What is a normal blood sugar?

We have come to confuse normal blood sugar levels with commonly seen blood sugar levels. Just because something is common, doesn’t mean it’s normal. It’s now becoming common for kids to be overweight and diabetic because they eat vast quantities of refined flour, high-fructose corn syrup and industrial seed oils. Yet I don’t think anyone would agree that this is ‘normal’ for kids, or even adults. In the same way, the guidelines that have been set for normal blood sugar may be common, but they’re certainly not normal. It’s common but not normal for people to develop diabetic complications like neuropathy, retinopathy and cardiovascular disease as they age.

Three ways blood sugar is measured

1. Fasting blood glucose The fasting blood glucose (FBG) test measures the concentration of glucose in the blood after an 8-12 hour fast. It only tells us how blood sugar behaves in a fasting state. It tells us very little about how your blood sugar responds to the food you eat.The upward limit of normal blood sugar at 99 mg/dL. Anything above that – but below 126 mg/dL – is considered “pre-diabetic”, or “impaired glucose tolerance” (IGT).  According to glucose monitoring studies of healthy people, a normal fasting blood sugar is 83 mg/dL or less. Many normal people have fasting blood sugar in the mid-to-high 70s.While most doctors will tell you that anything under 100 mg/dL is normal, it may not be. In one study, people with FBG levels above 95 had more than 3x the risk of developing future diabetes than people with FBG levels below 90.
2. Oral glucose tolerance test (OGTT) The OGTT measures first and second stage insulin response to glucose. You fast and then you’re given 75 grams of glucose dissolved in water. Blood sugar is measured one and two hours after.If your blood sugar is >140 mg/dL two hours later, you have pre-diabetes.If it’s >199 mg/dL two hours later, you’ve got full-blown diabetes. If your result is 139 mg/dL – just one point below the pre-diabetic cut-off – you’ll be considered “normal”.
3. Hemoglobin A1c Hemoglobin A1c, has become more popular amongst practitioners in the past decade because it’s significantly cheaper than the OGTT test. This test is a rough measure of average blood sugar over the previous three months. A truly normal A1c is between 4.6% and 5.3%.The problem with the A1c test is that any condition that changes hemoglobin levels will skew the results. Anaemia is one such condition, and sub-clinical anaemia is incredibly common. It is important to never use any single marker alone to determine whether someone has a blood sugar issue.

If someone has a few post-meal spikes and all other markers or normal, it should not be a concern. If their fasting BG, A1c and fructosamine are all elevated, and they’re having spikes, then this tells a different story and further investigation is required. If post-meal blood sugars do rise above 140 mg/dL and stay there for a significant period of time, the consequences are severe. Prolonged exposure to blood sugars above 140 mg/dL causes irreversible damage to the insulin producing beta cells and nerve damage. Also cancer rates increase as post-meal blood sugars rise above 160 mg/dL.

What does it all mean?

It means that glucose levels depend highly on context and whether all markers are elevated, or just a few of them. If you’re interested in health and longevity – instead of just slowing the onset of serious disease by a few years – you might consider shooting for these targets. But remember to interpret the numbers together.

Marker	Ideal
Fasting blood glucose (mg/dL)	<86*
OGGT / post-meal (mg/dL after 2 hours)	<120
Hemoglobin A1c (%)	<5.3

It is important to remember that fasting blood glucose and A1 are not often reliable for predicting diabetes or CVD risk. Post-meal blood sugars are a more accurate marker for this purpose, and this can be done cheaply, safely and conveniently at home! More information to come!

Stay tuned for more to come…

Check out the Diabesity story so far and catch up on each instalment below

See also Part 1 of our series The Modern Day Health Epidemic that you should know about See also Part 2 of our series Diabesity: Myths that kep you sick See also Part 3 of our series Diabesity and Inflammation See also Part 4 of our series Diabesity: How come I’ve got Type 2 Diabetes? I’m not fat!!! See also Part 5 of our series Diabesity: Not all Diabetics are Obese See also Part 6 of our series Diabesity: How modern lifestyles affects your metabolism See also Part 7 of our series Diabesity: The major triggers – What you need to know See also Part 8 of our series Ten ways stress can cause Diabesity See also Part 9 of our series Diabesity: A magic ingredient for weight loss? – A healthy gut See also Part 10 of our series Diabesity: Toxic Overload