Normal fasting glucose with high HbA1c

Jonathan's fasting glucose: 85 mg/dl
His HbA1c: 6.7%

Jonathan's high HbA1c reflects blood glucose fluctuations over the preceding 60-90 days and can be used to calculate an estimated average glucose (eAG) with the following equation:

eAG = 28.7 X A1c – 46.7

(For glucose in mmol/L, the equation is eAG = 1.59 × A1C - 2.59)

Jonathan's HbA1c therefore equates to an eAG of 145.59 mg/dl--yet his fasting glucose value is 85 mg/dl. 

This is a common situation: Normal fasting glucose, high HbA1c. It comes from high postprandial glucose values, high values after meals. 

It suggests that, despite having normal glucose while fasting, Jonathan experiences high postprandial glucose values after many or most of his meals. After a breakfast of oatmeal, for instance, he likely has a blood glucose of 150 mg/dl or greater. After breakfast cereal, blood glucose likely exceeds 180 mg/dl. With two slices of whole wheat bread, glucose likewise likely runs 150-180 mg/dl. 

The best measure of all is a postprandial glucose one hour after the completion of a meal, a measure you can easily obtain yourself with a home glucose meter. Second best: fasting glucose with HbA1c.

Gain control over this phenomenon and you 1) reduce fasting blood sugar, 2) reduce expression of small LDL particles, and 3) lose weight.  

Comments (24) -

  • Mark

    3/23/2010 5:56:04 PM |

    So what is the basic recommendation here?
    Eat meat, nuts, vegetables, no starch, no fruit? A ketogenic diet?

    It looks like the recommendation is to avoid blood sugar spikes primarily. I would think that insulin is less of a worry because insulin doesn't necessarily mean that sugar is in the system (dairy for example).

    Some clarification would be greatly appreciated. Thanks

  • Anonymous

    3/23/2010 6:44:31 PM |

    Dr. Davis, my husband has the opposite problem, can you (or anyone else) explain it?  His 1-hour postprandial glucose never exceeds 90 and yet he has an HBA1C of 5.9.  We have checked his glucose at different times and it never goes over 100.  He is on a very low carb diet.  

    His HBA1C indicates an average blood glucose of 123, but we never see readings this high.  Is there something else that can glycating hemoglobin and thus show an elevated HBA1C reading?

  • Anonymous

    3/23/2010 7:03:19 PM |

    What would be considered an optimal (or at least good) HbA1c level? And same for fasting glucose?

    I have noticed my fasting glucose tends to vary, between 80-95, with my HbA1c at 4.6.

    Curious also if there is any data on HbA1c correlating directly with triglyceride levels.

    My own trig values are higher than I like, around 125-150, yet I limit carbs, use fish oil, and think my HbA1c number is relatively decent.  So wondering if carbs/glucose isn't my problem, what else raises triglycerides?

  • Jake P.

    3/23/2010 10:30:18 PM |

    Dr Davis, do you have any recommendations on blood glucose test meters, as far as brand/model? Also, I'd prefer something that doesn't require a prescription, if possible.

  • Dr. William Davis

    3/24/2010 1:41:43 AM |

    Anon--

    The only two causes I am aware of are 1) iron deficiency anemia, and 2) hemoglobin variants.

    Also, are you confident of the accuracy of your blood glucose meter? You can check it by running side-by-side glucoses with a blood draw.

  • Dr. William Davis

    3/24/2010 1:42:31 AM |

    I've had good experiences with One Touch Ultramini, Aviva, Relion, and Accuchek meters. All are available without prescription.

  • Anonymous

    3/24/2010 5:26:17 AM |

    This is exactly why everybody should have a blood glucose meter, and know their numbers.

    While I have not been diagnosed as having type 2 diabetes, I was darned close.  My meter, and the information found here and in the blogs that link to and from it, have helped me to lose about 3 pounds per week for the past 6 months, and not be hungry or feel deprived.

    I was like Jonathan.  Until 6 months ago my fasting glucose was always under 100.  Now that I am managing to keep my average BG reading, including post prandial readings, under 95, I have stopped suffering from the inflammatory symptoms I've had for a decade.

    My meter and initial 100 test strips was the best under $50 purchase I've ever made.

    Thanks for the USEFUL information I get at The Heart Scan Blog.

  • Alfredo E.

    3/24/2010 2:52:07 PM |

    Hi All. I eat a low carbs diet and I have the a high fasting glucose, 95-105, but a low postprandial, 85-100.

    I also exercise everyday and do Intermittent Fasting.

    What could be the mechanism working here?

    Thanks for your ideas.

    Alfredo E.

  • Anonymous

    3/24/2010 3:20:00 PM |

    David Mendosa has a good blog/site/comments... on diabeties for many things A1C, food, low carb, etc. Check him out at www.mendosa.com
    Look under "health central" or

    http://www.healthcentral.com/diabetes/c/17/75106/david-guide-a1c-6-0

    For A1C guidance.

    He seems to lean away from strict AHA, ADA, and government things that do not work for him.

    His meter data is getting a little dated, and he does not specify exact things like he states vitamin D, as opposed to stating: D3. And he seems to be a little soft about major statements, possible law suit shy.

  • Anonymous

    3/24/2010 4:01:15 PM |

    I'm curious why you believe that gaining control over postprandial glucose will result in lower *fasting* glucose.  Is there a mechanism for this?  I've found that my fasting glucose hasn't fallen since I started the TYP diet 3 months ago; it's still in the mid to high 90s -- even though my one hour glucose is rarely much higher than that.

  • Anonymous

    3/24/2010 6:40:34 PM |

    Responding to Dr. Davis' comment:
    "The only two causes I am aware of are 1) iron deficiency anemia, and 2) hemoglobin variants.

    Also, are you confident of the accuracy of your blood glucose meter? You can check it by running side-by-side glucoses with a blood draw."

    I don't think he has iron deficiency anemia unless high ferritin level indicates that?  His ferritin level was 320 at the time he got the HBA1C of 5.9.  What are hemoglobin variants?

    We have the Accuchek meter and have also had fasting and post-prandial lab tests done and the meter seems to be in the ballpark.

    Thank you very much for your reply.

  • Anne

    3/24/2010 9:28:20 PM |

    My fasting was below 100. My A1C was 6.5. A OGTT spiked at 202. My doctors told me as long as my fasting BG was good, I did not have to worry as I only had insulin resistance not diabetes. That was 10 yrs ago.

    A year ago I bought a glucometer and started eliminating foods that spike my BG. My last A1C was 5.5.

    I wish I could get a hold of the results of my OGTT from 40 yrs ago. I was told it was slightly abnormal but I did not have diabetes. How much damage has been done from elevated postprandial blood sugars?

  • Anonymous

    3/25/2010 12:20:28 AM |

    Dr. Davis,

    Would you anticipate that a healthy 25 year old would obtains similarly high postprandial sugars to those meals?  Or do young, healthly, slim people have high glucose tolerance, and hence low postprandial responses to sugar?  I've seen many articles featuring sports stars who subsist on high carb, low fat diets, such as rafael nadal, roger federer, tiger woods... I find it hard to believe they exceed 120 mg/dl postprandially...

    David

  • mikyy748

    3/27/2010 5:31:11 AM |

    Please help with an explanation ! My last meal of the day (with NO carbs) is around 4PM. At 9-10PM, my glucose test shows about 100-105. But... in the morning the test shows 125-130. How is it possible?!

  • Anonymous

    4/10/2010 4:37:12 AM |

    Veeerrrrry interesting!

    I have been on an extremely resrricted carb diet for several months.  My One Touch (and my wife's, she's T1 on a pump) my glucose levels never vary from 100-120 with the vast majority right around 110-113. Tests are run about once a day at various times including 1-2 hours post prandial.

    At my PCP's office (she's also an endocrinologist) today, her office machine complained of an HbA1C of 20+ and wouldn't give a reading, while it did report my other lipid levels, most moderately elevated as usual.

    Tubes were drawn for processing by a lab.  Of course it's the weekend and I'm obsessing about it... sigh.
    I worry that my low carb lifestyle might be masking what would be high glucose readings which is not very logical, or if something is wrong with my blood such as anemia.  A quick google and here I am.

    I wonder if this is common for extremely low-carber diabetics?

    Am on low doses of Diovan, HCTZ and colchicine...

    Thanks to all for any thoughts.
    -Ron

  • Anonymous

    4/13/2010 2:26:58 PM |

    Thanks to all who commented ;)

    Lab work came back with an HbA1C of 5.9, so the office machine was just being stupid as hoped/mostly expected.

    Good luck to everyone else.

  • mongander

    4/27/2010 11:22:25 PM |

    This MedScape article doesn't make sense.  It claims that <6 may be too low...That >7 has a better all cause mortality.
    http://www.medscape.com/viewarticle/720391

  • William A. Ryan

    7/15/2010 1:32:59 PM |

    FYI, another possible cause of abnormally high HbA1c is Vitamin B12 and/or folate deficiency.  This causes anemia with low red blood cell turnover, so any given Hb molecule is floating around longer, and thus has a higher probability of glycation.

  • Helena

    9/29/2010 11:01:56 PM |

    So.. I just started testing my blood sugar again today... first reading was 90
    Then I had lunch. Rice and curry with coconut milk (probably loaded with sugar) and it went from 156 to 258 to 124 in 2.5 hours after that meal... I am a little concerned.

    Think I will go back on my low carb diet ASAP!

  • Helena

    9/30/2010 3:22:01 PM |

    Let me correct my numbers... I didn't have them in front of me when I wrote the previous post so here they are:

    Lunch was Rice, shrimp, coconut milk based curry pot

    Blood levels:
    60 min after - 193
    90 min after - 217
    130 min after - 258
    2.5 hrs after - 140

    This morning I had a reading of 89 and after having my protein shake with cream and water it was 106...

    Def going to go back to my low carb diet asap!
    Thanks for a great blog full of valuable information and help to get back on track.

  • Anonymous

    10/15/2010 2:05:41 PM |

    This is a recent day of testing. 90 minutes after eating 50 grams of processed brown flax, my BG was about 117, but it also depends on what I eat the night before. 2 hrs after eating 8 oz hummus with tahini, my BG was 101. 1 hr after eating a 143 gram (quick rolled) oat cake with 95 grams chocolate syrup with a lot of sugar and water, my BG was 120. Next day fasting BG was 120. Carbs do a good job of BG stabilization, although I'm trying to decrease some carbs and lower my fasting BG. I will try soymilk, and less carbs.

  • H Saleem

    11/22/2010 9:04:14 PM |

    Hi, Let me add my 2Cs. The objectives for diabetics and pre-diabetics are poles apart and confusing the two can  lead to irreparable loss for the pre-diabetics and those with insulin resistance.  

    For diabetics, when the disease is well established, the focus is on minimizing the harm i.e. to minimize the blood sugar level. Elevated blood sugar does so much harm in the long run that it should be kept under control through any means possible: diet, exercise, medicine, weight loss etc. When one plan and/or drug regimen fails to control the blood glucose level, it is replaced by another, all the time focusing on maintaining optimum blood glucose levels resulting in normal (for diabetics) readings on fasting glucose, HbA1C etc. I am not fully aware but possibly there is no mainstream healthcare regimen or drug that focuses on  reversing the disease or trying to minimize diabetes damages (other than those caused by high blood glucose) like destruction of pancreatic cells.

    For pre-diabetics and those with insulin resistance, the focus should NOT be on lowering blood glucose level DIRECTLY. For pre-diabetes, it is possible to keep on "travelling" towards diabetes in reality but assuming otherwise just because some "local" interference does not let the blood sugar rise. So if you start taking any alpha-glucidase, your postprandial reading will not rise much. But this does not mean that you have controlled pre-diabetes. The causes are all there like being over-weight, lack of exercise bla bla. And your body's normal ability to regulate blood sugar keeps on deteriorating ultimately leading to a point when the alpha-glucidase alone will not be sufficient. So when pre-diabetes is treated like diabetes, it can lead to actual diabetes. This is because here the focus should not be on lowering blood glucose levels or "treating" the condition but REVERSING it. In other words the goal should be to transform the body back to the point where it can naturally process the foods while keeping the blood glucose levels and HbA1C levels in normal range. All this without the help of any drugs or special diet or aids. And for this the usual solutions are already well known: weight-loss, exercise etc.

    The moral of the story is that if you are pre-diabetic, you can keep yourself happy by eating almonds, vinegar or psyllium with meals to "show" you that your post-prandial glucose levels are in range. This can be done by eating a low-carn diet or taking diabetes drugs. But if keep the same weight, continue the same eating habbits, and do no exercise then you are possibly doing nothing to prevent a preventable disease.

  • H Saleem

    11/22/2010 9:04:58 PM |

    Hi, Let me add my 2Cs. The objectives for diabetics and pre-diabetics are poles apart and confusing the two can  lead to irreparable loss for the pre-diabetics and those with insulin resistance.  

    For diabetics, when the disease is well established, the focus is on minimizing the harm i.e. to minimize the blood sugar level. Elevated blood sugar does so much harm in the long run that it should be kept under control through any means possible: diet, exercise, medicine, weight loss etc. When one plan and/or drug regimen fails to control the blood glucose level, it is replaced by another, all the time focusing on maintaining optimum blood glucose levels resulting in normal (for diabetics) readings on fasting glucose, HbA1C etc. I am not fully aware but possibly there is no mainstream healthcare regimen or drug that focuses on  reversing the disease or trying to minimize diabetes damages (other than those caused by high blood glucose) like destruction of pancreatic cells.

    For pre-diabetics and those with insulin resistance, the focus should NOT be on lowering blood glucose level DIRECTLY. For pre-diabetes, it is possible to keep on "travelling" towards diabetes in reality but assuming otherwise just because some "local" interference does not let the blood sugar rise. So if you start taking any alpha-glucidase, your postprandial reading will not rise much. But this does not mean that you have controlled pre-diabetes. The causes are all there like being over-weight, lack of exercise bla bla. And your body's normal ability to regulate blood sugar keeps on deteriorating ultimately leading to a point when the alpha-glucidase alone will not be sufficient. So when pre-diabetes is treated like diabetes, it can lead to actual diabetes. This is because here the focus should not be on lowering blood glucose levels or "treating" the condition but REVERSING it. In other words the goal should be to transform the body back to the point where it can naturally process the foods while keeping the blood glucose levels and HbA1C levels in normal range. All this without the help of any drugs or special diet or aids. And for this the usual solutions are already well known: weight-loss, exercise etc.

    The moral of the story is that if you are pre-diabetic, you can keep yourself happy by eating almonds, vinegar or psyllium with meals to "show" you that your post-prandial glucose levels are in range. This can be done by eating a low-carn diet or taking diabetes drugs. But if keep the same weight, continue the same eating habbits, and do no exercise then you are possibly doing nothing to prevent a preventable disease.

  • KDL

    12/12/2010 9:50:40 PM |

    I have a 16 year old daughter who HBA1c is 11.7 (yes very high).  I have been working with her especialist to bring it down.  The problem is her daily readings are normal for a type 1 diabetic. I know the monitors can be cheated however I am pretty confident that most of the time she does the right thing.  I also know that sometimes she does not.  However I am wondering if there are any other things that can cause this annomoly?

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Lipoprotein(a)--neglected and unappreciated

Lipoprotein(a)--neglected and unappreciated


Lipoprotein(a), or just Lp(a) to its close friends and neighbors, is among the most underappreciated and neglected of causes of coronary plaque. It's the Rodney Dangerfield of lipoproteins.

Lp(a) rarely gets diagnosed before people come to my office. They've often been through the ringer: doctors have thrown their hands up in frustration because of poor response to "standard" treatment (AKA statin drugs); the patient doesn't understand why they might be thin and active yet have the high blood pressure of someone 70 lbs heavier; they have heart disease despite wonderful cholesterol values.

One blood test and the answer becomes clear: They have Lp(a). It explains all these phenomena.

They why don't more physicians order this simple test? Why don't we hear more about this prevalent (1 in 5 people with coronary plaque have it) genetic pattern that accelerates risk for heart disease?

There are a number of reasons. But I believe the most powerful reason is simply that there is no big revenue-generating drug to treat it. Statins reduce LDL cholesterol to the tune of $27 billion dollars a year (2007 revenue). There's no such blockbuster for Lp(a). Of course, Niaspan represents the relatively anemic attempt to commercialize a pharmaceutical treatment for Lp(a), but side-effects and the lack of FDA trials for the Lp(a)-reducing indication have stalled its commercial success. (Efforts to block the flush with various products, by the way, may re-invigorate niacin as a pharmaceutical agent. The drug companies smell money here.)

Another reason for Lp(a)'s unpopularity: Though there are mounds of data that document--without question--that Lp(a) is an important risk for coronary disease and other forms of atherosclerotic disease, we lack treatment trials. For instance, niacin vs. placebo for 5 years, then count the number of heart attacks and deaths. We have numerous, repetitive, overlapping, redundant trials with statins adhering to this design. We have none for niacin and the treatment of Lp(a).

Niacin is also a pain in the neck for your doctor. He/she rapidly tires of the calls about the crazy and disconcerting flushing with niacin. Most are unaware that proper hydration reduces or eliminates the flush for the majority of people. It takes too much time and energy to educate people. (By the way, prescription Niaspan makes no mention of purposeful hydration. They only suggest the nonsensical "Take with a low-fat snack," i.e., snacks that actually counter the therpaeutic effects of niacin. What they should be saying is "take with a high-fat snack" like raw almonds, foods that facilatate the benefits of niacin.)

Should someone concoct a successful pharmaceutical treatment for Lp(a), it will make the news, headlines in health magazines and health sections of the newspaper will blare about how important Lp(a) is. Yet it has been there all along, frustrating people and their physicians.

In the Track Your Plaque experience, Lp(a) clearly 1) correlates with heart scan scores, 2) correlates with progression of heart scan scores without treatment, and 3) poses special challenges for treatment. Interestingly, some of our biggest failures have been with Lp(a), as well as some of our biggest successes. (Our current record holder for the largest percentage reduction in heart scan score has Lp(a).)

If you have coronary plaque, or if there is family risk of heart disease, then Lp(a), in my view, is an absolutely essential factor to test for. Yes, treatment poses challenges. But once you know who your enemy is, then you can focus your efforts on it. Not knowing whether or not you have it leaves your efforts unfocused and generally flawed.

Track Your Plaque Members, be sure to read our in-depth Special Report, Unique Treatments for Lipoprotein(a) Reduction.



Copyright 2008 William Davvis, MD

Comments (2) -

  • Anonymous

    3/9/2008 6:36:00 PM |

    Alka-Seltzer [325 ASA, aqeous] after applesauce [3 TBS].
    High-Fiber snack plus an ASA that won`t be forgotten: It`s in the water you need to wash down the niacin, and the funny taste helps remind you:
    90% compliance if adhered to.
    Not usually required chronically,.. most flushing is "tachyphylactic".
    castelli et al An Interview with the Editor, Am J Cardiol 2005

  • buy jeans

    11/2/2010 8:53:49 PM |

    Should someone concoct a successful pharmaceutical treatment for Lp(a), it will make the news, headlines in health magazines and health sections of the newspaper will blare about how important Lp(a) is. Yet it has been there all along, frustrating people and their physicians.

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