There is no consensus definition of gut health, but the term generally refers to the health or disease of the gastrointestinal (GI) tract; the diversity, composition, and function of the gut microbiome; and the ways in which these factors may influence nutrient absorption, GI distress, and other diseases or disorders.

Long-term dietary patterns shape the gut microbiome. Gut microbes produce energy by fermenting microbe-accessible carbohydrates, which are found in most fruits, vegetables, whole grains, nuts, seeds, and beans. Diets rich in these types of foods are associated with high levels of gut microbiome diversity and a lower risk of colorectal cancer. Short-term dietary changes can also change the composition of the gut microbiome, and in some cases, elimination diets are used to reduce the symptoms of certain digestive disorders.

Probiotics are some of the most widely studied supplements for gut health. They reduce some of the digestive symptoms associated with antibiotics, food borne illness, IBS, and IBD. Peppermint oil has also been shown to reduce IBS-associated abdominal pain in a number of studies. The evidence for other supplements, including digestive enzymes, collagen, and glutamine, is less compelling.