Not only do mushrooms rank just behind meat in terms of protein, but their amino acid profile is also similar to that of meat, with all nine of the essential amino acids (per a 2017 article in the Journal of Microbiology, Biotechnology and Food Sciences). While portobello mushrooms aren’t a great source of carbs, the fiber in this fungus has chitin and beta-glucans that make them particularly healthy. Chitin is a type of fiber found on the wall of the mushroom that can regulate the immune system, according to a 2018 article in Clinical Reviews in Allergy & Immunology. Beta-glucans can also support the immune system and prevent cholesterol from food from being absorbed by your body (per WebMD).
Overall, mushrooms don’t have much fat, but they do have linoleic acid, which is an essential fatty acid. Per Harvard School of Public Health, linoleic acid can reduce cholesterol and blood pressure. Mushrooms are good sources of minerals, particularly potassium and phosphorus. You’ll also find vitamins such as niacin and riboflavin.