Prebiotics: What They Are, What They Do, and Where You Can Find Them

But have you heard of prebiotics? According to the official definition, a prebiotic is any substance used by microorganisms inside the body that confers health benefits. Translation: prebiotics are beneficial microbes’ food. While researchers are still learning about their full potential to boost overall health or even treat disease, one thing is for certain—adding more prebiotics to your diet can give you a happier gut.

How prebiotics work

Most prebiotics are types of dietary fiber, which is a kind of carbohydrate that human enzymes can’t digest. Not every fiber is a prebiotic, however, because there are two categories of dietary fiber: soluble fiber, which is fermented by gut bacteria, and insoluble fiber, which is not fermented. The soluble fibers that are metabolized by beneficial gut microbes are considered prebiotics. Inside your gut, prebiotics stimulate beneficial gut microbes to grow, improving gut health—and other areas of health, too.

Some prebiotics come from sources besides food and impact parts of the body beyond the gastrointestinal tract, but most of the ones we know about are found in food.

Which foods contain prebiotics?

Plants like Jerusalem artichoke, chicory root, apples, bananas, asparagus, onions, leeks, and garlic contain small amounts of prebiotics; and some yogurts, cereals, and breads contain prebiotic additives, like galacto-oligosaccharides (GOS), fructo-oligosaccharides (FOS), and inulin.

While it’s no longer on the menu for us adults, breast milk contains oligosaccharides, a prebiotic that has been found to increase the population of healthy bifidobacteria and discourage the growth of pathogens in babies’ guts. In fact, several types of infant formula are now supplemented with oligosaccharide prebiotics.

What are the major health benefits of prebiotics?

The health effects of prebiotics include improved gastrointestinal health (inhibition of pathogens and immune system stimulation), reduced blood lipid levels, and improved brain function.

Recent research has found that prebiotics may help prevent and treat Type 2 diabetes and cardiovascular disease, lower cholesterol, and positively impact metabolism. Researchers have also found that a healthy gut microbiome fed by prebiotics has positive effects on bone density and strength.

A 2017 study published in the American Journal of Clinical Nutrition found that children who tried prebiotics felt more satisfied after a meal, which could help children with obesity regulate their appetites. A 2017 study at the University of Colorado published in Frontiers in Behavioral Neuroscience was the first research to demonstrate that a prebiotic diet provides protection from stress and positively impacts sleep.

Prebiotics represent an exciting new area of scientific research, and many organizations are funding projects to study how they work, what they can do, and how they might be used to prevent or treat disease.

What do we still need to learn about prebiotics?

The National Institutes of Health (NIH) is funding new research on prebiotics that may include investigations into how prebiotics could be used to help manage inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), or other conditions. Other organizations are funding research on new microbiome-based therapies, methods for analyzing the effects of prebiotics on gastrointestinal tract microbiota, and microbiome-based strategies for the prevention of lifestyle-related chronic diseases.

How can I use prebiotics to improve my health?

Fruits, vegetables, and whole grains contain prebiotics, so your healthcare provider’s usual advice about including a variety of fruits, veggies, and grains in your diet is certainly sound. Eating plenty of fiber-rich foods will also help you take in prebiotics, as well as vitamins and minerals. If you’re following the dietary guidelines for fiber intake, you’d want to eat 25 grams of fiber for every 2,000 calories you consume each day. The bonus is that by eating healthy, plant-based, fiber-rich foods, you’ll gain other health benefits, too.