Eating an avocado daily may significantly enhance gut health, according to recent research from the University of Illinois. Avocados, packed with dietary fiber and heart-healthy monounsaturated fats, have long been recognized for promoting satiety and lowering cholesterol—but their impact on gut microbes was previously unclear.
“We knew avocados help you feel full and reduce blood cholesterol, but we wanted to understand their effects on gut microbes and the metabolites they produce,” explains Sharon Thompson, a graduate student in Nutritional Sciences and lead author of the study.
The study revealed that participants consuming an avocado with one daily meal showed increased levels of fiber-degrading gut microbes and metabolites that support intestinal health. They also exhibited greater microbial diversity compared to the control group without avocados.
“Microbial metabolites are health-influencing compounds produced by gut bacteria,” Thompson notes. “Avocado intake lowered bile acids while raising short-chain fatty acids—changes linked to positive health outcomes.”
The 12-week trial involved 163 overweight or obese (BMI ≥ 25 kg/m²) but otherwise healthy adults aged 25-45. Participants replaced one meal daily with a study-provided option: avocado-inclusive for the intervention group, avocado-free for controls. They submitted blood, urine, and stool samples regularly, tracked meal adherence, and logged full diets every four weeks.
Unlike prior avocado studies focused on weight loss, this one allowed normal eating habits aside from the substituted meal, isolating avocado's gut effects.
“We aimed to test whether avocados' fats and fiber positively influence the gut microbiome and its ties to health markers,” says senior author Hannah Holscher, Assistant Professor of Nutrition in Food Science and Human Nutrition.
Though calorie-dense, avocados led to higher fecal fat excretion in the intervention group despite slightly higher intake. “This suggests reduced fat absorption, likely from lower bile acids—key for fat digestion. The avocado group had less stool bile acids and more fat,” Holscher elaborates.
Avocados' monounsaturated fats benefit both heart and microbiome. Their soluble fiber—10 grams per medium fruit—feeds beneficial bacteria, contributing substantially to the 28-34 grams daily recommendation.
“Dietary fiber is a win-win: we can't digest it, but our gut microbes thrive on it, producing health-promoting byproducts,” Holscher adds. Avocados also deliver under-consumed nutrients like potassium.
