Edible mushrooms are a food item either loved or despised for their flavor and texture. Certainly these fungi can’t boast of being the most attractive food on earth, but the hidden beauty of edible mushrooms is revealed when we take a peek at their nutritional benefits. It is here that mushrooms can boast.
A bird’s eye view will show that mushrooms possess high amounts of functional proteins, low total fat level, a high proportion of polyunsaturated fatty acids (PUFA), and nutritionally significant content of vitamins (B1, B2, B12, C, D, and E). Further, mushrooms have a low glycemic index and sodium concentration, while supplying a good amount of potassium and phosphorus.
Mushrooms possess powerful antioxidant properties that promise to aid in our fight against oxidative stress and the chronic health conditions that spring forth from this damaging state. Phenolics, flavonoids, glycosides, polysaccharides, tocopherols, ergothioneine, carotenoids, and ascorbic acid are among the most common antioxidant compounds found in both wild and cultivated mushrooms. These antioxidant compounds protect against oxidation at several levels and through various mechanisms, including scavenging free radicals, deactivating toxic heavy metals, inhibiting lipid hydroperoxides, and regeneration of primary antioxidants. Further, mushroom antioxidant compounds have been shown to induce cell signals and change gene expression, resulting in activation of endogenous enzyme systems.
Mushrooms are also rich sources of antioxidant vitamins. The ascorbic acid content of certain species of wild edible mushrooms was found to be higher (100 mg/100 g dry weight of ascorbic acid in the methanolic extract of the wild edible mushroom Cantharellus cibarius) than in some fruits and vegetables, commonly recommended for their vitamin C content. For example, strawberries are reported to carry 60 mg/100 g of ascorbic acid and citrus fruits, 30–50 mg/100 g. Other studies found even higher amounts of ascorbic acid, averaging of 150–300 mg/kg dry matter of mushroom. Vitamin E (including tocopherols and tocotrienols) is found in mushrooms, as well as several potent carotenoids including β-carotene, lutein, and canthaxanthin, the antioxidant pigment responsible for making salmon look pink.
The epidemic prevalence of vitamin D deficiency has caused several practitioners to amp up their recommendations to consume vitamin D rich foods, but rarely do mushrooms make the list. Although mushrooms may not have the highest source of vitamin D, they will certainly contribute to an individual’s overall intake. The three most commonly consumed mushrooms –the button mushroom (Agaricus bisporus), oyster mushrooms (Pleurotus species), and shiitake mushrooms (Lentinula edodes) – have high concentrations of ergosterol (vitamin D2) which help to strengthen cell membranes, modulate membrane fluidity, and assist in intracellular transport. They also supply lesser amounts of vitamin D3 and D4. The vitamin D content of mushrooms is directly related to its exposure to sunlight; therefore, retail mushrooms grown in atmospherically controlled growing rooms may only possess negligible amounts of vitamin D, but wild harvested mushrooms can contain amounts in excess of 10 μg/100 g fresh weight (about 3 mushrooms).
Mushrooms may not come to mind as a gut-friendly food, but they are ranked among the best foods for promoting a healthy microbiome. Mushrooms are a rich source of various prebiotic fibers including chitin, hemicellulose, β and α-glucans, mannans, xylans, and galactans. The prebiotics not only help to mitigate pathogenic organisms in the gut, but also stimulates the growth of beneficial microbiota. One particular prebiotic fiber found in mushrooms, β glucans, also build immunity to help modulate inflammation and optimize the gut environment. For instance, reishi, an edible medicinal mushroom, is known for its ability to promote immunity. Its rich supply of polysaccharides (including β-d-glucan), terpenoids, and total phenols have given it the ability to increase the quantity of Bifidobacteria, lactobacillus, roseburia, and lachnospiraceae. The chaga mushroom is known for its polysaccharide content of 98.6 percent and for its capability of increasing Bacteroidetes and inducing other changes to encourage a healthy bacteria profile in the gut.
As a rich source of antioxidants, vitamin D, prebiotics, and several crucial vitamins and minerals, mushrooms should no longer be treated as a food option governed by preference, but rather a significant element of a health-promoting diet. These unadorned fungi truly reflect the meaning of “food is medicine.”