Greater incidences of physical and psychological stress have made fatigue a widespread problem in many countries, affecting productivity, health and the quality of life, and rendering even anti-fatigue therapies and pharmacological drugs less effective.
For this purpose, mushrooms are a potential solution. Their numerous bioactive constituents, including dietary fibre, minerals, vitamins, polysaccharides and proteins, make them popular for use in health foods.
Previous studies have found both edible and medicinal mushrooms to possess anti-fatigue properties, and researchers from Hong Kong Polytechnic University and South China University of Technology set out to review the major findings from these studies.
They found that there was a possibility that mushrooms "mitigate human fatigue through effects on the functional systems, including the muscular, cardiovascular, hormone, and immune system" through bioactive constituents such as nucleosides, peptides, phenolic compounds, polysaccharides and triterpenoids.
In terms of muscular function, mushrooms were found to improve liver and muscle glycogen storage and blood lactic acid, the major causes of muscular fatigue.
In terms of the hormone and immune systems, mushrooms stimulated testosterone, immune cell activity and cytokine expression.
Less stress, more energy
Mushrooms were also shown to reduce oxidative stress in cells through their free radical-scavenging ability, thereby improving energy metabolism in mitochondria and accelerating the rate of energy production.
Researchers observed that mushrooms were able to "stimulate the activities of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase, and catalase, to prevent oxidative stress and fatigue".
Furthermore, polysaccharides from the mushroom species T. fuciformis were found to stimulate the formation and activity SOD and GSH-Px.
The former is can neutralise superoxide radicals, and the latter can scavenge and inactivate hydroxyl radicals. These activities "protect tissues from exercise-induced oxidative damage, thus reducing physical fatigue".
Much room to explore
The review stated that in addition to the aforementioned anti-fatigue effects, mushrooms also enhance blood circulation, blood glucose regulation, and liver energy state and function.
However, since most of the studies reviewed were conducted on animals, the effects of mushrooms on human fatigue remain inconclusive.
As such, the researchers concluded that more research is necessary to "identify the active ingredients and to investigate their mechanism of action on the anti-fatigue effects", and that "more human trials should be performed to verify the anti-fatigue function of edible and medicinal mushrooms".
Source: Hindawi BioMed Research International
"Antifatigue Functions and Mechanisms of Edible and Medicinal Mushrooms"
Authors: Ping Geng, et al.