What is a truly normal blood sugar profile for a non-diabetic healthy, non-obese individual? I know the numbers for the preprandial blood sugar (70-90 mg/dl [3.9-5.0 mmol/L]). What I would like to know is some more about the effects of the phase I insulin secretion. Is it true that a truly normal blood sugar profile rarely goes above 120 mg/dl [6.7 mmol/L] and returns to baseline within at most an hour after peaking?

Why are diabetics (missing the phase I response in most cases) advised to eat a “normal” (rice, bread,…) diet, when they almost surely reach the 180-200 postprandial level even with injected insulin? Are postprandial blood sugars in this range dangerous in the long term?

If possible it would be nice if you could provide some references to the medical literature concerning normal blood sugar profiles.

Published figures for normal fasting blood sugar levels do vary slightly with the laboratory depending on whether the report is for serum or whole blood, on the average delay before the sample is entered into the process and on idiosyncrasies in the instrumentation. In general though a figure of 70 to 95 mg/dl would be typical; but you’ll find a slightly wider range if you look in Normal Regulation of Blood Glucose at the EndocrineWeb.com web site.

The normal response to a load depends of course on the nature of the carbohydrate; but in a standardised glucose tolerance test the peak would be somewhere between 30 and 60 minutes and the ultimate return to fasting levels nearer two hours after the peak. The assay is such a common one that there is really no literature on what is strictly normal and I think that your best reference figures for this would be from your nearest hospital laboratory which nowadays express standards in terms of 95% confidence limits or the mean +/- 2 standard deviations. You have to remember too that not all of these samples would have been normal.

For diabetics the overall efficacy of their blood sugar control and vulnerability to complications is usually expressed by the Hemoglobin A1c level; but increasingly and for subjects who are on a NovoLog or Humalog/Glargine regimen with the short acting insulin given immediately after the meal with the dose calibrated to the pre-meal blood sugar and the ‘carbs’ actually consumed it has become common, at least occasionally, to also check the two hour post prandial glucose level. If this is consistently above 200mg/dl then the insulin dose or the ‘carbs’ eaten can be adjusted in the expectation of even better control.

DOB