Adverse reactions to common wild mushrooms

Denis R Benjamin Even Texas, for goodness sake. cases of adverse effects reported from To be fair, the questionnaire was western North America, suggesting hen Mushrooms: Poisons imperfect, suffering all the problems of a that L. conifericola (on conifers) is more and Panaceas was released retrospective study, including acquisition problematic than L. sulphureus, an (Benjamin, 1995), we bias and self-reporting. Even so, there eastern species. Western mycophagists celebrated by inviting friends for a W was enough useful information worth might have gotten the message, as in foraged meal. I provided the mushrooms sharing. Another disclaimer. Why is the latest survey the majority of the and the wild edible greens; another Benjamin such a killjoy? A curmudgeon adverse reports were from the East or couple dove in Puget Sound for rock indeed. Everyone else sees the magic in Midwest. There may be other reasons scallops, octopus and other delectables; mushrooms. He sees the dark side. For for this as well. Western mycophagists a hunter in the group donated pheasant forty years he was paid to be a pessimist. have access to a more abundant selection and one couple scoured their wine cellar Pathologists focus on finding problems of edible mushrooms, and few would for their best vintages. Each couple also and that is where he honed his skills. But take up basket space with a sour, woody, invited friends who had never attended let’s begin on a very positive note. Nearly and rather bland L. conifericola. Their one of our repasts. Fourteen of us sat eighty percent of all mycophagists have midwestern and eastern brethren on the around the table. The second course was happily consumed a wide variety of wild other hand, while having a great diversity a chanterelle soup served in those cute mushrooms with nary a problem. That’s of edible mushrooms, seldom find them little pumpkins usually available around quite remarkable considering the high in huge quantities, so COW tipping is a Halloween. Sometime during the fourth percentage of the general public who particular hobby. And the eastern species course, one of the guests began turning claim some form of food related disorder. might even be worth eating, although a cadaverous olive green. He excused Perhaps we are an especially hearty and there is great variation in peoples’ himself from the table and seconds resilient bunch. Perhaps some of Charles declarations of edibility—some claiming later we were all reminded of those McIllvaine rubbed off on us. it to be really delicious, while others find sounds from the driveway common after From the data we are able to draw a it tasteless. Most symptoms involve the fraternity parties. He returned looking few generalizations. Precise numbers GI tract and are the usual suspects of better, apologized, wiped the sweat off his for the incidence of adverse reactions is bloating, cramps, nausea, vomiting, and forehead and announced, “I had this same not possible as we do not have a reliable diarrhea. There are scattered reports of reaction to chanterelles many years ago, denominator—the number of people more disturbing symptoms such as facial but I thought that I had outgrown it.” All I who regularly eat a particular mushroom. swelling, incoordination, paresthesias envisaged was the headline in the morning Instead the results are grouped into three and extreme lethargy. Common reasons newspaper announcing “Mushroom broad categories—relatively common (up blamed for these unfortunate reactions Expert Poisons Dinner Guest.” to 15 % of individuals have some trouble); include undercooking, the host tree Mycophagists have a little secret. uncommon—more than 1%, and thirdly (e.g. L. gilbertsonii on eucalyptus or L. At least one in five of us has suffered the rare—generally a single case or a huroniensis growing on conifers), the following a meal of wild mushrooms. couple of reports. Before announcing season, or the habitat. How do we know this? We asked. The the winners, or losers as it were, I can Honey mushrooms (Armillaria spp.) first survey was done in the 1970s, already hear the outcry from those who are similar to COWs in the number of initially by the Mycological Society of love a particular indicted species, only to adverse reactions, and similar reasons are San Francisco and then by the Puget discover that not everyone is enamored given, of which undercooking is the most Sound Mycological Society, two of the of its virtues. But such is life. frequent. It appears to be more common largest groups on the West Coast. The in the West where A. solidipes (=ostoyae) results were consistent. The toxicology The culprits is the usual table fare, while A. mellea or committee of NAMA noted many The mushrooms producing the most A. tabescens (the latter now in the genus reports of adverse reactions to wild adverse effects are chicken-of-the-woods Desarmillaria) in the East less frequently “edible” mushrooms over the next (COWs), honey mushrooms, and parasols. cause issues. GI symptoms dominate four decades. Most reports appeared The first two are difficult to evaluate the clinical picture, but hallucinations reliable—not the result of some with precision, as there are a number are reported in few cases. Parasols misidentification or an overindulgence of different taxa in what mycophagists (Chlorophyllum rachodes, C. brunneum, of wine. Foraging has burgeoned in blithely label as COWs or honeys. and Macrolepiota “procera”) can produce the new century, so the survey was Opinions vary about the edibility similar GI upsets. The symptoms can repeated between 2013 and 2015, this of chicken-of-the-woods (Laetiporus be considerably more severe. It is not time country-wide, with questionnaires sulphureus, L. cincinnatus, and L. known how much of this is due to received from over 500 mycophagists. conifericola). There used to be more misidentification with C. molybdites, but 14 FUNGI Volume 10:3 Fall 2017 it is well described from regions where (Ichikawa, 2006). Similar anaphylactic NAMA. In this way we all learn. All the latter does not occur. reactions have followed enoki mycophagists are encouraged to review Leccinum spp. deserve special mention, (Flammulina velutipes) (Otsuji, 2015) the extensive and well done reports as there are reports from some regions, as well as a couple of deaths following L. that Dr. Beug has routinely published in Colorado being the most noteworthy, sulphureus and L. conifericola. Each of us McIlvainea over the years. Chances are where a substantial fraction of scaber is genetically distinct, as well as having high that you will find a report on the eaters experience GI symptoms which personalized microbiomes, all of which mushroom that made you ill last night. may last for a number of days. Whether determines how we digest, metabolize this is due to differences in species, and react to a given mushroom. When References habitat or availability is still unclear. no clear allergic mechanism is involved Benjamin, D.R. 2015. Neurological The next group produces symptoms physicians use jargon words like effects of Morchella sp. FUNGI 8(3): in a small minority of people (1-5%), but “idiosyncratic,” which is a fancy way of 24-25. they include many of the most commonly saying that we don’t know. Benjamin, D.R. 1995. Mushrooms: eaten wild mushrooms. Because of this There may also be relationship in a few Poisons and Panaceas. W.H. Freeman the NAMA registry has accumulated individuals between the combination of and Co., New York, NY. numerous reports over the years. In this alcohol and a wild mushroom meal. This Beug, M.W., M. Shaw, and K.W. group morels stand out, with chanterelles is not confined to the classic Coprinopsis Cochran. 2006. Thirty-plus years of and boletes distant contenders. An atramentarius (“tippler’s bane” inky mushroom poisoning: summary of article in FUNGI last year documented cap), but has been reported with morels, the approximately 2,000 reports in the neurological issues with morels boletes and oyster mushrooms, among the NAMA case registry. McIlvainea (Benjamin, 2016). To paraphrase Dr. others. The cause of this association, 16(2): 47-68. Beug, in his annual review of mushroom if real and not pure coincidence, is Beug, M.W. 2016. Mushroom poisoning poisonings in McIlvainea “that if morels unknown. There are some individuals in North America. McIlvainea 25: 1-8. were not so delicious, they could have who are convinced that they are fine Ichikawa, K., R. Ito, Y. Kobayashi, been labelled as toxic” (Beug, 2016). In when they avoid alcohol. Should you be M. Aihara, H. Osuna, and Y. Aihara. fact, in the extensive NAMA review, one of these unfortunates, abstinence is 2006. A pediatric case of anaphylaxis morels accounted for over 3% of all the the simple solution. caused by matsutake mushroom documented adverse effects. As an aside, and a topic for future study (Tricholoma matsutake) ingestion. The final group includes just about and publication, was the observation Allergology International every mushroom that anyone has that a substantial number of professional 55(1): 85-88. attempted to eat. Some of these mycologists do not eat wild mushrooms at Otsuji, K., K. Ohara, M. Nakamura, reactions are not trivial as noted by all, or at best only a few selected species. R. Amazumi, C. Higa, K. Kakazu, and one unfortunate after a meal of lion’s What do they know that we don’t? Y. Kondo. 2015. A case of anaphylaxis mane (Hericium erinaceus): “spent the Amateur mycophagists continue the caused by enokitake (Flammulina entire weekend in the bathroom.” Even long tradition of being willing human velutipes) ingestion. Japanese Journal the usually bland and benign puffballs “guinea pigs,” slowly discovering what of Allergology 64(1): 63-67. [Article (Calvatia, Lycoperdon, etc.) have is safe to eat. We do it without formal in Japanese] produced unexpected symptoms. protocols or approval by Institutional A striking finding in reviewing the Review Boards, things that are normally Denis Benjamin is author of results of the questionnaires and all the required for any human experimentation. Mushrooms: Poisons and Panaceas, NAMA reports for the past 50 years is We should share any adverse reactions past-chair of the NAMA Toxicology the number of people who still insist by reporting them to organizations like committee, and a watercolorist. on eating raw mushrooms or who barely cook them. This habit is clearly responsible for some of the adverse affects ascribed to morels, COWs, leccinums, boletes, shiitake, and others. The other “perversion” is the mixed stew, in which the participants feel compelled to dump the entire day’s find into the same pot. Not only is this a culinary nightmare, but it complicates the toxicologist’s ability to sort out the culprits following a miserable outcome. The pathophysiology of these adverse effects is entirely unknown. Most do not appear to be classic allergic reactions, although clearly some are. There is a report of a young girl dying from an anaphylactic reaction to matsutake FUNGI Volume 10:3 Fall 2017 15