Diabetes: A study in aging

Diabetics experience long-term health difficulties, including atherosclerosis/heart attacks, peripheral vascular disease, hypertension, cataracts, kidney disease, neuropathies, male erectile dysfunction, osteoarthritis, and colorectal cancer. They also die, on average, 10 years earlier than non-diabetics.

In effect, diabetics compress their lives into a shorter period of time. They experience all the "complications" of aging at a younger age. People without diabetes, of course, can develop atherosclerosis, cataracts, kidney disease, etc., but they tend to do so later in life compared to diabetics.

One index of the rate of aging (but not chronologic age itself) is hemoglobin A1c, or HbA1c, a "moving average" of glycated hemoglobin, i.e., glucose-modified hemoglobin. Blood glucose glycates hemoglobin linearly and irreversibly; measuring HbA1c thereby provides an index of the last 60 or so days average blood glucose.

To put HbA1c values into perspective:

Average HbA1c of hunter-gatherers: 4.5%
Average HbA1c for Americans: 5.6%
American Diabetes Association definition of diabetes: 6.5% or greater
American Diabetes Association definition of adequate control of diabetes: 7.0% or less

Why do diabetics age faster? There are likely several reasons. One important reason is glycation, as indexed by HbA1c. Glycated proteins in the lens of the eye causes cataracts. Glycated proteins in cartilage leads to arthritis. Glycated LDL particles (apo B) leads to atherosclerosis. Glycated nerve cells causes neuropathy. And so on.

If glycation underlies many of the phenomena of aging, then we might surmise that:

1) The less you glycate, the slower you age.
2) The more you glycate, the faster you age.

Therefore, the higher the HbA1c, the faster you are aging.

What foods increase HbA1c? Carbohydrates. That bowl of slow-cooked, stone ground oatmeal? A one-hour after-eating blood sugar of 170 mg/dl is common. Your doctor says that's okay because it's below 200 mg/dl and you don't "need" medication yet.