Mushrooms have been used both as food and as medicine in many cultures, and their popularity as both is growing in the United States. We have shown that they are inherently, or can easily be made to be, excellent dietary sources of 4 important bioactive compounds that are all known to decease in humans as they age. These are the micronutrients selenium and vitamin D2 and antioxidants glutathione and ergothioneine (Ergo). All of these except for Ergo can be found in significant amounts in other foods; hence, it will be the primary focus of this review. Because Ergo is made in nature primarily by nonyeast fungi, mushrooms are by far the best human dietary source. Humans produce a highly specific transport protein for Ergo that makes it highly bioavailable and avidly retained, leading many to speculate about its potential importance to human health because such specific transporters are rarely present for nonnutrient bioactive compounds. Ergo is found in small amounts throughout the food chain presumably owing to fungi in the soil passing it on to plants and then animals that eat them. We have preliminary evidence that Ergo levels in the American food supply might be compromised because of reduced fungal populations in agricultural soils caused by some cultivation practices. Relationships observed between estimated Ergo consumption and average longevity and reductions in chronic neurodegenerative diseases across different countries supports additional interest in Ergo as a dietary chemopreventive agent for aging-related diseases.
Robert B. Beelman, PhD, is professor emeritus in the Department of Food Science and director of the Center for Plant and Mushroom Foods for Health at the Pennsylvania State University College of Agricultural Sciences. He had made numerous important research contributions on the nutritional and medicinal properties of mushrooms; dietary antioxidants, including selenium and ergothioneine; and vitamin D enrichment of mushrooms.
Michael D. Kalaras, PhD, is a postdoctoral scholar in the Department of Food Science at the Pennsylvania State University College of Agricultural Sciences. His research focuses on nutritional properties of mushrooms, including ergothioneine and vitamin D.
John P. Richie, Jr, PhD, is professor of public health sciences and pharmacology at the Pennsylvania State University College of Medicine. For more than 30 years, he has conducted interdisciplinary studies on the role of oxidative stress and oxidant exposure on biological mechanisms involved in aging and cancer. An important focus of this research has been on the major cellular antioxidant and redox signaling agent, glutathione, and its role in health maintenance and disease prevention.
The authors have no conflicts of interest to disclose.
Correspondence: Robert B. Beelman, PhD, 404 Rodney A. Erickson Food Science Building, University Park, PA 16802 (firstname.lastname@example.org)