Eating more of these foods could benefit our gut microbiome, according to a presentation by researchers at the American Society for Nutrition
There is growing evidence that consuming prebiotics, certain types of fiber often found in plants that stimulate beneficial bacteria in the gut, can help support a healthy gut microbiome. However, we think that to obtain these nutrients we must consume exotic fermented foods, when in fact many foods that contain them are within our reach.
In a new study, scientists calculated the prebiotic content of thousands of different foods using existing literature to find out which foods offer the highest prebiotic content.
According to the study, the foods richest in prebiotics are five:
- dandelion leaves
- Jerusalem artichoke, also called Jerusalem artichoke
In addition to supporting the intestinal microbiota, foods rich in prebiotics contain large amounts of fiber, something that most people do not consume in sufficient quantity. According to Cassandra Boyd, who conducted the research with Associate Professor John Gieng, “Previous research has shown that eating foods rich in prebiotics is beneficial to health.” “Eating in a way that promotes microbiome wellness while consuming more fiber may be more achievable and accessible than you might think.”
Boyd will present his findings at NUTRITION 2023, the flagship annual meeting of the American Society for Nutrition, taking place July 22-25 in Boston.
Prebiotics and probiotics
Prebiotics, which can be considered microbiome foods, are different from probiotics, which contain live microorganisms. Both can benefit the health of the microbiome, but they work in different ways.
Studies have linked higher consumption of prebiotics with better blood glucose regulation, better absorption of minerals like calcium, and markers of better digestive and immune function. Although most dietary guidelines do not currently specify a recommended daily allowance for prebiotics, the International Scientific Association for Probiotics and Prebiotics, a non-profit scientific organization that established the current definition of prebiotics, recommends an intake of 5 grams per day.
For the study, the researchers used previously published scientific results to analyze the prebiotic content of 8,690 foods listed in the Food and Nutrient Database for Dietary Studies, a resource many scientists use to study nutrition and health.
About 37% of the foods in the database were found to contain prebiotics. Dandelion greens, Jerusalem artichokes, garlic, leeks and onions contained the highest amounts, between 100 and 240 milligrams of prebiotics per gram of food (mg/g). Other prebiotic-rich foods included onion rings, creamed onion, peas, asparagus, and Kellogg’s All-Bran cereal, each containing around 50-60 mg/g.
“Findings from our preliminary review of the literature suggest that onions and related foods contain multiple forms of prebiotics, leading to higher total prebiotic content,” Boyd said. “Multiple forms of onions and related foods appear in a variety of dishes both as flavorings and as main ingredients. These foods are commonly eaten by Americans and therefore would be a feasible target for people to increase their intake of prebiotics.”
Based on the team’s conclusions, Boyd says a person would need to consume about half a small onion a day to get 5 grams of prebiotics. Foods that contain wheat are at the bottom of the list. Foods with little or no prebiotic content are dairy products, eggs, oils, and meats.
The researchers hope the study will serve as a foundation to help other scientists assess the health implications of prebiotics and inform future dietary guidelines. They noted that more research is needed to understand how cooking influences prebiotic content and to better evaluate multi-ingredient foods.