Researchers from the University of California at San Jose in the United States identified five foods that lead the list when it comes to prebiotic content. The lineup includes dandelion greens, yams, garlic, leeks, and onions. The study results were shared at the 2023 Nutrition Congress organized by the International American Nutrition Society.
Prebiotics are a particular kind of fiber that the upper digestive tract does not digest or absorb. Instead, they travel to the large intestine where gut bacteria ferment them, stimulating the growth and activity of important microbial communities.
In practical terms, consuming these fibers can help stabilize blood sugar, improve mineral absorption, and support immune function and digestive health. The researchers aimed to map how much prebiotic content exists across a wide range of foods and how this might influence daily dietary choices.
During the study, the team assessed the prebiotic content of 8,690 foods by reviewing existing scientific literature. They found that roughly 37 percent of the foods in the database contain measurable prebiotic components. Of the items tested, dandelion greens, Jerusalem artichokes, garlic, leeks, and onions stood out with approximately 100–240 mg of prebiotics per gram of product. Other notable sources include onion rings, boiled onions, black-eyed peas, and asparagus, each containing about 50–60 mg per gram. These figures help consumers compare choices and tailor meals to support gut health. (Source: International American Nutrition Society Nutrition Congress 2023)
Further context ties prebiotic intake to long-term physiological effects, including how consistent eating patterns can influence circadian alignment and metabolic health. Ongoing research continues to explore these links, aiming to offer clearer guidance for daily nutrition strategies that support a balanced gut microbiome and overall well-being.