When foods are cooked at temperatures above that of boiling water (100 C or 212F), sugar sticks to proteins and fats to form chemicals called Advanced Glycation End Products (AGEs). Eating food cooked at high temperatures markedly elevates tissue, blood and urine levels of AGEs to increase risk for diseases of inflammation such as cancers, arteriosclerosis, asthma, arthritis, diabetes, Alzheimer’s Disease, heart attacks and strokes; damage to the eyes and kidneys, and conditions such as cataracts, gum infections, nerve damage and muscle injuries in athletes.
How AGEs form in foods: When carbohydrates (chains of sugars) are cooked with proteins or fats at high temperatures and WITHOUT WATER, sugar binds to proteins or fats to form AGEs. When carbohydrates are cooked in water, they do not attach to protein and fat. Browning during cooking is a sign that AGEs are being formed. AGEs are found in grilled, roasted, broiled, fried or baked foods, and in coffee (made from roasted coffee beans).
Your body also makes AGEs whenever your blood sugar level rises too high. This is most likely to happen when you eat sugary foods and become inactive after eating. A high rise in blood sugar causes sugar to stick to cell membranes. Once there, sugar cannot get off and eventually destroys the involved cells. Blood sugar levels rise after you eat. If you exercise just before or after you eat, contracting muscles can draw sugar from the bloodstream without even needing insulin.
To reduce your exposure to AGEs:
- Avoid foods that cause a high rise in blood sugar, such as sugared drinks and foods with added sugars.
- Eat plenty of foods that do not cause a high rise in blood sugars such as raw, streamed or simmered vegetables and fruits.
- Restrict processed carbohydrates such as foods made from flour (bakery products and pastas).
- Use water-based cooking methods whenever possible: steaming, simmering, blanching or boiling. Water prevents the sugars from attaching to proteins and fats.
- Limit or avoid brown-cooked foods: those that are grilled, broiled, roasted, fried or baked.
References:
Am J Clin Nutr, June 2011
Am J Clin Nutr. May 2010
Neurobiol Aging, May 21, 2009
J Gerontol A Biol Sci Med Sci Sept 2010

A practicing physician for more than 40 years and a radio talk show host for 25, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is one of a very few doctors board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology.
Dr. Mirkin's latest book is The Healthy Heart Miracle, published by HarperCollins. His daily short features on fitness have been heard on CBS Radio News stations since the 1970's.
He has written 16 books including The Sportsmedicine Book, the best-selling book on the subject that has been translated into many languages. Dr. Mirkin did his residency at the Massachusetts General Hospital and over the years he has served as a Teaching Fellow at Johns Hopkins Medical School, Assistant Professor at the University of Maryland, and Associate Clinical Professor in Pediatrics at the Georgetown University School of Medicine.
Read more at www.drmirkin.com.

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