According to continuous monitoring of glucose in healthy people, normal blood sugar levels at the post are 83 mg/dL or less. Many normal people have normal blood sugar levels at the post in the middle and early 70's, to these conclusions came Mr. Denis.
Although most doctors will tell you that anything below 100 mg/dL is normal, it may not be so. In this study, people with FBS above 95 were more than 3 times more likely to develop diabetes in the future than people with FBH below 90. This study showed a gradual increase in the risk of heart disease in men with FBH above 85 mg/dL, compared to men with FBH 81 mg/dL and below.
Much more important than a single measurement of blood glucose FBS on an empty stomach, the number of hours per day we spend in the blood exceeds the level known to cause complications, and is approximately 140 mg/dL (7.7 mmol/l). I will tell you more about this in the OGGT section.
One of the caveats here is that very low carbohydrate diets will produce elevated blood glucose levels FBS on an empty stomach. Why is that? Because low-carbohydrate diets cause insulin resistance. Carbohydrate restriction leads to a natural reduction in insulin levels, which in turn activates hormone-sensitive lipase. The fatty tissue then breaks down and un-esterified fatty acids ("free fatty acids" or NEFA) are released into the bloodstream. These NEFAs are captured by the muscles that use them as fuel. And since the muscle's fuel needs are met, insulin sensitivity is reduced. You can read more about this in Hyperlipid.
Thus, if you eat a low-carbohydrate diet and have a borderline high FBG (i.e. 90-105), it may not be a concern. Yours after eating blood sugar and A1c levels are more important.
But while A1c is a good way to measure blood sugar in extensive demographic research, it is not as accurate for individuals. A1c of 5.1% corresponds to an average blood sugar level of about 100 mg/dL. But A1c results for some people are always slightly higher than their FBG and CGTT predictions, and for others they are always slightly lower.
This is probably due to the fact that several factors may affect erythrocytes. Remember that A1c is a measure of how much hemoglobin in erythrocytes is associated (glycated) with glucose. Anything that affects erythrocytes and hemoglobin - such as anemia, dehydration and genetic disorders - distorts the results of A1c.
Several studies show that A1c levels below the diabetic range are associated with cardiovascular disease. This study found that A1c levels below 5% had the lowest level of cardiovascular disease (CVD) and that an increase of 1% (to 6%) significantly increased the risk of CVD. Another study showed an even closer correlation between A1c and CVD, indicating a linear increase in CVD as A1c rose above 4.6%, a level that corresponds to fast blood glucose of only 86 mg/dL. Finally, this study showed that the risk of heart disease in people without diabetes doubles by every percentage point, increasing above 4.6%.
The studies also consistently show that A1c levels considered 'normal' by ADA cannot predict future diabetes," says Slinkin. The study showed that using the A1c ADA criteria of 6% as 'normal', 70% of diabetics, 71-84% for dysglycemia and 82-94% for pre-diabetes are missed. How does it feel to be accurate?