Here’s a discussion on a very important–and empowering–topic: hemoglobin A1c, or HbA1c. It sounds dull and tedious, I know, but if understood and put to work properly yields enormous power in health, preservation of youth, and weight loss.
I was planning on writing a new discussion about it, but decided instead to share an excerpt from the original Wheat Belly book that provides the essential background information on this important number. (The full discussion can be found in Wheat Belly on page 130, Chapter 9: Cataracts, Wrinkles, and Dowager’s Humps: Wheat and the Aging Process).
The Great Glycation Race
There is a widely available test that, while not capable of providing an index of biological age, provides a measure of the rate of biological aging due to glycation. Knowing how fast or slow you are glycating the proteins of your body helps you know whether biological aging is proceeding faster or slower than chronological age. While AGEs [Advanced Glycation End-Products] can be assessed via biopsy of the skin or internal organs, most people are understandably less than enthusiastic about a pair of forceps being inserted into some body cavity to snip a piece of tissue. Thankfully, a simple blood test can be used to gauge the ongoing rate of AGE formation: hemoglobin A1c, or HbA1c. HbA1c is a common blood test that, while usually used for the purpose of diabetes control, can also serve as a simple index of glycation.
Hemoglobin is the complex protein residing within red blood cells that is responsible for their ability to carry oxygen. Like all other proteins of the body, hemoglobin is subject to glycation, i.e., modification of the hemoglobin molecule by glucose. The reaction occurs readily and, like other AGE reactions, is irreversible. The higher the blood glucose, the greater the percentage of hemoglobin that becomes glycated.
Red blood cells have an expected life span of sixty to ninety days. Measuring the percentage of hemoglobin molecules in the blood that are glycated provides an index of how high blood glucose has ventured over the preceding sixty to ninety days, a useful tool for assessing the adequacy of blood sugar control in diabetics, or to diagnose diabetes.
A slender person with a normal insulin response who consumes a limited amount of carbohydrates will have approximattely 4.0 to 4.8% of all hemoglobin glycated (i.e., an HbA1c of 4.0 to 4.8%), reflecting the unavoidable low-grade, normal rate of glycation. Diabetics commonly have 8, 9, even 12% or more glycated hemoglobin–twice or more the normal rate. The majority of nondiabetic Americans are somewhere in between, most living in the range of 5.0 to 6.4%, above the perfect range but still below the “official” diabetes threshold of 6.5%. In fact, an incredible 70% of American adults have an HbA1c between 5.0% and 6.9%.
HbA1c does not have to be 6.5% to generate adverse health consequences. HbA1c in the “normal” range is associated with increased risk for heart attacks, cancer, and 28% increased mortality for every 1% increase in HbA1c. That trip to the all-you-can-eat pasta bar, accompanied by a couple of slices of Italian bread and finished off with a little bread pudding, sends your blood glucose up toward 150 to 250 mg/dl for three or four hours; high glucose for a sustained period glycates hemoglobin, reflected in higher Hba1c.
HbA1c–i.e., glycated hemoglobin–therefore provides a running index of glucose control. It also reflects to what degree you are glycating body proteins beyond hemoglobin. The higher your HbA1c, the more you are also glycating the proteins in the lenses of your eyes, in kidney tissue, arteries, skin, etc. In effect, HbA1c provides an ongoing index of aging rate: The higher your HbA1c, the faster you are aging.
So HbA1c is much more than just a feedback tool for blood glucose control in diabetics. It also reflects the rate at which you are glycating other proteins of the body, the rate at which you are aging. Stay at 5% or less, and you are aging at the normal rate; over 5%, and time for you is moving faster than it should, taking you closer to the great nursing home in the sky.
Foods that increase blood glucose levels the most and are consumed more frequently are reflected by higher levels of HbA1c that in turn reflect a faster rate of organ damage and aging. So if you hate your boss at work and you’d like to hasten his approach to old age and infirmity, bake him a nice coffee cake.
Get your HbA1c measured–a common and inexpensive blood test–and you will know how rapidly you are glycating. Levels often regarded as “normal” or benign, such as 5.5%, are still associated with increased health risks and accelerated glycation and aging. This is why, in the Wheat Belly lifestyle, we work to keep HbA1c no higher than 5.0%.