This is an article I recently found (http://www.innvista.com/health/nutrition/amino/pdamage.htm) saying that heating any food causes it to lose its nutritional value, and in many cases adds dangerous carcinogens that are harmful to your health.

I'd be very interested in hearing from Raw Food eaters about their experiences and any studies they might be familiar with regarding the issues raised in the article.

Protein Damage Through Heating

Protein structure is altered during heating; and, since most people do not eat their meat or eggs raw, this is a major factor to consider. Evidence is mounting indicating that heated animal protein may be a significant factor in coronary thrombosis since it reportedly causes a shortening of both the blood clotting time and the platelet clumping time. The amino acids in eggs are coagulated by heat and thereby lost to the body. Eggs also contain sulphur, which puts a heavy strain on the liver and kidneys.

During moderate heating of proteins, some of the cross-linkages that connect the peptide chains are split, making digestion easier. However, excessive heating results in linkages that are resistant to digestive enzymes. One resistant linkage, known as the Maillard or the browning reaction, is formed between lysine and carbohydrates. This occurs when an item has been held at a high heat for a long period of time. Commercial breakfast cereals fall in this category, and, not only are the proteins affected, but other nutrients are as well, necessitating additions falling under the label of "Enriched."

When barbecuing, burning fat drips onto an open flame producing polycyclic aromatic hydrocarbons (PAH's), which are dangerous carcinogens. They are also produced when foods are browned or fried. There are more than twenty known, with the two most notable being benzopyrene and quinoline compounds. They are also found in the waxy coating used on fruits and vegetable. The canning of high protein foods cause some formation, as does the fermentation and pickling of foods. Cooked meats do not pose the only threat; even browned or burnt crusts contain a variety of carcinogenic substances. People consume many grams of overcooked food each day. By comparison, these same dangerous materials is only ½ gram, which is equal to someone smoking two packages of cigarettes per day.

Several carcinogens are produced. Carcinogens are mutagens, that is, substances that change the genetic code of cells. When meats are barbecued, broiled, char-broiled, smoked, fried, or even cooked above a temperature of 212F, the production of these carcinogens explode. In fact, many of the chemicals used to produce cancer in lab animals have been isolated from cooked proteins.

During barbecuing, for example, the fat from the meat drips onto the charcoal producing benzopyrene which then filters back up into the meat. A one-pound, well done, charcoal -broiled steak contains 4-5 micrograms of benzopyrene, an amount equal to what a person would get from smoking 600 cigarettes, stated Dave Townsend, an industry researcher who testified before a Minnesota tobacco trial.

Smoked meats also produce this carcinogenic agent. In Iceland, the numbers of patients with stomach and intestinal cancers is greater than anywhere else in the world. Their disease is attributed to the large consumption of smoked fish. The soot from smoking and roasting foodstuffs (meats, fish, coffee, etc.); charcoal broiling of meats and fish, and hard liquor aged in charred wood caskets are just some of the established carcinogens.

Another carcinogen is a family called HAA's (heterocyclic aromatic amines). Researchers have discovered at least seventeen different kinds resulting from the cooking of muscle meats. Little or no HAA's are found in the cooking of such other protein foods as milk, eggs, tofu, etc. Research has also been done on the various kinds of cooking. Those wishing more information on these related studies, in English or in Spanish, can contact the National Cancer Institute at 1-800-422-6237. Remember, the higher the fat content of the food and the greater the temperature reached in cooking, the more carcinogens are produced.