For what it's worth: Some years ago a mushroom hunter told me that a friend of his who was a mycologist advised him to stay away from all agaric mushrooms (of which the portabella is one of the largest) because they were very carcinogenic (cancer causing). Unfortunately most of those little white ones in the grocery stores are all agarics, too. He said his friend was warned to stfu about his research.I too had heard that mushrooms contain carcinogens, so I did some internet investigation, so as always, take it with a grain of salt.
I don't want to rain on anyone's picnic--but just to toss this out there. By the way, the friend said some mushrooms seemed to have cancer-fighting qualities (e.g. shitakes) so it depends on the 'shroom.
Almost universal in the articles I read was the agreement that cooking mushrooms destroyed many of the hyrdazines found in mushrooms. I'm yet to eat a raw mushroom, doubt it tastes any good, and the studies that found mushrooms to cause cancer fed ridiculous amounts of raw mushrooms to mice and rats: 3 days a week of nothing but fresh, raw mushrooms...yuck. Even a mushroom lover like me might have them with 3 meals a week, not three days worth!
Next is an article by what I suspect is some pseudo-consumer group defending the use of synthetic pesticides, but that doesn't mean it's information is entirely false and provides a good perspective at just how dangerous the raw mushroom is:
So a bottle of beer contains 28 times more carcinogens than a raw mushroom, not exactly something I wanted to discover!
HERP Daily human exposure percentage
EDB: workers' daily intake, high exposure
Formaldehyde: workers' average daily intake
Comfrey-pepsin tablets (9 daily), from comfrey root
Beer (12 ounces) from ethyl alcohol
Mushroom, one raw (15 g) from hydrazines
Speaking of alcohol, it's not surprising an article promoting the health of Red Wine on Google News caught my eye today. Typical of most the food reporting of today it has to be sensationalized and promise health with ease, forget changing habits or having to work for that slender body: you can eat high-saturated fat foods and lose weight, just don't eat that bland potato because it's full of carbs! Well now according to a Telegraph article you can Lose weight on red wine diet! Unfortunately if you actually read the article or it's counterpart on Forbes you realize that the Telegraph's headline is as substantive as "blood-type" diet fads:
"Native resveratrol from red wine or nutraceuticals cannot reach therapeutic levels in man," he said. "You would need to drink hundreds of glasses of red wine...in a day to get a therapeutic dose."Well so much for that easy and fun fix to obesity and living longer...
It always has fascinated me how we take our food and where it comes from for granted and are more interested in Britney Spear's sex-tapes and the like than what we put in our bodies and take from the earth. But mushrooms, while not promising the miracles of red wine that reduces weight, do have a lot to offer besides not providing a significant amount of the carcinogen hyrdrazines when cooked. They provide substantial, if not complete, protein, iron (an important mineral that is more difficult for vegetarian/vegan to obtain), fiber, various other vitamins, and are a strong source of anti-oxidants. It'd be difficult to hunt for a food that provides all that for so few calories and yet tastes so good (and is as good a meat-substitute you'll find).