Scientists have identified 5 of the healthiest foods for your gut — and some are probably already in your kitchen

• Prebiotics are a special type of plant fiber which supports healthy digestion and metabolism.
• Good sources of prebiotics include garlic, onions, leeks, and bran cereal, a new study suggests.

You should be eating more prebiotic foods for better digestion, blood sugar control, and nutrient absorption, scientists say – and some of the best options may already be on your grocery list.

Prebiotics are a special type of plant fiber: carbohydrates that our bodies can't digest, but which feed colonies of beneficial bacteria that live in the gut. While overall dietary fiber is important for health, prebiotics are especially good at helping friendly gut microbes to thrive.

Researchers from San José State University analyzed data on the nutrient content for more than 8,000 different foods to see which were the best sources of prebiotics. Their results were presented at the 2023 annual meeting of the American Society for Nutrition held July 22–25 in Boston.

They found that about a third of the foods they studied contained some prebiotics. Foods with the highest concentration of prebiotics are dandelion greens, Jerusalem artichokes (root veggies also known as sunchokes,) leeks, garlic, and onions, providing between 100-240 milligrams of prebiotics per gram of food.

Other good sources of prebiotics in the study were bran cereal, asparagus, and black eyed peas (also called cowpeas), offering about 50-60 milligrams per gram.

Finding common ingredients with a prebiotic boost could help people improve gut health by eating more of foods they're already familiar with, according to Cassandra Boyd, presenting author of the study and a master's student at San José State University.

"Eating in a way to promote microbiome wellness while eating more fiber may be more attainable and accessible than you think," Boyd said in a press release.

The USDA dietary guidelines recommend about eating about 14 grams of fiber per day for every 1,000 calories you consume, but don't suggest a specific amount of prebiotics for optimal health.

The current advice from scientists who specialize in the microbiome is to aim for about 5 grams of prebiotics per day — you'd need to eat the equivalent of about half a small onion each day, according to the researchers.

Don't start chomping on raw onions or garlic just yet, though. The study also found that common prepared versions of these foods, like onion rings, are also a good source of prebiotics.

The gut microbiome is crucial for healthy digestion, metabolism, and overall wellbeing

Getting more pre- and probiotics in your diet can help keep the bacteria in your gut balanced and healthy, which can reduce the risk of serious illnesses like bowel cancer.

Eating for a healthy gut can also help you have better digestion and more steady energy throughout the day, thanks to stable blood sugar, dietitians previously told Insider.

Healthy microbes may also be useful for weight management, with evidence suggesting certain bacteria in the gut are linked to lower risk of obesity and related complications.

There's even some evidence that the gut microbiome plays an important role in mental health, and could someday play a role in helping treat conditions like depression and anxiety.