiotic fiber.
A plethora of scientific and nutritional research suggests that adequate consumption of prebiotic fiber can make all the difference between supporting your immune system’s healthy functioning or impeding it. However, for a fiber to be considered prebiotic, it has to fulfill three core requirements (1):
- that it is not digestible by the small intestine
- that it is fermented and used by good bacteria within the microbiome
- that it produces measurable benefits to health and well-being
What is the microbiome?
The microbiome is the name for the collaborative system of micro-organisms covering our bodies from head to toe. These micro-organisms include bacteria, archaea, viruses, and fungi and are responsible for 99% of the total genetic information we contain as human beings.
The highest microbes concentration (around 100 trillion) resides in our gastrointestinal tract, aka the gut. When the bacteria in our gut receive the correct nourishment (aka prebiotic fiber), they become well-equipped to support a healthy immune system by converting these fibers into a compound referred to as short-chain fatty acids (SCFA) (2).
A greater rate of conversion for SCFA is linked specifically to a large range of healing implications, such as the reversal of insulin resistance, high cholesterol, overall digestive function, disease immunity, and even a better mood (3, 4, 5).
For this reason, it makes sense that the foods we eat can have one of the single greatest impacts (next to only antibiotics and disease) on the health of our microbiome — and, therefore, the health of our entire body, too.
This article will cover five different types of fiber, each with its own set of prebiotic effects and implications within the body:
- Guar Gum
- Larch Arabinogalactan
- Fructooligosaccharides (FOS)
- Chicory Inulin
Guar gum — also frequently packaged as Partially Hydrolyzed Guar Gum, or PHGG — is a powdery, white, tasteless, water-soluble, natural dietary fiber made from guar beans, aka cluster beans.
Research on guar gum demonstrates its high effectiveness as a prebiotic through the promotion of growth in helpful bacteria such as lactobacilli and bifidobacteria, and increasing the presence of SCFA within the gastrointestinal tract (6).
These microbial reinforcements then work to strengthen the immune system, reduce bloating, decrease the risk of potentially fatal diseases, and reduce symptoms for individuals who may suffer from digestive disorders such as IBS (7, 8).
These effects occur as a result of the fermentation process, which allows for the guar gum fiber to be converted into SCFA and used as an energy source for the type of cells — namely, epithelial cells — that are necessary for the regulation of metabolism, gut physiology, and immunity, among other vital processes (9).
This type of prebiotic fiber, arabinogalactan, has been eaten by humans for thousands of years and has earned approval by the FDA for its impressive and widely studied list of health advantages.
Arabinogalactan can be found in high quantities in the seeds, fruit, leaves, roots, and sap of a wide variety of different plants. The most common commercial source of arabinogalactan derived from the North American larch tree pictured above (10).
When it comes to larch arabinogalactan’s impact on the body when consumed, research suggests that this prebiotic plays such a functional role in supporting the immune system that can even decrease the occurrence of common cold infections by up to 23% (11).
Numerous studies have also found larch arabinogalactan to be successful at promoting and protecting health on a cellular level, such as through the enhancement of natural killer (NK) cells, macrophages, and pro-inflammatory cytokines — all mechanisms designed to readily fight and prevent chronic disease (12).
One of the most potent and commonly found types of prebiotic fiber is fructooligosaccharides — and thankfully — FOS, for short.
FOS consists of short fructose chains with a mildly sweet flavor profile. But, unlike other sweeteners, FOS has no impact on blood glucose levels due to its indigestibility as a prebiotic fiber, which means it won’t contribute to a spike in insulin.
Even at fairly low levels of consumption (ranging between 5–8 grams per day), FOS has been linked to a significant increase in bifidobacteria activity within the colon, helping maintain the gut microbiome’s balance (13).
If you’re looking for dietary sources of FOS, foods such as bananas, chicory root, artichoke, garlic, and asparagus are all known to contain relatively high amounts of this prebiotic fiber (14).
Pectin is another type of water-soluble prebiotic fiber that supports a variety of vital functions within the body. For example, research shows that pectin helps reduce the body’s glycemic response by stalling the absorption of glucose and has also been linked to the lowering of LDL cholesterol and the risk of heart disease (15).
When pectin fiber reaches our gastrointestinal tract, it has the unique ability to be very quickly metabolized and fermented by the bacteria within our gut, which then converts it into short-chain fatty acids (SCFA) to be absorbed back into the bloodstream (16).
When this occurs, it can reduce and control appetite and allow our immune system to become stronger by feeding the type of bacteria in our gut, designed to effectively process fatty acids from the foods we eat (17).
Pectin can be found in relatively large qualities in various foods such as apples, strawberries, potatoes, carrots, lemons, and even some legumes and nuts!
One of the best sources of prebiotic fiber, inulin, comes from the chicory plant’s root. Chicory has a long history of medicinal and nutritional usage that can be traced back to the Roman Empire and Ancient Egypt.
Chicory has such an incredible reputation as a prebiotic fiber, namely because fiber comprises nearly 90% of its weight when dry, making it an excellent food source for bacteria within the microbiome (18).
As well as containing other types of fiber such as pectin and (hemi-)cellulose, chicory root is extremely high in one particular prebiotic fiber called inulin. Inulin has been rigorously studied for its positive association with energetic metabolism, insulin sensitivity, and a lowering of cholesterol (19, 20).
In addition to the effects outlined above that help to moderate appetite, increase digestive efficiency, and prevent the development of diseases such as type-2 diabetes and coronary heart diseases, research suggests that inulin from the chicory root may also exhibit qualities that aid in the protection of oxidative stress (21).
The takeaway, The Health Benefits of Prebiotic Fiber
Prebiotic fiber is a nutrient our body (rightfully) knows how to take very seriously. From strengthening our immune system to preventing pathogens and a build-up of free radicals from encouraging both short-term and chronic disease — prebiotics have our back.
The more we sponsor the right kind of microbial environment within our gut through the foods we eat and the supplements we take, the more our bodies reward us by continuing to foster our overall and on-going well-being.
From a bacterial perspective, that’s why adding prebiotic fiber to your diet, and daily routine can be considered a key step in providing your body with the best possible health outcomes.
You might be interested in “The Benefits of Digestive Enzyme vs Probiotics.”