Hey, bilko:
It is not nitrates, but nitrites which, when cooked under high heat with proteins can convert to nitrosamines, many of which are proven carcinogens.
I doubt the statement that nitrates convert to nitrites by salivary processes, and I think it takes a bit more digestive efforts to rock this reversible reaction toward the less stable nitrite. Cows require many stomachs to convert the nitrogen compounds into amines and ammonia.
Both nitrates and nitrites were and are used to preserve meats, and you probably know that it was widely believed that the British Navy used saltpeter to control certain urges amongst their ranks, especially spiking their food prior to docking at foreign ports. There is probably not any truth to that rumor, since such dosages are too difficult to control in the first place, and the amount to preserve meat is no where near that required to produce therapeutic effect even in asthma.
People eating any kind of preserved meats probably get hundreds of times more nitrate/nitrite than they could ever get from vegetables. And these same people have been shown to have higher rates of intestinal cancers than the general population.
Nitrogen levels in vegetables increase in inverse proportion to water, so just keep plenty of water on the crops and we'll be fine.
Cancer? We should not worry about that very much, eating enough raw almonds can help protect us to some extent. I have a book, written by a local cancer-ward nurse entitled "The Little Cyanide Cookbook."
How's the Serpentine today?
John
