Oral Glucose Tolerance Test (OGTT)
The OGTT assesses first and second-stage insulin responses to glucose. It involves fasting and then consuming a 75-gram glucose solution. Blood sugar is tested one and two hours later.
If your blood sugar exceeds 140 mg/dL after two hours, you’re classified as pre-diabetic; if it exceeds 199 mg/dL, you have diabetes.
The Quandary: These numerical cutoffs may seem arbitrary, with one point below the pre-diabetic limit deeming you “normal.” In reality, diabetes is a process with incremental changes, emphasizing the importance of early intervention.
Artificial Nature: Additionally, the OGTT employs an artificial, high-glucose solution that doesn’t resemble real-life dietary choices.
Hemoglobin A1c (A1c)
A1c measures how glucose bonds to hemoglobin in red blood cells, indicating average blood sugar over the past three months.
The standard “normal” range is between 4% and 6%, with 5.7% often being the cutoff.
The A1c Caveat: While A1c has gained popularity due to its cost-effectiveness, it’s not foolproof. It can be skewed by conditions such as anemia, leading to falsely low A1c levels. Dehydration can produce falsely high A1c results (2).
The Flaws in Traditional Blood Sugar Measures
The conventional norms for these blood sugar markers have faced criticism within the functional and integrative medicine community.
- Questionable Thresholds: The cutoff values for diabetes and pre-diabetes have evolved over the years, leading to debates about when to intervene. Early intervention, particularly in the pre-diabetic stage, is often deemed more effective by functional medicine. While elevated blood sugar levels may be considered common, they are not necessarily normal.
- The OGTT Dilemma: The OGTT is criticized for its artificial nature and the abrupt blood sugar swings it induces, making it an inadequate representation of real-life glucose responses to food.
- A1c Inaccuracy: The A1c test’s reliance on hemoglobin levels makes it vulnerable to conditions like anemia, dehydration, and how long blood cells live in different people, leading to potential misinterpretations of blood sugar status (3).
Why HbA1c is Not Always A Reliable Marker of Blood Sugar Levels
While HbA1c is a popular blood sugar level test, it has its limitations. The test can be influenced by several factors such as age, anemia, hemoglobin abnormalities, kidney dysfunction, and thyroid disorders (4).
Results from the HbA1c test are also based on the assumption that red blood cells live for an average of 3 months or 120 days in the body. However, blood cells can live for a range of time in different people—anywhere from 81 days in diabetics, to as long as 146 days in people without diabetes (5). This study also found that, on average, red blood cell life span decreased by about 7 days for every 1.0% increase in glycosylated hemoglobin (red blood cells with glucose stuck to them).
This means that hemoglobin could have a longer lifespan in people with normal blood sugar, giving it more time to accumulate sugar and then artificially increase the A1c result.
HbA1c also doesn’t indicate the daily fluctuations in blood sugar levels within a day or the timing of high glucose levels. It’s for these reasons that functional medicine practitioners recommend other biomarker tests such as fasting and post-prandial glucose and continuous glucose monitoring to track blood sugar fluctuations better.
Recommendations According to Functional Medicine
Functional medicine emphasizes the importance of maintaining healthy blood sugar levels to promote overall health and longevity.
One recommendation is following a healthy diet consisting of low-glycemic-index foods. These foods are low in sugar, starch, and carbohydrates which lead to a gradual increase in blood sugar levels. Functional medicine also recommends increasing fiber intake to moderate glucose levels and improve insulin sensitivity.
Physical activity, stress-management techniques, and supplements like magnesium or chromium are also helpful in maintaining healthy blood sugar levels.
In the holistic health model, we emphasize personalized assessments, considering not just one but a range of markers to evaluate your blood sugar health.
We recommend more comprehensive panels that may go beyond fasting blood glucose and A1c. This allows for a more individualized approach to maintaining healthy blood sugar levels.
To Wrap It Up
The common norms in blood sugar measurement, while widely accepted, have their flaws. The emphasis in functional medicine is on early intervention, personalization, and the recognition that “common” doesn’t always equate to “normal.” By considering additional markers and employing a proactive approach to blood sugar management, we aim to help individuals maintain their health and well-being more effectively.
If you’re looking to take a more proactive approach to your blood sugar health, consider consulting a functional medicine practitioner at CentreSpringMD who can provide a more comprehensive assessment and personalized recommendations based on your unique needs.