How toxic are raw mushrooms?

1. Mushrooms are increasingly on the menu. No wonder, because they are tasty, healthy and inexpensive. However, eating the mushrooms raw is often discouraged, because they would then be poisonous. But is that really so?

1. Although we Dutch still find mushrooms a bit scary (unlike the French, Italians and Germans, we do not go out en masse with baskets to look for them in the woods ourselves) , the ordinary white mushroom or agaricus bisporus has become a familiar sight on our table. It tastes fairly neutral, is easy to get and prepare, and in addition, it is not expensive. We rarely need more. Yet this friendly white toadstool with its round head does not seem completely harmless. For example, the Nutrition Center urges us not to eat him raw. In raw form, it contains the poison agaritine, a poison named after the mushroom itself, which chemists refer to with the somewhat more complicated name β-n [!γ-1 (+) -glutamyl] -4-hydroxymethylphenylhydrazine. On the site of our national nutrition educator you can read about agaritine: "this substance is especially toxic to humans in larger quantities and is also possibly carcinogenic". How about that?

Battle of the arm

1. Actually, the Nutrition Center doesn't seem to know for sure either. After all: "A few slices of raw mushrooms, for example in a salad, cannot hurt". And also from that "especially in larger quantities toxic to humans" expresses uncertainty, as does from that "possibly carcinogenic". Agaritine is a hydrazine and there is still much uncertainty about the effects of hydrazines on human health. There are studies that show that agaritine has led to tumor formation in mice in a number of cases, while other studies indicate that certain degradation products of agaritine (substances that the body produces when processing agaritine) can make changes to the genetic material.]

"Everything is poisonous"

1. Anyone who is skeptical now and objects that "nowadays everything is even poisonous" is both right and wrong. After all, the late medieval Swiss researcher P.A.T.B. von Hohenheim (1493-1541), founder of modern toxicology or the theory of forgiveness, already wrote that "the dose makes the poison", in other words: everything is ultimately toxic, as long as the dose is high enough. This even applies to pure water: anyone who drinks ten liters of tap water in a few minutes has a high risk of death from an acute disturbance of the electrolyte balance. This makes toxicology a complicated science and also explains the uncertainty in the words of the Nutrition Center.

Heat, prepare, store

1. In 1982 researchers at the University of Nebraska (USA) published a study that showed that the concentration of agaritine in mushrooms, initially 0.4 to 0.7 mg per gram, increased 2 to 47 percent decreased after a week of refrigeration and by 36-76 percent after two weeks of refrigeration. Heating fresh mushrooms reduced the agaritin content by about 32 percent, which would indicate that mushrooms are even better left to lie than boiling. Remarkably, no measurable amounts of agaritine were found in canned mushrooms and mushroom soup. A 1990 Japanese study showed similar results.

Conclusion

1. The Netherlands Nutrition Center is right in that it is wise to eat raw mushrooms in moderation, and to the extent that this is actually… to a slightly lesser extent… also applies to heated mushrooms and even for any other food. After all, what von Hohenheim wrote in all its simplicity five hundred years ago is still true: you can literally ingest too much of everything, and that is not good for you. Even more important than "eat little or no raw mushrooms" is and remains "eat as varied as possible". Everything in moderation!