Your Gut Needs Prebiotic Fiber to Thrive. Here’s How to Get More of It

Gaby Vaca-Flores, RDN, CLE, discusses why prebiotic fiber is crucial for digestive regularity, immune support, and more. Plus: the top foods with prebiotics you’ll want to eat to reap their gut-boosting benefits.

You’ve likely heard of probiotics, the good-for-you bugs that live within your digestive tract. But have you heard of prebiotics? Arguably just as important as probiotics, prebiotic fibers deliver a host of benefits. 

Consider this post a handy starter guide to prebiotic fiber. We’ll cover what it is, its key benefits, and how to boost your intake through prebiotic foods.

What Is Prebiotic Fiber?

Prebiotics are non-digestible substances that provide beneficial effects for the gut microbiome. For context, the gut microbiome is a collection of microbes, or probiotics, that carry out important functions for our overall health and live within the digestive tract. Some of these functions include:

Simply put, probiotics are beneficial gut bacteria, while prebiotics are the primers that help them grow and thrive.

Prebiotics are sometimes called prebiotic fibers, which can lead to some misconceptions regarding dietary fiber. Although there are overlaps between prebiotics and dietary fibers, they are not the same thing. Like prebiotics, dietary fiber is also non-digestible and provides digestive and gut health benefits. 

All dietary fiber comes from carbohydrates. However, not all prebiotics come from carbohydrates—though many types of prebiotics do.

There are several types of prebiotics, but some of the most well-known ones include:

  • FOS (fructo-oligosaccharides) 
  • GOS (galacto-oligosaccharides)
  • TOS (trans-galacto-oligosaccharides)

How Prebiotics Work

A healthy gut microbiome is shaped by prebiotics in a number of ways, but mainly via fermentation. Since prebiotics remain undigested, they are left to ferment by probiotics in the colon. The fermentation process allows for prebiotics to break down and release different types of short-chain fatty acids, known as SCFAs, that proceed to offer health benefits.

The main SCFAs that are produced by prebiotics include acetate, propionate, and butyrate.

For instance, the breakdown of prebiotics produces butyrate, which helps energize colonocytes, the cells that line the colon. Healthy colonocyte function is essential to maintain balance in the gut microbiome. 

Man on toilet for digestive regularity concept

Benefits of Prebiotic Fiber

Prebiotics exert benefits by feeding the good bacteria in the gut… but how exactly does that translate into benefits for overall health? 

Here are three key benefits of prebiotic fiber:

1. Gut Diversity and Digestive Regularity

Microbiota or bacterial diversity is a sign of a healthy gut. Meanwhile, poor diversity in the gut is often seen in people dealing with digestive issues, including irregularity. 

The composition of your gut bacteria is mainly affected by diet. But as we know, prebiotics can help fuel the growth of probiotics in the gut, which in turn helps promote diversity. 

In fact, a double-blind, randomized, placebo-controlled study revealed an increase in the Bifidobacterium and Lactobacillus probiotic species in participants who consumed prebiotic FOS in both small and large amounts.  

By improving the overall composition of your gut microbiome, prebiotics can then help ease common gut-related issues. For instance, FOS was shown in a clinical study to improve stool frequency in healthy female adults who consumed the prebiotic fiber daily compared to a placebo group.

2. Immunity Support

Experts believe that as much as 70 to 80 percent of the immune system lives in the gut. Given the influence of prebiotics on gut health, it’s no surprise that they can also affect the body’s defenses.

The immune system is powered by a variety of cells such as natural killer cells, effector T cells, and B cells. While it’s unclear how exactly prebiotics interact with these cells, researchers suggest that prebiotic activity, such as fermentation and short-chain fatty acid production, exert some effects on their function. 

For example, peptidoglycan, a product of prebiotic fermentation, has shown the potential to fortify the innate immune system against pathogens like Streptococcus pneumoniae and Staphylococcus aureus.

Additionally, butyrate has been observed to pause the activity of HDAC, a cell that can weaken other cells, like dendritic cell IL-12, that are integral to healthy immune system function.

3. Cognitive Support

Because of the gut-brain axis, prebiotics also have a hand in nervous system function. Their workings in the nervous system are not fully understood. However, researchers have investigated the promising effects of prebiotics on mood, memory, learning, and other psychological activities. 

In fact, a review of six clinical studies that evaluated the effects of prebiotics on cognition and mood in healthy adults found that certain types of orally supplemented prebiotics, like beta-glucan, can support healthy neurologic function. 

Another clinical study confirms that prebiotic supplementation (from non-starch polysaccharides) can have a beneficial impact on memory in healthy middle-aged adults.

Woman washing a tomato, one of the best foods with prebiotics

Foods with Prebiotics

Presently, there is not an official recommendation as to how many prebiotics one should consume in a day. To keep things simple, some experts recommend focusing on meeting your recommended daily fiber intake, as this can help boost your prebiotic intake. As a reminder, men and women should aim to consume 38 and 25 grams of fiber, respectively, on a daily basis. 

Prebiotics are naturally present in a variety of foods, namely plant-based fare like whole grains, vegetables, fruits, and certain nuts. 

Here’s a quick list of of foods with prebiotics:

  • Almonds
  • Artichoke
  • Bananas
  • Barley
  • Beans
  • Chicory
  • Chia seeds
  • Dandelion greens
  • Flax seeds
  • Garlic
  • Honey
  • Leeks
  • Onions
  • Rye
  • Tomatoes 
  • Wheat

Note: Although prebiotics are readily available in food sources, their concentrations are relatively low. Additionally, it’s estimated that less than 5 percent of people actually meet their recommended fiber intake. This means that most people are probably not consuming nearly enough prebiotics through diet alone, which is where supplementation can come in handy.

HUM’s Beauty zzZz Gummies deliver two grams of FOS prebiotic fiber, which can benefit the gut and colon lining, digestive health, and support stool movement. They also pack a clinically studied dose of melatonin (three milligrams) to provide a dual benefit of enhanced sleep quality.

The Takeaway

Prebiotics are fermentable fibers that benefit the gut microbiome to provide a cascade of health benefits. Nourishing your good gut bacteria and promoting digestive regularity are among the perks of consuming prebiotic fibers, which underscores why it’s so important to prioritize them in your diet.

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