When it comes to gut health, there’s a lot of hype about probiotics – but what about the benefits of prebiotics? Research on prebiotics is expanding rapidly, but studies show promising results. By consuming prebiotic foods, you may reduce your chance of developing chronic diseases like type 2 diabetes.

So what exactly are prebiotics? Prebiotics act like fertilizer for beneficial bacteria in your gut. They provide food for these bacteria and enable them to thrive. You can find them in foods like Jerusalem artichoke, banana, and oats. Probiotics, on the other hand, are microorganisms that are beneficial for gut health.

Multiple studies back up the evidence on probiotics, but research into prebiotics is relatively new. We’ll take a closer look at what the science tells us about the benefits of prebiotics and weigh up the evidence so far. Plus, find out five ways to improve gut health and ‘what is leaky gut?’ here at Live Science. And if you want to give probiotics a try, but not sure which products are right for you, have a look at our buying guide on the best probiotics.

1. Support gut health

Prebiotics are proven to play an essential role in supporting gut health. They provide food for the beneficial bacteria in your gut and cultivate diverse gut flora, associated with a reduced risk of chronic health conditions.

“There are literally thousands of types of bacteria that live in the gut, and they don’t all survive off the same nutrients,” says Debbie Petitpain, MS, RDN, and spokesperson for the Academy of Nutrition and Dietetics. “Prebiotics, therefore, influence the growth of some bacteria over others. They influence the overall gut microbiome or the complex community of microorganisms that live in the digestive tract.”

When prebiotics ferment, they produce beneficial molecules called Short-Chain Fatty Acids (SCFAs). According to the International Scientific Association for Probiotics and Prebiotics (ISAPP), these compounds are crucial for gut health and can inhibit inflammation, which is associated with a higher risk of disease.

2. May ease constipation

If you experience constipation, prebiotics may provide the relief you need. According to ISAPP, prebiotics regulate bowel movements and can ease symptoms of constipation.

Yet if you have a diagnosis of IBS, the evidence is mixed. A 2020 review in Experimental and Therapeutic Medicine found that prebiotics could alleviate constipation in people with IBS. Yet a 2021 study in Nutrients suggests the evidence is too limited to draw conclusions. Bloating and gas are known side effects of prebiotics, so you’ll want to start small if you’re prone to these symptoms.

3. May make you feel fuller

Want to lose excess weight? You may have heard claims that prebiotics reduce cravings and make you feel full, which can help with weight loss. The good news is that there is emerging evidence to support this view. A trial published in the American Journal of Clinical Nutrition showed that oligofructose, a type of dietary fiber found naturally in foods like onions, Jerusalem artichoke, leeks, garlic and oats, suppresses the hunger hormone ghrelin in overweight adults.

4. May improve mineral absorption

Minerals are a crucial part of a healthy diet. Yet consuming minerals is only half the story — your gut needs to absorb these minerals to reap the full benefits. According to the Academy of Nutrition and Dietetics, prebiotics can improve the absorption of minerals like calcium which is essential for strong teeth and bones.

5. May regulate blood sugar

If you have diabetes, regulating blood sugar can help manage your symptoms. According to ISAPP, prebiotics are associated with improved blood sugar control. A 2019 review of 33 studies in the Journal of Translational Medicine showed that taking prebiotics reduced fasting blood sugar levels and decreased HbA1c, a marker of blood sugar control.

Yet questions remain about the extent of the impact of prebiotics. A 2021 trial found that six weeks of prebiotics made little difference to fasting glucose levels in people with type 2 diabetes. The researchers concluded that a longer duration might be necessary to affect blood sugar levels.

6. May boost immune function

It’s no surprise that immunity is an area of increasing interest in the wake of the Covid-19 pandemic. There is growing evidence that a healthy microbiome, the body’s community of microorganisms, can boost immune function. One paper in the International Journal of Environmental Research and Public Health suggests that a healthy microbiome supports the body’s natural defences and heightens immunity. Prebiotics provide food for the beneficial bacteria in the gut, and so may boost immune function.

High immunity is linked with low levels of inflammation. One review found there is promising evidence that prebiotics can reduce inflammation. These findings may be because prebiotics maintain the integrity of the gut wall which acts as a barrier to harmful molecules.

7. May reduce risk of chronic conditions

“The food sources of prebiotics have been associated with the reduction of most chronic diseases including heart disease, diabetes, cancer, and obesity,” says Petitpain.

Scientists don’t fully understand the mechanism, but prebiotics may increase the diversity of gut bacteria which is linked with reduced inflammation, which in turn reduces the risk of chronic conditions.

8. May influence mood

Ever wondered what the connection is between prebiotics and your brain? Scientists are exploring the concept of the gut-brain axis, with your gut health influencing your brain. Emerging research links diverse bacteria in the gut with reduced symptoms of depression. While there's no proof that they improve mental health, increased diversity of gut flora is one of the benefits of prebiotics. The impact on our mood is a compelling area for further investigation.

Verdict

So, the benefits of prebiotics include increased diversity of gut bacteria, which is beneficial for our overall health. But as research on prebiotics is still emerging, scientists are untangling cause and effect.

“Because prebiotics are found in high fiber foods and high fiber foods confer many benefits — including blood sugar control, the lowering of ‘bad’ cholesterol and promoting satiety — it is easy to say prebiotics play a role,” explains Petitpain.

What does this mean practically? “Until the science goes deeper and can tell us more about what role prebiotics play and how much of an impact they have, the best thing to do is include lots of high fiber foods in your diet.”