Advanced Glycation End-products, AGEs, are a diverse collection of compounds that have been associated with endothelial dysfunction, cataracts, kidney disease, and atherosclerosis in both animal models and human studies. Not all involve glycation nor glucose, but the catch-all name has stuck.
There are a number of actively-held theories of aging, such as the idea that aging is the result of accumulated products of oxidative injury; a genetically pre-programmed script of declining hormones and other phenomena; genetic "mis-reading" that results in disordered gene expression, debris, and uncontrolled cell proliferation (e.g., cancer); among others.
One of the fascinating theories of aging is, cutely, the AGEing theory of aging, i.e., the accumulation of AGE debris in various tissues. Such AGEs have been recovered in lenses from the eyes, atherosclerotic plaque in arteries, kidney and liver tissue, even brain tissue of people with Alzheimer's dementia. AGEs perform no known useful physiologic function: They are relatively inert once formed (especially polymeric AGEs), they do not participate in communication, they make no contribution of significance. They simply gum up the works--debris. (AGEs are to health as the USDA food pyramid is to dietary advice: material for the junkyard.)
There are two general ways to develop AGEs:
1) Endogenous--High blood glucose (any blood sugar above 100 mg/dl) will permit glycation of the various proteins of the body. The higher the blood glucose, the more glycation will proceed. Glycation also occurs at low velocity at blood glucose levels below 100 mg/dl, though this would therefore represent the "normal," expected rate of glycation. Endogenous glycation explains why people with diabetes appear to age and develop all the phenomena of aging faster than non-diabetics (kidney disease, eye diseases, atherosclerosis, dementia, etc.). Hemoglobin A1c, HbA1c, is a readily-obtainable blood test that can show how enthusiastically you have been glycating proteins (hemoglobin, in this case) over the last 2 to 3 months.
A low-carbohydrate diet is the nutritional path that limits endogenous glycation leading to AGE formation. Restricting the most obnoxious carbohydrates, the ones that increase blood sugar the most, such as wheat, cornstarch, rice starch, potato starch, tapioca starch, and sucrose, will limit endogenous AGE formation.
2) Exogenous--AGEs (here especially is where the "AGE" label is misleading, since many other reactions besides glycation lead to such compounds) are formed with cooking at high temperatures, especially meats and animal products. Therefore, a rare steak will have far less than a well-done steak. A thoroughly baked piece of salmon will have greater AGE content than sashimi.
The forms of cooking that increase AGE content the most: roasting,deep-frying, and barbecuing. Temperatures of 350 degrees Fahrenheit and greater increase AGE formation.
Therefore, cooking foods at lower temperature (e.g., baking, sauteeing, or boiling), eating meats rare whenever possible (not chicken or pork, of course), eating raw foods whenever possible (e.g., nuts) are all strategies that limit exogenous AGE exposure. And minimize or avoid butter use, if we are to believe the data that suggest that it contains the highest exogenous AGE content of any known food.
If we connect the dots and limit exposure to both endogenous and exogenous AGEs, we will therefore not trigger this collection of debris that is likely associated with disease and aging. So following a low-AGE diet may also be an anti-aging strategy.
The New Track Your Plaque Diet, soon to be released on the Track Your Plaque website, has incorporated strategies to limit both endogenous as well as exogenous AGEs.