Multiple studies revealed that dry heat-cooking of meats - grilling, smoking, frying, and baking at high temperatures is associated with production of toxic substances called advanced glycation endproducts (AGEs).
AGEs produce inflammation and increase oxidative stress, the two pathways leading to chronic diseases such as diabetes, cardiovascular disease, renal disease, and dementia, including Alzheimer's.
The body naturally generates AGEs at a small rate as a byproduct of our metabolism, when proteins or fats combine with sugars. Their formation is markedly increased in patients with clinical conditions characterized by high level of inflammation, like diabetes, heart disease, kidney disease, cancer, and autoimmune problems.
The body naturally rids itself of harmful AGE compounds, but it doesn’t eliminate them effectively when too many are ingested through food or the body is overwhelmed by stress, which eventually leads to disease.
AGEs are oxidants, so they corrode our body in the same way rust damages metal objects, if it’s allowed to build up. Oxidation depletes our natural reserves of antioxidants, which are the “good guys” since they can neutralize the corrosive effects of AGEs, but only up to a point.
When we dry cook meat or fat we create AGE-lipids that stick to our arteries and cause blockages, high blood pressure or heart trouble. Or they settle in our waistline as AGE-fat, causing inflammation, obesity, and insulin resistance.
AGEs also can cause proteins to stick together. With years, AGE-proteins become rigid. This is one reason why joints, muscles and tendons become stiff and inflexible over time. This is why blood vessels become thick and inelastic, a condition we call “hardening of the arteries”.
So why do we like them? AGEs are known to bring to raw nutrients those positive attributes we associate with our favorite meals. AGEs are responsible for the taste, appearance and the smell of foods we enjoy – the grilled burger and pizza and soft drinks and fried chicken; the bacon and corn chips and cookies. AGEs are at work whenever cooked food attracts our attention, awakens our senses and encourages us to take yet another bite, even when we’re already full.
The most effective way to reduce intake of foods high in AGEs is to modify cooking methods. In a study published in the June 2010 issue of the Journal of the American Dietetic Association, Uribarri and colleagues developed a guide to AGE dietary reduction. The researchers found a link between heat-processed foods and AGEs. They compared different types of cooking methods and found that dry heat promoted AGE formation by more than 10- to 100-fold above uncooked foods in all food categories. Meats high in protein and fat were likely to form AGEs during cooking, while carbohydrate-rich foods such as fruits, vegetables, and whole grains maintained low AGE levels after cooking. Foods cooked with moist heat, shorter cooking times, lower temperatures, and acidic ingredients such as vinegar or lemon juice produced the least amount of AGEs.
To minimize the exposure to AGEs change your cooking style: instead of grilling or frying, switch to stewing, steaming, and poaching.
We know that summer is still here, the grilling season is far from being over, so what could be done to minimize the damage:
use acid based marinade that contains lemon or other citrus fruit juices, or vinegar; it also will enhance the flavor of the food
cook on low or medium heat to avoid browning or charring food (indication that AGEs are present)
consume vegetables, rich in phytonutrients that can block the AGE effect, like broccoli, spinach, and other cruciferous vegetables
add antioxidant rich spices, like rosemary, curcumin or dark colored berries, like blueberries, blackberries, cranberries, and noni fruit.
For the advanced glycation end product (AGE) content of 549 foods, based on carboxymethyllysine content see: