Like miles on an automobile, Advanced Glycation End-products, or AGEs, accumulate in our bodies over the years of our lives. AGEs are part of aging. They are also part of human disease.
AGEs result when glucose (as the glucose in table sugar, or sucrose, that enters the blood after consumption) modifies the various proteins in the body. Accumulated AGEs form the basis for many disease conditions like dementia, cataracts, osteoporosis, deafness, cancer, atherosclerosis, as well as aging itself. Most of the many complications of longstanding diabetes, in fact, are attributable to AGEs.
There's one readily available method that allows you to indirectly assess your recent AGE status: Hemoglobin A1c, or HbA1c.
HbA1c is a test often performed to gauge whether you are diabetic. Hemoglobin is the oxygen-carrying protein of red blood cells. Like all other proteins in the human body, hemoglobin becomes glycated in the presence of glucose. Hemoglobin glycation increases linearly with glucose: The higher the serum or tissue glucose level, the more glycation of hemoglobin develops. An index of glycated hemoglobin is therefore available as the common test, HbA1c.
Ideal HbA1c is 4.5% or less, i.e., 4.5% of hemoglobin molecules are glycated. Diabetics typically have HbA1c 7.0% or greater, not uncommonly greater than 10%. In other words, repetitive and sustained high blood glucose leads to greater hemoglobin glycation, or higher HbA1c. If HbA1c is high over an extended period of months to years, it indirectly indicates greater degrees of glycation of proteins in nerve cells, the lens of your eye, proteins lining arteries, and apoprotein B in LDL cholesterol particles. (Incidentally, levels of 6.5% or less are often dismissed by doctors because you don't "need" diabetes medication, despite the long-term health implications.)
If AGEs accumulate with aging, and high blood sugars lead to greater degrees of glycation, it follows that higher HbA1c marks a tendency for accelerated aging and disease.
Indeed, that is what happens in real life. People with diabetes, for instance, have kidney failure, heart disease, stroke, cataracts, etc. at a much higher rate than people without diabetes. People with pre-diabetes likewise share increased risk for all these conditions at an earlier age than people without pre-diabetes.
The higher your HbA1c, the greater the degree of glycation of other proteins beyond hemoglobin, the faster you are aging and subject to all the phenomena that accompany aging. So, that blood glucose of 175 mg/dl you experience after oatmeal may not be a good idea, nor the blood glucose of 157 mg/dl after a bowl of breakfast cereal. Such high blood sugars are not at all uncommon in non-diabetic people. In fact, they are the rule.
The lesson: Keep blood sugars and HbA1c low. First, slash carbohydrates, the only foods that substantially increase blood glucose. If you must eat carbohydrates, combine them with proteins and fats to blunt the rise of blood sugar. Second, maintain ideal weight, since normal insulin responsiveness requires normal body weight. Third, stay physically active, since exercise and physical activity exerts a powerful glucose-reducing effect.
While HbA1c cannot indicate cumulative AGE status, it can reflect your recent (preceding 60 to 90 days) exposure to this age-accelerating thing called glucose.