How you prepare the foods you eat can be just as important to your health as what you eat.
Research is showing that the way we cook our food is just as important as the kinds of foods we eat. This may explain why some foods, such as beef, are linked to many inflammatory conditions.
There are many chemical reactions that occur during the cooking of food. High heat has been shown to drastically decrease the nutrients in many foods, as well as cause damaging reactions with the proteins and sugars in those foods. These reactions have the potential to lead to specific diseases.
Advanced Glycation End Products (AGE’s) are a culprit in many disease processes but most notable in degenerative eye diseases such as cataracts, diabetes, heart disease, stroke, renal disease, aging and Alzheimer’s disease. AGE’s are a result of cooking foods at high temperatures and cooking sugars with proteins. Glycosylation is the act of glucose (blood sugar) binding to cellular proteins until the protein ceases to function properly. Excessive glycosylation leads to impaired bodily functions, decreased immune function, increased autoimmune disease, diabetes, and increased free radical damage throughout the body.
Another similar process is the Maillard reaction, which occurs during high temperature cooking. It consists of a series of interactions between proteins and sugars or oxidized lipids, which enhance the colour, flavour and texture of foods like bread crust, roasted meat, coffee aroma, and chocolate. This reaction negatively affects health, as it makes amino acid liberation from proteins during digestion impossible, which means they cannot be used later (i.e. lowers protein digestibility). It also has negative effects on blood sugar, and calcium and magnesium levels in the bones.
Research on glycosylation and the Maillard reaction supports the wisdom of limiting these products in your diet. The following in an excerpt from World’s Healthiest Foods about what creates these harmful products in your food and how to prevent them from forming:
“One of the greatest insults to nourishment in our modern, fast-paced, and processed food culture is the high heat at which so much of our food is cooked. We deep fat fry at 350-450 degrees; we fry on the stovetop in shortening and vegetable oils right up until their smoke points of 375-450 degrees; and we barbecue with gas grills that can reach temperatures of over 1000 degrees! This exposure of food to high heat may be convenient and quick, and it may fill the air with aromas that we savor, but it comes at a definite nutritional cost. Our food just wasn’t designed to withstand extremely high temperatures. Neither was the nutrients contained within our food. Nutritional research is just starting to catch up with the consequences of our high-heat approach. We’ve learned, for example, that some of the most mutagenic agents formed in cooking are called heterocyclic amines, and they are commonly found in barbecued beef, chicken, and pork cooked at 392 degrees or above. We even know what basic ingredients are required for these mutagenic agents to be produced: high temperature for more than a few minutes, free amino acids (from protein), creatine (or creatinine) and sugar. Without the high temperature component, the formation of heterocyclic amines does not occur. Direct flame grilling produces another of type of carcinogen called polyocyclic aromatic hydrocarbons, which may be just as bad as the heterocyclic amines. Researchers at Mt Sinai Medical found that foods cooked at high temperature contain greater levels of compounds called advanced glycation end products (AGEs) that cause more tissue damage and inflammation than foods cooked at lower temperatures. AGEs irritate cells in the body, damaging tissues and increasing your risk of complications from diseases like diabetes and heart disease. Those chemicals can be avoided by cooking meals at lower temperatures through using our Healthy Sauté, Healthy Steaming or Healthy Stir-Fry methods of cooking and also by cooking meats with foods containing antioxidant bioflavonoids, such as garlic, onion and peppers. Unfortunately, we’re not off the hook if we are vegetarian and don’t eat beef, chicken, or pork. Very recent research has discovered that a potentially toxic substance called acrylamide, a nerve-damaging compound in humans and clear cancer-causing agent in rodents, may be excessively formed when certain foods are cooked at high temperature. Potato chips are a key target of research interest here, as are some other foods, including flaked breakfast cereals, and roasted nuts. As is the case with heterocyclic amines, acrylamide does not appear to form excessively when high cooking temperatures are absent, provided that lower temperature cooking does not continue for a prolonged period of time (generally involving hours versus minutes). The problems with high-heat cooking are not restricted to creation of toxic substances, however. High-heat cooking is also problematic when it comes to loss of nutrients. Virtually all nutrients in food are susceptible to damage from heat. Of course, whether a particular nutrient gets damaged depends on the exact nutrient in question, the degree of heat, and the amount of cooking time. But in general, most of the temperatures we cook at in the oven (250-450 degrees) are temperatures at which substantial nutrient loss occurs. And although very short cooking at 212 degrees in boiling water produces relatively little nutrient loss, once boiling goes on for more than a very short period of time (a couple of minutes) the nutrient loss becomes significant. Up to 80% of the folic acid in carrots, for example, can be lost from boiling. Ditto for the amount of vitamin B1 in boiled soybeans. Even the high heats involved with commercial food canning rob foods of vast amounts of nutrients. In canned mixed vegetables, the vitamin C loss can be as high as 67%. In canned tomato juice, up to 70% of the original folic acid can be lost.
We’ve searched and searched through the nutrition research, and all of the evidence points to the same conclusion: prolonged, high-heat cooking is just not the way to go.”
Link here to the full article for further reading: http://whfoods.org/genpage.php?tname=george&dbid=122#answer