Scientists from Maastricht University and Keller Consulting Group reported that the combination of Reishi (Ganoderma lucidum), maitake (Grifola frondosa), and oyster (Pleurotus ostreatus) mushrooms may be considered a potential prebiotic, defined by Gibson et al as “a selectively fermented ingredient that results in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon host health”.
“To our knowledge whole mushrooms, let alone blends of different mushrooms, have not been tested frequently. Rather purified fractions, mostly the polysaccharide fraction, have been investigated,” explained the researchers in the journal Beneficial Microbes.
“In our experiments, in a validated in vitro model of the proximal colon, that closely mimics physiological conditions in humans, and which has been used for three decades in research on gut microbiology, we show that the blend of G. lucidum, G. frondosa and P. ostreatus has a beneficial effect on gut microbiota composition and activity.”
Consumer interest in mushrooms has been increasingly steadily over the past decade. Demand for mushroom-based products has been increasing with data from the American Botanical Council’s Herb Market report showing that, in the natural channel, 20% of the 20 ingredients with sales increases last year were mushrooms.
One supplier of mushroom extracts, Nammex, has reported surging demand for its products. Speaking to NutraIngredients-USA earlier this year, Jeff Chilton, Nammex CEO, said: “In the last two years, our sales have grown 80% each year. This sort of started back in 2015, 2016 when mushrooms really caught on and people caught up to what I consider to be a wonderful food and a great supplement. In the last four years, everything has skyrocketed.”
The list of benefits associated with mushroom products include immune support and cognitive function, with products also making energy and mood support claims. The new study, which used a proprietary blend of the three mushrooms provided by Nevada-based Aloha Medicinals, indicates that “prebiotic” could be added to this list.
The new study used TIM-2, a computer-controlled in vitro model of the colon, to assess the effects of the three mushroom blend on a pooled microbiota of healthy adults. Three doses of the predigested mushroom blend were investigated: 0.5, 1.0 and 1.5 g/day.
“The amount of extract used would equal 5-15 gram of fresh mushrooms (taking on average a water-content of 90%),” explained the researchers. “Given that the model is roughly scaled to the in vivo situation, one would expect 5-15 g of mushroom ingestion to have the same effect in vivo.”
The results showed a dose dependent increase in a number of butyrate producing bacteria, including Lachnospiraceae UCG-004, Lachnoclostridium, Ruminococcaceae UCG-002 and Ruminococcaceae NK4A214, and butyrate levels also increased in a dose dependent manner.
The data indicated that the proportion of all short chain fatty acids (SCFAs) comprised of butyrate for the high dose was almost twice (53%) that of the control (no mushroom medium) test (27%).
The potential prebiotic activity of the mushrooms was attributed to the variety of high-molecular-weight polysaccharides they contain.
“As butyrate is considered to be one of the microbial metabolites that contributes to health, by increasing barrier function and modulating inflammation, it would be good to reproduce these results in a clinical trial,” concluded the researchers.
Source: Beneficial Microbes
Published online ahead of print, doi: 10.3920/BM2021.0015
“A blend of 3 mushrooms dose-dependently increases butyrate production by the gut microbiota”
Authors: J. Verhoeven et al.