Fiddleheads: fugu for vegetarians

From my friend Erika:

Fiddleheads must definitely be well cooked in order to detoxify them. Boil them for at least 5 minutes and discard the water. If you want to serve them "raw", boil them, then chill them and call them raw, or else face risking the reaction Bob had if you actually eat them without boiling first (some individuals are more susceptible to their toxin than others). Stir frying or light steaming is not enough to detoxify them. If they taste bitter, don't eat them!

Note that ostrich fern fiddleheads are the least toxic. Bracken ferns have toxins that are carcinogenic and mutagenic and well known to cause bladder cancer in cows, so if you're going to collect them yourself, you need to be able to recognize the species. We have about 30 common fern species around here and the guidebooks generally only show the mature plants, not the fiddlehead stage, so getting starting with fiddlehead collecting on your own can be tricky.

Fiddleheads should be eaten in moderation and in season, since they contain thiaminase, which breaks down B vitamins in the body and can lead to vitamin B deficiency. While raw fiddleheads have been shown to contain vitamins A and C, nutritional analyses are on RAW fiddleheads, but this is meaningless since you can't eat them raw. I haven't seen any data on nutritional analyses of fiddleheads that show whether or not any vitamins remain after cooking and throwing out the water. So, they're a treat if cooked thoroughly, but not a nutritional staple by any means.

(Another food you must boil well before eating to detoxify is shell/dried beans, especially cranberry beans and kidney beans. Never, never eat these raw from the garden, or you'll get very, very sick. They need to be boiled at a high temperature to disable the phytohaemaglutanin. That's why they're safe from rodents in storerooms. Boil, don't simmer, until soft.)

People used to boil the heck out of vegetables for a reason--not to make them gray and slimy, but to denature any toxins. Cultivated foods have had the toxins bred out and more nutrition bred in, so they are much safer to eat raw or only slightly cooked. With wild, uncultivated foods, you really need to know what you're dealing with because many contain toxins to prevent predation. As long as people were used to gathering some of their foods wild, they knew they had to be careful about really cooking them well. But in the last 30-40 years, wild gathering has been replaced with virtually exclusive cultivated eating. This has allowed more culinary experimentation and crispier tastes to develop. But it has also meant that people have forgotten, or not even learned, the wisdom of their elders when dealing with wild foods. My grandmother used to boil all her vegetables for a long, long time, and warned me never to eat raw beans. Of course, I didn't listen to her, and that's how we ended up with bean poisoning. Not once, but twice, because we couldn't imagine that undercooked beans could make us sick.