75% of Reishi supplements don’t actually contain Reishi mushroom, says USP analysis

By Stephen Daniells contact

- Last updated on GMT

Demand for medicinal mushrooms like Reishi has never been higher and the global market was pegged at $18 billion in 2014 (up from $6 billion in 1999). Image: © Getty Images / Songsak Paname
Demand for medicinal mushrooms like Reishi has never been higher and the global market was pegged at $18 billion in 2014 (up from $6 billion in 1999). Image: © Getty Images / Songsak Paname
Only five out of 19 supplement products labeled as Reishi mushroom purchased in the U.S. could be verified as genuine Reishi mushroom, says a new study that highlights quality issues in the category.

Using a “reliable and scientific toolkit”, scientists from the United States Pharmacopeial Convention (USP) and the University of Macau (China) found that most of the products that failed the tests lacked characteristic triterpenoids and also had a starch-like polysaccharide profile that was inconsistent with Reishi mushroom (Ganoderma lucidum​).

The researchers used highly accurate testing methods including HPTLC, Colorimetric method, GC-MS, and High Performance Size-exclusion Chromatography.

“[T]his study suggested the quality consistency of ​G. lucidum dietary supplements collected in USA was extremely poor, which should be carefully investigated,” ​wrote the researchers in Nature’s Scientific Reports​ journal.  

“The time has come for supplement companies to embrace the new analytical standards”

As reported earlier this year by NutraIngredients-USA,​ the booming mushroom category has issues arising from the difference between a mushroom (the ‘fruiting body’) and mycelium (the ‘vegetative body’). Commercial suppliers offer dried mushrooms, mycelium-on-grain products, and mushroom extracts.

Jeff Chilton, founder of Nammex Organic Mushroom Extracts and a leading voice for the quality and authenticity of mushroom products, told NutraIngredients-USA: “The time has come for supplement companies to embrace the new analytical standards and testing protocols that I have presented in my 2015 White Paper, Redefining Medicinal Mushrooms​.

“Now that USP has published their study with analytical data that supports my findings, there is no longer any excuse for companies to ignore this problem. Those who choose to carry on with business as usual will find themselves increasingly isolated in a marketplace that now requires increased transparency and higher quality standards based on scientific analysis.”

Chilton contributed to the USP study by submitting three Nammex Reishi mushroom extract samples, all of which passed USP’s testing standards, he said.

New study shows the range of analytical techniques that ought to be used

Anton Bzhelyansky, MS, scientific liaison at USP and co-author on the new paper, told NutraIngredients-USA that proper mushroom ingredients and products analysis is technically challenging and requires advanced methodologies. “Adequate characterization of mushroom extracts should rely on a suite of techniques targeting complex carbohydrates; in the absence of those, it may be difficult to detect substitution and adulteration,”​ he said.   

“Considering that starchy matrices are frequently used as substrates for mushroom cultivation, as well as carriers in the manufacture of extracts, analytical methodologies need to be developed that permit reliable differentiation between the mushroom-derived carbohydrates and those of extraneous nature, as well as the qualitative and quantitative assessment of the former."​ 

Bzhelyansky continued: “The experiments undertaken by the USP Visiting Scientist, Prof. Shaoping Li [who spent just over two months at USP early in 2015] offer a glimpse at not just the quality of commercial mushroom products available to the US consumers, but also the range of analytical techniques that ought to be assessed for proper quality analytics." 

“It would be disappointing to see the interest in medicinal mushrooms disappear because of quality issues with the products on the market”

USP Monographs

USP's Bzhelyansky explains: “USP developed dietary supplement monographs for ​G. lucidum Fruiting Body and ​G. lucidum Fruiting Body Powder. 

“USP does not have a monograph for ​G. lucidum Fruiting Body Dry Extract.  However, USP Herbal Medicines Compendium has the G. lucidum Fruiting Body Dry Extract monograph besides the monographs for the ​G. lucidum Fruiting Body and ​G. lucidum Fruiting Body Powder.”

Commenting on the study's findings, Stefan Gafner, PhD, Chief Science Officer at the American Botanical Council, told NutraIngredients-USA: “Overall, this is a thorough chemical analysis of the 19 reishi supplements. Looking at the samples, the authors have analyzed 6 samples of powdered fruiting body, one sample of fruiting body with added polysaccharides, 11 various extracts, and one sample of mycelium. The fact that only 26.3% of the tested products were found to be authentic suggests a need for improved quality control measures. While it is acknowledged that the sample size in this study is limited, the samples seem to be fairly representative of the US market according to the authors.

“There are a number of factors that complicate the authentication of reishi products, in particular the extracts. Several species of ​Ganoderma can be sold as reishi according to the second edition of the American Herbal Product’s Association’s Herbs of Commerce. These include ​G. lucidum, G. japonicum, and ​G. tsugae. Chemically, the fruiting bodies of ​Ganoderma species are comparatively similar, with polysaccharides, glycoproteins, proteins, and triterpenes as the main constituents.

Dr Gafner continued: “The composition of the mycelium polysaccharides varies depending on the medium in which they were cultivated, which complicates the chemical evaluation of commercial products. However, it seems that cultivation on starch-containing biomass is quite common. This could partially explain why starch was found in 13 of the 19 samples. It would have been interesting to add a few authentic mycelium samples to the investigation to determine if some of the products labeled as extracts were made from reishi mycelium. It leaves the question about what a good mycelium product should look like, and how much starch – if any – such products may contain, unanswered.

“I believe that one of the main issues is that some of these reishi products may be made of mycelium. But since marketed products often show an image of the fruiting body, this is what many consumers expect to be present in those reishi “mushroom” supplements.

“This points already to an important aspect of a quality mushroom product: it would be really helpful to have the source material (fruiting body versus mycelium) indicated on the label. It would be disappointing to see the interest in medicinal mushrooms, which has been steadily growing, disappear because of quality issues with the products on the market,” ​added Dr Gafner.

Labeling regulations and guidance

In 1976, the US Food and Drug Administration issued the following:​  “Mushroom mycelium grown in acceptable media is regarded as suitable for food use. Any food in which mushroom mycelium is used should be labeled to state that fact. Labeling should not suggest or imply that the food contains mushrooms.

“For example, a soup in which mushroom mycelium is an ingredient should not be labeled or sold as "mushroom soup" since that name by long consumer understanding and usage is preempted by soup containing real mushrooms.”

Earlier this year, the American Herbal Products Association addressed the issue and released a guidance​ for labeling products that contain fungi ingredients.

It should be noted that the products tested in the USP study were purchased in February or March 2015. Nammex’s Chilton says he has seen a change in the marketplace over the last two years. “More and more companies are specifically stating that their products do not contain mycelium or grain or starch,” ​he said. “This is especially true of newer and younger companies that are truly interested in finding the highest quality raw materials.

“Companies interested in medicinal mushrooms are now actually demanding the genuine mushrooms that have been used by Chinese herbalists for centuries.”

Source: Scientific Reports
7​, Article number: 7792 (2017), doi:10.1038/s41598-017-06336-3
“Evaluation on quality consistency of Ganoderma lucidum dietary supplements collected in the United States”
Authors: D-T. Wu, Y. Deng, L-X. Chen, J. Zhao, A. Bzhelyansky, S-P. Li

For more information about Professor Li's extensive work on carbohydrate analysis and authored several fundamental reviews, please click the following links: http://dx.doi.org/10.1002/jssc.201200874​ and http://dx.doi.org/10.1016/j.trac.2013.05.020​ .

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