USDA-ARS Updates Mushroom Data

USDA's Agricultural Research Service (USDA-ARS) recently completed an analysis that will update average nutrient data for seven popular mushrooms: white button, oyster, shiitake, enoki, portobello, crimini and maitake. The research was coordinated by David Haytowitz, nutritionist, USDA-ARS Human Nutrition Research Center, Beltsville, MD.

USDA-ARS reported in a recent press release that the mushrooms analyzed during the course of this study were collected from "retail outlets around the country to get a nationally representative sampling." Each different mushroom variety was analyzed to determine average fat, fiber, protein and carbohydrate content, as well as levels of vitamins, minerals and ergosterol, a fungal sterol that acts as a precursor to vitamin D.

The mushrooms were mostly analyzed raw, although researchers did analyze white button mushrooms after stir-frying and microwaving to determine any compositional differences between their raw and cooked states. Likewise, researchers analyzed portobello mushrooms after grilling, and shiitake mushrooms after stir-frying. Results showed that the mushrooms completely retained most of their nutrients, while some nutrients dropped to 80% to 95% of their raw levels after cooking.

Researchers found that all of the mushrooms tested contained a significant amount of copper. In its report, USDA-ARS noted that "each cup of stir-fried white button mushrooms provides 0.3 mg of copper," which is about one-third of the RDI for adults. The mushrooms also were found to contain good levels of potassium. USDA-ARS notes that two-thirds of a cup of sliced, grilled portabella mushrooms contains the same level of potassium as a medium-sized banana.

The new nutrient values for mushrooms will appear at http://www.ars.usda.gov/nutrientdata/in the near future. This research was funded in part by the Mushroom Council, Dublin, CA (http://www.mushroomcouncil.org/).