High HbA1c: You're getting older . . . faster

Over the years, we all accumulate Advanced Glycation End-products, or AGEs.

AGEs are part of aging; they are part of human disease. AGEs are the result of modification of proteins by glucose. AGEs form the basis for many disease conditions.

Accumulated AGEs have been associated with aging, dementia, cataracts, osteoporosis, deafness, cancer, and atherosclerosis. Most of the complications of diabetes have been attributable to AGEs.

There's one readily available method to assess your recent AGE status: HbA1c.

Hemoglobin is the oxygen-carrying protein of red blood cells. Like other proteins, 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. Glycated hemoglobin is 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, higher HbA1c, and indicates greater glycation of proteins in nerve cells, the lens of your eye, proteins lining arteries, and apoprotein B in LDL cholesterol particles.

If AGEs accumulate as a sign of aging, and high blood sugars lead to greater degrees of glycation, it only follows that higher HbA1c marks a tendency for accelerated aging and disease.

Indeed, that is what plays out 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.

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 is not a good idea. 

The lesson: Keep HbA1c really low. First, slash carbohydrates, the only foods that substantially increase blood glucose. 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. Fourth, consider use of glucose-reducing supplements, an issue for another day.

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.

If your doctor refuses to accommodate your request for a HbA1c test, you can perform your own fingerstick test.

Comments (16) -

  • Dexter

    3/28/2010 3:08:24 AM |


    Dr Richard K. Berstein was interviewed on Mar 23 and was an eye opening regarding A1C and the incompetence of the mainstream medical community dealing with diabetics.  Author of many books for diabetics.


    Acceptable blood glucose levels of 250 and A1C levels of 7?  And not being accepted into diabetes clinics with A1C level less than 6.5  Criminal.

  • Denny Barnes

    3/28/2010 5:44:42 AM |

    HbA1c is a measurement of early glycation products which correlates with serum AGE levels, but is not a measure of advanced glycation end-products. For example, one Japanese study of cognitive decline in diabetes found, "Serum AGE levels were significantly associated with the impairment of complex psychomotor skills independent of HbA1c."

    You have written on the benefits of coffee.  While I share your love of coffee and believe coffee does not affect HbA1c, it clearly is one of the worst sources of AGEs.

  • Anonymous

    3/28/2010 1:12:09 PM |

    Use a BG meter to check effect of meals/foods on BG peaks, as described in this thread:

  • Anonymous

    3/28/2010 1:32:08 PM |

    btw, the case of high A1C with normal fasting BG is often due to high rates of gluconeogenesis (glucose from protein) that keeps BGs high between meals, but drops by morning as all remaining protein gets digested overnight.  A high rate of gluconeogenesis is often characteristic of insulin resistance, and is what forces many to eventually need the help of drugs to control BGs (i.e., reducing carb intake may not be enough to keep BGs low, and you're stuck consuming a certain amount of protein).

  • Carl M.

    3/28/2010 1:41:08 PM |

    Question: does this test measure just proteins reacted with glucose or also those reacted with fructose? I recall hearing somewhere that fructose was seven times as reactive.

  • Dr. William Davis

    3/28/2010 2:18:52 PM |

    Exactly right, Denny.

    HbA1c can only provide an indirect indicator, and only a short-term one at that. However, it's better than no indicator at all.

  • DrStrange

    3/28/2010 4:35:55 PM |

    " the case of high A1C with normal fasting BG is often due to high rates of gluconeogenesis (glucose from protein) that keeps BGs high between meals, but drops by morning as all remaining protein gets digested overnight."

    Also, can result from too frequent eating.  By adding a couple light, between meal snacks to my 3 meals per day I jumped my A1c from 5.1 to 6 in a few months.  Won't do that again!

  • Anonymous

    3/28/2010 9:11:18 PM |

    Dr. Davis,

    Have you ever looked into the potential for substances like taurine, benfotiamine, pyridoxamine, carnosine?  I've seen passing mention of these as potential glycation inhibitors.

    I've also seen sources that suggest that R-ALA and ALCAR can be of possible help in reducing glycation damage.

    While the comment in your post seems to point a bit more to the latter, I realize that you mentioned that glucose-reducing supplements are a topic for another day. But perhaps this can add to the mix for a possible future post on those topics.

    Doug Rafferty

  • Anonymous

    3/29/2010 12:59:45 AM |

    I've now gone back and read all the recent blog posts about BGs made by Dr. Davis, and would like to point out several issues:

    - first, it's great to see someone finally pushing BG measurements for non-diabetics; however, there's a lot to know about this, and I encourage others to read the imminst thread referred to in comment #3 above

    - for low-carb dieters with insulin resistance, their average BG (and A1C) will usually be dominated by glucose produced from protein digestion (i.e., it's not just about carb intake)

    - the most accurate and precise meter I've seen is AccuChek Aviva, where precision is mainly determined by strip quality, and crummy strips will cost you a lot more money and blood, since you'll need to make a lot of extra measurements (i.e., with crummy strips you may have to average 3 results to get an accurate number)

    - disease risk rises exponentially with BG levels, which is why peaks matter most

    - the time to your peak BG after meals depends on so many factors that you'll have to determine that yourself (i.e., don't assume 1 hour; mine is 30-60 minutes for most meals)

    - exercise after meals can reduce your BGs to fasting levels, but they will soon rise again due to continued protein digestion (or even low-glycemic carb digestion); so the benefit of regular exercise is mainly in a general lowering of insulin resistance, and greater glucose uptake by muscle mass when at rest

  • stcrim

    3/29/2010 1:09:07 AM |

    Cinnamon - a simple recipe with a double punch.  Take a couple of cups of almonds and wet them.  Shake them in a bag with a couple of teaspoons of Ceylon Cinnamon.  Make sure you use Ceylon for best Blood Sugar results.

    Preheat your oven to 350.  Spread the almonds on a cookie sheet.  Pop them in the oven and turn it off.  20 to 30 minutes later the Cinnamon will be dried to the almonds - let cool and enjoy.

    What was it they were eating in the 20s and 30s to cause heart disease?  My grandfather died in 1934 of quote, acute indigestion.

  • Anonymous

    3/29/2010 1:43:44 AM |

    With respect to weight loss and BG measurements, some of you may find my story encouraging:

    - starting at 205 lbs, I lost about 20 pounds basing decisions mainly on carb counts and low glycemic index

    - after getting a meter and eliminating foods causing high-post meal BGs (such as oatmeal!), I dropped another 10 pounds

    - after fixing a testosterone deficiency (andropause), I dropped another 10 pounds

    which puts me at about 165 and BMI near 22.  (All that was done over the course of about 5 years, but it took me that long to figure out this stuff!)

  • stcrim

    3/29/2010 1:43:44 AM |

    Oops! I forgot to mention I use a little Stevia with the Ceylon Cinnamon and almonds.  It also works great with walnuts.


  • Anonymous

    3/29/2010 2:33:34 PM |

    To my above list, I'd like to add a few points about "grazing":

    - from the plots in the blog, it appears that evidence of "stacking" comes mainly from excessive fructose consumption; my own experience with a TG meter does not show stacking of TGs when grazing on fat-rich mini-meals

    - it's irrelevant whether grazing is "self-indulgent"; diet needn't be torture, and you're unlikely to stick with something you don't enjoy doing

    - it's also irrelevant whether grazing is "unnatural", since the optimal diet (to reach, for example, age 100) is unlikely to be one followed by people who rarely lived beyond age 50; to reach extraordinary ages, you'll likely need to do extraordinary things (niacin? fish oil capsules? D3 capsules? etc.)

    - peaks matter, and fewer meals means larger peaks (as well as increased acid reflux, esp. bad when large meals are consumed late in day)

    imho, i don't think the data currently exists to prove the case one way or the other, and suspect that the optimal solution will turn out to be very person-specific

  • Anonymous

    3/29/2010 6:50:12 PM |

    More thoughts on "stacking": If one spread one's consumption across 24 hours, then food would be being burned at exactly the same rate as it was being consumed, and no significant stacking would occur. Thus stacking results from compressing consumption into smaller time frames. In fact, the ultimate "stack" is formed by consuming a single meal per day (i.e., all the TG and BG is forced to pile up over a very short time frame).

    The caveat to this is that it may be the case that larger TG and BG peaks create more efficient processing (i.e., ice cream is somehow better handled after a big meal than when consumed in isolation), or that the benifits from lows between meals outweigh all the highs during meals. But I remain skeptical that such stress (high peaks, high insulin, etc.) is ultimately a good thing (esp. since I've already taken the trouble to control acid reflux by spreading intake across the day).

    But wouldn't be surprised either way. There's already a camp that believes that BG spikes are necessary for optimum bone formation, etc., so who knows?

  • Anonymous

    3/30/2010 9:38:06 PM |

    I've found every article in this blog really interesting and helpful and everything seems to make a lot of sense.
    But I still fail to see how it fits for people that don't want/need to loose weight.
    Say a 190pound healthy athlete with a very active live.
    How do you feed him without gazing, only two meals per day, 50g carbohidrates per day and 40g of fat per meal?
    How would you feed Michael Phelps?

  • Anonymous

    3/31/2010 3:55:27 PM |

    Dr. Davis,

    In this latest post, you said "Fourth, consider use of glucose-reducing supplements, an issue for another day."

    I would very much like to read your thoughts on these supplements and would look forward to a blog post on this topic.