Mushrooms: Are Some Varieties Poisonous?

Mushrooms are a tasty and nutritious food source, but they can also be dangerous. Of the 100,000 species of mushrooms in the world, more than 100 are poisonous to humans. Eating poisonous wild mushrooms can result in symptoms ranging from mild gastrointestinal discomfort to organ failure and death. Poisonous mushrooms often closely resemble edible species, making them hard to identify. The most common toxin causing severe poisoning is amatoxin, found in various mushroom species, including the death cap, which is responsible for the majority of fatal mushroom poisonings. Other toxins include orellanine, psilocybin, and muscarine. To avoid the risk of poisoning, it is essential to source mushrooms from a reliable supplier or forage with a qualified expert.

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Poisonous mushrooms can cause hallucinations, delirium, seizures, and comas

While only about 100 of the vast number of mushroom species are toxic, poisoning can occur due to misidentification of a poisonous species as an edible one. Many poisonous mushrooms bear an unfortunate resemblance to edible species. For example, the death cap mushroom, perhaps the deadliest of all mushrooms, resembles edible straw mushrooms and Caesar's mushrooms. Amatoxin, the toxin found in death caps, blocks the replication of DNA, leading to cell death. This can affect cells that replicate frequently, such as those in the kidneys, liver, and central nervous system. Other mushrooms, such as the autumn skullcap, contain the same amatoxins as the death cap and can cause diarrhea, vomiting, hypothermia, and liver damage, and can result in death if left untreated.

Mushroom poisoning can also result in neurotoxic effects like hallucinations and agitation. While typically nonfatal, severe outcomes can include paranoid psychosis with visual and auditory hallucinations that can last for up to 5 days. The duration of symptoms varies from 8 to 24 hours, and recovery is typically complete within 24 hours. However, fatalities have been reported in severe cases.

Hallucinogenic mushrooms, also known as magic mushrooms, contain the hallucinogenic chemical psilocybin. Eating these mushrooms can lead to euphoria, hallucinations, and sensory distortion. Although psilocybin is not considered addictive, users may experience disturbing hallucinations, anxiety, panic, paranoia, and short-term psychosis. According to the National Institute on Drug Abuse, people can continue to experience flashbacks anywhere from weeks to years after using hallucinogenic mushrooms. This condition is called hallucinogen-persisting perception disorder and is rare.

In addition to hallucinations, delirium, and seizures, poisonous mushrooms can also cause gastrointestinal issues, including nausea, vomiting, abdominal cramps, and diarrhea. Some people may also experience muscle spasms, confusion, incoherent speech, dizziness, and involuntary twitching of the limbs. It is important to seek medical attention immediately if any of these symptoms occur after consuming mushrooms.

Amatoxin is the most common toxin that causes severe mushroom poisoning

Out of the thousands of mushroom species, only about 50 to 100 are toxic to humans. Among these toxic mushrooms, the most common toxin that causes severe mushroom poisoning is amatoxin, which is found in various mushroom species that cause the most fatalities every year. Amatoxins are a subgroup of at least nine related cyclic peptide toxins found in three genera of deadly poisonous mushrooms: Amanita, Galerina, and Lepiota. They are also found in one species of the genus Pholiotina.

Amanita, or "the death cap", is a type of mushroom named for its substantial amount of amatoxin, which has about 10 mg per mushroom, the lethal dose. Amatoxins block the replication of DNA, which leads to cell death. This can affect cells that replicate frequently, such as those in the kidneys, liver, and eventually, the central nervous system. They can also cause the loss of muscle contraction and liver failure. Despite the severe and dangerous symptoms, amatoxin poisoning is treatable if given quick, professional care.

Amatoxins are very potent, as little as half a mushroom cap can cause severe liver injury if swallowed. They have a similar structure of eight amino-acid residues arranged in a conserved macrobicyclic motif, with an overall pentacyclic structure when counting the rings inherent in the proline and tryptophan-derived residues. They were isolated in 1941 by Heinrich O. Wieland and Rudolf Hallermayer. All amatoxins are cyclic peptides that are synthesized as 35-amino-acid proproteins, from which the final eight amino acids are cleaved by a prolyl oligopeptidase.

Amanitin, a type of amatoxin, is very closely related to phalloidins, which are bicyclic 7-residue toxins. They are both part of the MSDIN protein family, named after the highly conserved 5-amino-acid sequence in the preproteins. Amanitins are potent and selective inhibitors of RNA polymerase II, a vital enzyme in the synthesis of messenger RNA (mRNA), microRNA, and small nuclear RNA (snRNA). Without mRNA, which is the template for protein synthesis, cell metabolism stops and apoptosis ensues.

Mushroom poisoning can cause liver and kidney failure, and even death

Out of the approximately 100,000 species of mushrooms in the world, more than 100 are poisonous to humans. While some wild mushrooms cause only mild symptoms like an upset stomach, others can lead to organ failure and death. Poisonous mushrooms can be mistaken for edible ones, sometimes with fatal effects.

The most common toxin that causes severe poisoning is amatoxin, which blocks the replication of DNA, leading to cell death. This toxin is found in various mushroom species that cause the most fatalities every year. Amatoxin is found in mushrooms such as the death cap (Amanita phalloides), which is responsible for the majority of fatal mushroom poisonings. Within 6 to 12 hours of consuming the death cap, violent abdominal pain, vomiting, and bloody diarrhoea appear, causing a rapid loss of fluid from the tissues and intense thirst. Signs of severe involvement of the liver, kidneys, and central nervous system soon follow, including a decrease in urinary output and a lowering of blood sugar. Other mushrooms that have a similar effect to the death cap include some species of Galerina, Lepiota, and Conocybe.

Conocybe filaris, an innocent-looking lawn mushroom that is especially common in the Pacific Northwest, is another example of a potentially fatal mushroom. It features the same mycotoxins as the death cap mushroom, and the onset of gastrointestinal symptoms typically occurs 6-24 hours after consumption, frequently leading to an initial misdiagnosis of food poisoning or the stomach flu. The patient may appear to recover, only to suffer from a life-threatening reappearance of gastrointestinal distress, coupled with liver and kidney failure.

Another toxin to be aware of is orellanine, which can cause kidney failure and death if left untreated. It may take 3-20 days for symptoms to appear, with kidney failure typically beginning around day 11 and becoming symptomatic by day 20. Species in the genus Cortinarius, such as the deadly webcap (Cortinarius rubellus) and the fool's webcap (Cortinarius orellanus), contain this toxin.

To avoid the risk of mushroom poisoning, it is essential to source mushrooms from a reliable supplier, such as a greengrocer or supermarket, or to forage with a qualified expert. If you suspect that you or someone you know has consumed a poisonous mushroom, seek medical attention immediately.

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Poisonous mushrooms are often mistaken for edible ones, sometimes with fatal effects

Of the approximately 100,000 species of mushrooms in the world, more than 100 species are poisonous to humans. Poisonous mushrooms can be mistaken for edible ones, sometimes with fatal consequences. For example, the death cap mushroom is responsible for the majority of fatal mushroom poisonings. This is because it closely resembles several edible and popularly eaten species, such as Caesar's mushroom. Amatoxins, the toxins found in death caps, are heat-stable and withstand cooking temperatures, quickly damaging cells throughout the body. Within 6 to 12 hours after consumption, violent abdominal pain, vomiting, and bloody diarrhoea appear, causing a rapid loss of fluid from the tissues and intense thirst. Signs of severe involvement of the liver, kidneys, and central nervous system soon follow, including a decrease in urinary output and a lowering of blood sugar.

Another example is the Conocybe filaris, an innocent-looking lawn mushroom that is especially common in the Pacific Northwest. It features the same mycotoxins as the death cap mushroom and is potentially fatal if eaten. The onset of gastrointestinal symptoms often occurs 6-24 hours after consumption, frequently leading to an initial misdiagnosis of food poisoning or the stomach flu. The patient may appear to recover, only to suffer from a life-threatening reappearance of gastrointestinal distress, coupled with liver and kidney failure.

The two species of webcap, the deadly webcap (Cortinarius rubellus) and the fool's webcap (Cortinarius orellanus), are very similar in appearance to each other and to several edible varieties. They contain orellanin, a poison that causes symptoms similar to the common flu. Orellanin has a long latency period and may take 2 days to 3 weeks to cause symptoms, often leading to a misdiagnosis. If left untreated, the toxin causes kidney failure and death. In 2008, English author Nicholas Evans mistakenly collected and served webcap mushrooms to his relatives, resulting in hospitalization and kidney transplants for four of them.

Autumn skullcap mushrooms (Galerina marginata) are sometimes mistaken for hallucinogenic mushrooms and are poisonous and potentially deadly if eaten. They are common throughout the Northern Hemisphere and parts of Australia and feature the same amatoxins as the death cap mushroom. Ingestion causes diarrhoea, vomiting, hypothermia, and liver damage, and can result in death if left untreated.

To avoid the health risks associated with poisonous mushrooms, it is essential to source mushrooms from a reliable supplier, such as a greengrocer or supermarket, or to forage with a qualified expert. There is no home test available to distinguish between edible and poisonous mushrooms, and mushroom identification apps and guidelines may not be accurate. If there is any concern that a poisonous mushroom has been ingested, it is recommended to seek immediate medical attention.

There is no home test to distinguish between poisonous and edible mushrooms

It is imperative to be able to accurately identify a mushroom before consuming it, as some poisonous mushrooms can be deadly. Poisonous mushrooms may closely resemble edible mushrooms, and there is no home test to distinguish between the two. Therefore, it is crucial to be able to identify mushrooms effectively before consuming them.

While there are some general guidelines and characteristics to help identify poisonous mushrooms, there is no definitive home test that can be relied on to distinguish between poisonous and edible mushrooms. Many mushrooms differ significantly across regions, so it is essential to have specific knowledge about the mushrooms found in your particular area.

One common feature of poisonous mushrooms is the presence of toxins, such as amatoxins, which are found in the deadly Amanita mushroom, also known as the "death cap." Amatoxins are heat-stable and cause rapid cell damage throughout the body, affecting the liver, kidneys, and central nervous system. Other toxins found in mushrooms include orellanin, which causes kidney failure, and psilocybin, which causes hallucinations.

To identify mushrooms, it is recommended to consult field guides, join local mycological groups, and seek expertise from mushroom identification experts (mycologists). These sources can provide detailed information and guidance on identifying the various mushroom species in your region. It is also important to be cautious when foraging for wild mushrooms and to familiarize yourself with both edible and toxic mushroom varieties in your area.

While there may be some general guidelines and characteristics to help identify certain types of mushrooms, there is no universal home test that can definitively distinguish between all poisonous and edible mushrooms. Therefore, it is always best to exercise caution and consult expert sources before consuming any wild mushrooms.

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