What your doctor doesn't know about glucose testing.

Blood sugar management is important for preventing everything from hypoglycemia to full blown diabetes. However, monitoring blood glucose is rarely as straightforward as it seems.

In this article we’ll discuss the current gold standard for measuring a person’s blood sugar. We’ll share some problems with the most popular tests. And we’ll review the best ways to interpret your results. (Even if your doctor doesn’t know how).

[Note: We’ve also prepared an audio recording of this article for you to listen to. So, if you’d rather listen to the piece, click here.]

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Homeostasis is a fancy scientific word for “body balance”. Essentially, our bodies must keep internal levels of thousands of chemicals in check. Or else health can go awry.

One of the most important homeostatic systems in our body is our blood sugar management system.

When blood sugar is kept at a healthy range, we feel healthy, strong, energetic. On the other hand, unbalanced blood sugars put us at risk for problems ranging from reactive hypoglycemia to insulin resistance to full blown diabetes.

But estimating blood sugar levels can be tricky.

First, these levels change throughout the day, and with meals and exercise. So, unless you’re monitoring blood sugar levels continuously, every second of every day, it’s hard to get a complete picture of your glucose health.

Second, the convenient glucose meters that many Type 1 diabetics use only give us a snapshot instead of a movie. They don’t show us how patients regulate blood sugars over time. And that may be the most important information of all when it comes to disease prevention.

That’s why doctors and scientists have become obsessed with finding a test that measures blood glucose balance across days, weeks, or months. In other words, a test that will tell us about mid-term and long-term glucose health vs. a snapshot of what’s happening right now, at this minute.

While no one has found the perfect test yet, there are two tests often used in medical practice today. These are jockeying for top position when it comes to measuring glucose health.

These tests measure:

glycated hemoglobin or hemoglobin A1c

fructosamine

Both tests are very interesting in that they give a clearer understanding of glucose levels over time. Yet both have drawbacks that can get in the way of accurate diagnosis. Especially in healthy folks.

Let’s take a closer look.

Glycated hemoglobin, or hemoglobin A1c

The glycated hemoglobin, or hemoglobin A1c test, allows doctors to estimate a patient’s average blood sugar levels across a period of several months.

No wonder A1c is often considered the gold standard for evaluating glucose levels. More and more healthcare professionals, both conventional and alternative, are basing their diagnosis and treatment on the information they get from it.

How the hemoglobin A1c test works

Hemoglobin is a protein found inside your red blood cells. It carries oxygen from your lungs to all the cells of your body.

Since red blood cells are always forming and dying, their typical life span is about 3 months.

This is important because, when you eat, glucose (sugar) enters your red blood cells and links up (glycates) with the molecules of hemoglobin found inside.

In the end, the more glucose in your blood, the more hemoglobin gets glycated. And vice versa.

So by measuring the percentage of A1c in the blood, we can get an overview of our average blood glucose control for the past few months.

When A1c might not be accurate

Testing hemoglobin A1c sounds like an excellent idea — in theory. And indeed, the A1c test is very helpful for people already diagnosed with diabetes.

Chronically high A1c levels predict greater risk for certain diabetic complications, such as retinopathy (possibly leading to blindness), nephropathy (possibly leading to kidney failure), and neuropathy (e.g., problems with the nerves).

The trouble is, a couple of factors can falsely raise or decrease hemoglobin A1c, especially in healthy people.

This can confuse practitioners and patients.

Glucose regulation and A1c

First, folks with healthy blood sugar levels may have longer-lived red blood cells than those with poor glucose regulation.

The better you regulate and manage glucose, the longer your red blood cells can survive. The longer your red blood cells live, the higher your circulating hemoglobin. And if circulating hemoglobin is high, that will probably show up in the A1c blood panel.

In other words, it’s possible for your hemoglobin A1c to appear a bit high, even — or maybe especially — if your blood sugar regulation is excellent.

And the opposite can also be true.

Poor glycemic control may kill off red blood cells prematurely. This can result in less circulating hemoglobin and a lower hemoglobin A1c measurement — even if your actual glucose levels are actually on the higher side. How ironic!

If you’re feeling confused, no wonder. This is one of those situations where being especially healthy can actually interfere with accurate assessment. It’s also why scientists are looking for better tests.

How long do your red blood cells live? If longer-lived red blood cells can lead to higher hemoglobin A1c levels, despite healthy glucose levels, maybe doctors should be evaluating the lifespan and turnover of red blood cells in their patients. Here’s a calculation for doing that. It’s just an estimation, as blood chemistry calculations aren’t perfect. Still, it may give a bit of insight into your personal red blood cell lifespan and it offers food for thought. To do this calculation, you’ll need to know your reticulocyte count and your hematocrit. Reticulocytes are early red blood cells. Produced in the bone marrow, they’re released into circulation as reticulocytes, and in a few days transform into fully mature red blood cells. Reticulocytes can be used as a marker of red blood cell production. For example, in someone who is losing blood (for example, from a bleeding ulcer or heavy menstruation) or in someone with short-lived red blood cells, the reticulocyte count may be higher. This is because the body will attempt to increase blood cell production to make up for the loss. On the other hand, a low reticulocyte count can indicate that the body is generally happy with the amount of red blood cells or their lifespan, and doesn’t need to pump out as many reticulocytes. The equation for determining how long your red blood cells are surviving is: Red blood cell survival (days) = 100/[reticulocytes (percent)/reticulocyte life span (days)] Here is an example: Let’s say your reticulocyte count is 0.8% and your hematocrit is 45. Pulling from corrected reticulocyte count tables, the number for the reticulocyte life span (RLS) number would be 1.0. Thus your equation would look like this: 100/[0.8/1] = 125 days If your hemoglobin A1c number is a little higher than you’d expect given your current diet and lifestyle, and your red cell survival is longer than 120 days, your longer-lived red blood cells may be the reason.



Fat intake and A1c

Another factor that can affect hemoglobin A1c levels is the amount and type of fat you eat.

One recent study found that high saturated fat intake is associated with higher A1c levels, though the authors caution that we shouldn’t draw any absolute conclusions from their findings.

Another study showed similar correlations between fat intake and A1c levels, once again demonstrating that higher A1c levels were associated with greater saturated fat intake. Meanwhile, subjects who ate more polyunsaturated fat had lower A1c levels.

Finally, a third study suggested that hemoglobin A1c levels may be more affected by dietary saturated fat intake than by dietary carbohydrate (or sugar) intake.

In other words, the amount and type of fat you eat can influence hemoglobin A1c levels, creating falsely elevated levels that might not reflect your actual glucose management.

High protein intake and A1c

People with chronic kidney disease often have elevated hemoglobin A1c levels. We’re not sure why, but it may be because their serum urea is higher. And higher serum urea may increase glycation.

Folks who eat a high protein diet can also have high serum urea — though their levels are nowhere near as high as those with kidney disease. Sill, if urea increases glycation, it’s possible that a high protein diet could slightly increase hemoglobin A1c levels.

At this point, it’s only a theory. To my knowledge, few, if any, studies have evaluated protein intake on hemoglobin A1c levels. We’d need to do more research to know for sure. Nevertheless, it’s worth pondering.

What is urea?

Urea is a colorless, odorless solid, highly soluble in water and practically non-toxic. Our bodies use it in many processes, the most notable being nitrogen excretion.



Antioxidant supplementation and A1c

Vitamin C, vitamin E, or coenzyme Q10 may decrease hemoglobin A1c levels.

Again, we need a lot more research to confirm or disconfirm these findings but early research suggests there’s a link.

Anemia and A1c

The effects of anemia on hemoglobin A1c are mixed.

On the one hand, anything that leads to a shorter red blood cell lifespan theoretically could reduce a person’s A1c levels. So, folks with untreated B12, folic acid, hemolytic, or iron deficiency anemia might show artificially lowered A1c levels, despite their glucose levels.

On the other hand, iron deficiency anemia, in particular, can actually lead to higher levels of hemoglobin A1c. That’s because of a compound called malondialdehyde, which increases glycation.

Summary of possible interfering factors with Hemoglobin A1c levels

In the end, here’s a summary chart of the main factors that could impact A1c levels and create confusing and erroneous test results.

Potential cause Possible impact on A1c High protein diet Elevated serum urea Increased Healthy glucose levels Longer lived red blood cells Increased Iron deficiency anemia Increased glycation due to elevated malondialdehyde Increased High saturated fat intake Observation Increased Vitamin C, vitamin E, and/or CoQ10 supplementation Decreases glycation Decreased Excess red blood cell breakdown Shorter-lived red blood cells Decreased

Does this mean the hemoglobin A1c test is useless?

No. When evaluating physiology, the more data the better. As with many blood chemistry markers, the A1c test is well worth looking at. But you need to take its results in context.

If your levels appear a little higher than you expect given your current diet, lifestyle, and exercise program, maybe you and your doctor should consider whether something other than faulty glucose regulation may be at play.

For example, let’s say you’re following a Paleo-type diet with relatively high amounts of protein and saturated fat. On testing, your hemoglobin A1c levels may be a little higher than expected. This reading may overestimate your actual glucose levels over the past few months.

What about other markers of glucose health?

Doctors and researchers can also test fructosamine to evaluate glucose regulation over time.

Where the hemoglobin A1c test supposedly gives a picture of glucose levels over the past few months, fructosamine levels give information about the past two or three weeks.

How the test works

Like the hemoglobin A1c test, fructosamine testing also measures the amount of glycation. But this test considers a different protein, called albumin.

Albumin is the most abundant protein found in your blood stream. It is produced in the liver and is said to exist for approximately three weeks before being broken down.

One study suggests that fructosamine is a better indicator of carbohydrate intake than the hemoglobin A1c test.

Fructosamine testing can’t reveal as much about the possible long-term complications of diabetes as hemoglobin A1c testing. That’s one reason it’s a little less popular with doctors. Yet it’s useful in special situations, like diabetic pregnancy, or where a patient’s diabetic treatment protocol is changed very quickly.

And fructosamine testing appears to be quite accurate. Still, it’s not a perfect measure of glucose regulation. Here’s why.

When the test can go wrong

First, albumin is a negative acute phase reactant, meaning it tends to go down during periods of inflammation or infection.

Thus, people who are chronically sick often have lower albumin levels. And this may falsely lower their fructosamine readings.

(On a personal note, at least half my patients register low-normal albumin levels when they first arrive at my office. Especially the female patients.)

Dehydration can also affect fructosamine levels. This can lead to “false positive” results, showing that someone has elevated glucose when in fact, her glucose regulation is just fine. (She just needs to drink more water.)

Finally, high levels of Vitamin C and hyperthyroidism can also complicate test results.

How sweet it is

What can you make of all this?

If you’re eating right, exercising, and following a healthy lifestyle, yet your glucose markers seem out of whack, don’t assume that faulty glucose regulation is necessarily to blame.

Instead, explore with your doctor whether other factors might be affecting your readings before jumping to the conclusion that you are diabetic or pre-diabetic.

Hemoglobin A1c and fructosamine tests are clinically useful and important markers, especially for those already diagnosed with diabetes. But in healthy people, they’re far from perfect tests.

Consider them in context and you’ll gain a clearer picture of your overall health — along with a surer pathway to continued vitality.

Eat, move, and live… better.©

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References

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