McGee's On Food and Cooking goes through this. Basically, water soluble vitamins can be leached out in boiling, less in steaming. Fat soluble vitamins are less affected, but deep frying could remove some surface level vitamins and so on. Heat and age destroy some more.
The fresher and less cooked, the more nutritous. Cooked and eaten in sufficient volume, then it doesn't matter anymore.
More precision is available in the above mentioned text.
Phatch you are right about that and I think that is why we are starting to see such a "raw" food diet craze and even restaurants now. If I have my choice I prefer steaming or roasting vegetables such as asparagus or carrots as opposed to blanching them in boiling water and then sauteing them.
Just as an interesting aside -
Lysine, which is an important anti oxidant, is only absorbable from cooked tomatoes. Cooking would reduce some of the other vitamins so it's probably good to have a combination of raw and cooked tomatoes.
Regarding lysine. I take L-LYSINE whenever a fever blister strikes. Thanks to L-LYSINE fever blisters have a far shorter duration and intensity. L-LYSINE acts therefore as an antibiotic and analgesic to fever blisters.
I take two 500 mg tablets upon sensing the initial throbbing that accompanies the onset and continue taking two tablets throughout the blister's presence. I must say that L-LYSINE has been a godsend for me.
The most effective brand of L-LYSINE is Nature Made. None other.
Did you mean to say that lysine is "absorbable" or "furnished" from tomatos?
Organic compounds are, indeed, sensitive to microwaves. Out at the naval installation where I grew up there was a radar nicknamed the "Crow Killer" because everytime a raven would fly in front of the dish it would suddenly slam into the pavement lifelessly. It died. The raven's innards were fried by the radar's emissions that fell in the microwave spectrum.
I meant to say that Lysine is present in tomatoes ( i'm sure it's in other things, but I've only read about it in regards to tomatoes) and that the human body can't absorb the lysine from raw tomatoes, only cooked ones.
It may be more complex than that, and I'm not a nutritionist or doctor, but that is what I understand to be so.
PS: What is a fever blister?
A fever blister is a manifestation of the HERPES SIMPLEX TYPE I virus (type II is genital herpes, generally) and appears on the lip. Intense sunlight or spicey foods will cause an outbreak and sometimes they appear spontaneously. Affectionately, it's known as a COLD SORE.
Information from "New Foods for Healing" a Prevention Health Book: ...It's easy to get large amounts of lysine in your diet. An ounce and a half of provolone cheese, for example, has 1,110 milligrams. Two eggs provide 900 milligrams, and 1 cup of baked beans has 960 milligrams. Pork is a lysine powerhouse, with one broiled, center-cut loin chop providing almost, 2,000 milligrams.
Are you confusing lysine in tomatoes with lycopene (a very strong antioxidant found in tomatoes)?