The impact of sugar on our health is well-known, from its role in diabetes to heart disease. But measuring blood sugar can be tricky—daily levels fluctuate, making it challenging to gauge overall glucose control. HbA1c levels provide a snapshot of your average blood sugar over the past 2-3 months, offering a clearer picture of your long-term glucose management.
At Superpower, we believe that the current conventional range for HbA1c is too permissive and misses a window of opportunity for proactive intervention. By leveraging available research, we've identified an optimal HbA1c range that aims to optimize health outcomes. This approach allows us to address potential issues early, helping you achieve and maintain peak health rather than simply avoiding disease.
Key Points
- "Normal" isn't OPTIMAL: Studies show increased risks of heart disease, dementia, and early death at HbA1c levels currently considered "normal" - below the diabetes threshold.
- Silent Glycation Burden: Every 0.1% increase in HbA1c above 5.5% is linked to higher glycation damage - the stealthy buildup of tissue injury over decades.
- Re-defining “Optimal”: Research suggests that a lower optimal HbA1c level may maximize metabolic fitness, improve long-term brain health, and increase healthspan.
- Conventional Range: < 5.7%
- Optimal Range: 4.5-5.25%
What is HbA1c?
HbA1c, or glycated hemoglobin, measures long-term blood sugar levels. Hemoglobin (HbA) in red blood cells carries oxygen throughout the body. When sugars like glucose stick to hemoglobin, they form glycated hemoglobin (HbA1c), which is less efficient at delivering oxygen. This process occurs gradually over the 120-day lifespan of red blood cells. Thus, the HbA1c test provides an average measure of blood glucose levels over the past two to three months, offering a more comprehensive view than daily blood sugar tests.
HbA1c is important because it shows how well your body manages blood sugar over time. Unlike daily blood sugar readings that fluctuate due to diet, stress, or activity, HbA1c levels remain stable, providing a reliable indicator of long-term glucose control. This makes HbA1c a critical measure for understanding overall metabolic health and identifying potential risks early, helping you and your healthcare provider make informed decisions about lifestyle and health interventions.
Why should you care about HbA1c levels?
HbA1c has emerged as a critical biomarker for metabolic health and longevity, extending far beyond its traditional role in diabetes management. Its significance lies in predicting future health risks, with research showing that even small elevations within the "normal" range can significantly increase risks of cardiovascular disease, kidney problems, and cognitive decline.
Studies reveal that individuals with HbA1c levels of 5.7-6.4% (often labeled "prediabetic") face 30-40% higher rates of cardiovascular events and mortality compared to those under 5.7% [1-3]. HbA1c is also an independent predictor of non-fatal cardiovascular disease in non-diabetic populations [4]. Moreover, non-diabetic individuals with HbA1c above 5.6% show a 28% higher risk of all-cause mortality over a decade [5-7].
Crucially, every 0.1% increase in HbA1c above 5.5-5.7% is associated with increased risks of heart disease, stroke, kidney disease, dementia, cancer, and premature death [3]. This emphasizes the importance of achieving optimal HbA1c levels, not just staying within the conventional "normal" range.HbA1c also reflects the body's glycation burden. As glucose binds to proteins and lipids, it forms advanced glycation end-products (AGEs), contributing to oxidative stress, inflammation, and cumulative tissue damage. Monitoring HbA1c tracks this long-term process, crucial in aging and chronic disease development.
For those with erratic schedules or difficulty with daily glucose monitoring, HbA1c offers a reliable proxy for long-term glycemic control. Ultimately, HbA1c provides a comprehensive window into metabolic health, offering insights into cardiovascular health, longevity, and overall metabolic function beyond diabetes risk.
What is the conventional reference range?
The American Diabetes Association (ADA) and other medical organizations define these HbA1c ranges:
- Normal: < 5.7%
- Prediabetes: 5.7% - 6.4%
- Diabetes: ≥ 6.5%
These ranges diagnose diabetes and identify risk but may not reflect optimal levels for health and longevity.
What do high and low levels of HbA1c mean?
LOW: Low HbA1c can indicate chronic low blood sugar or increased red blood cell turnover. This may be due to blood loss, hemolysis, hemolytic anemia, or chronic kidney failure. Certain treatments and supplements can also lower HbA1c, including erythropoietin, iron, vitamin B12, folate, and high doses of vitamins C and E.
HIGH: High HbA1c typically suggests chronic high blood sugar and poorly controlled diabetes. However, other factors can also raise HbA1c levels. These include conditions that prolong red blood cell lifespan (like iron, B12, or folate deficiency anemias), genetic variants, chronic alcohol consumption, kidney disease, corticosteroid use, Cushing's syndrome, high triglycerides, and atherosclerosis.
Why is the Conventional Range for HbA1c Problematic?
The conventional HbA1c range, used to diagnose diabetes and prediabetes, falls short when it comes to promoting optimal health and longevity [8, 9]. This approach is reactive rather than proactive, focusing on identifying disease instead of preventing it and optimizing metabolic health.
Here's the issue: HbA1c levels between 5.7-6.4%, often considered "prediabetic," don't always accurately reflect a person's true metabolic health. These levels can misclassify glycemic status when compared to more comprehensive tests like oral glucose tolerance tests (OGTT) [10]. This means we might be missing important metabolic risks in people who appear "normal" by conventional standards.
Moreover, HbA1c levels don't always capture the full picture of insulin resistance and β-cell function in people without diabetes [11]. This underscores a crucial point: current ranges are more focused on diagnosing diabetes than on optimizing overall health.
When blood sugar and HbA1c levels rise, even within the "normal" range, they can trigger a cascade of harmful effects in the body:
- Oxidative stress increases as higher glucose levels lead to more free radical production, overwhelming our natural antioxidant defenses [12, 13].
- Our immune system can become compromised, with elevated glucose impairing white blood cell function and increasing inflammation [14, 15].
- Lipid metabolism becomes impaired due to insulin resistance associated with higher HbA1c levels [16, 17].
Interestingly, HbA1c levels of 5.7%-6.4% don't reliably identify individuals with impaired insulin action or secretion. Higher HbA1c is also linked to endothelial dysfunction, which can lead to atherosclerosis and vascular complications [18].
By the time HbA1c reaches prediabetic or diabetic ranges, significant metabolic damage may have already occurred [19]. This delay reduces our chances of achieving optimal health through early, proactive intervention.
Research suggests that aiming for HbA1c levels below the conventional “pre-diabetic” threshold may have significant health benefits.
What is the Superpower Optimal Range for HbA1c?
The optimal range for HbA1c for promoting overall health and longevity is still a topic of ongoing research and debate. At Superpower, we recommend an optimal HbA1c range substantially lower than the conventional "non-diabetic" range is better for overall wellbeing.
Superpower optimal range: 4.5% - 5.25%.
This lower range aims to minimize the risk of chronic complications associated with even moderately elevated blood levels sugar levels over time.
Supporting Evidence from Research Studies
Research increasingly supports the potential benefits of maintaining HbA1c levels between 4.5% and 5.25% - lower than the conventional “pre-diabetic” threshold. This lower range is associated with optimal physiological function and provides numerous health advantages across metabolic and overall health.
Cardiovascular health is significantly impacted by HbA1c levels. Large-scale studies have found that non-diabetic adults with HbA1c levels below 5.0% had the lowest rates of cardiovascular events and death, with risk increasing significantly for those above 5.5% [20, 21]
The benefits of lower HbA1c extend beyond heart health to overall mortality. Meta-analyses and prospective studies have revealed that mortality risk from all causes was lowest when HbA1c levels were between 4.5% and 5.0. The risk increased progressively above this range, even within levels traditionally considered “normal” [22, 23].
Cognitive function and brain health also appear to benefit from lower HbA1c levels. Research has demonstrated that higher HbA1c levels, even within the normal range of 5.0-5.6%, were associated with lower cognitive performance and brain volume. Studies have also linked higher HbA1c to poorer performance in memory and executive function tasks [23-25].
Lower HbA1c levels are also associated with reduced inflammation and better metabolic health. Studies have found an inverse relationship between HbA1c and inflammatory markers like C-reactive protein (CRP), indicating a protective effect against inflammatory diseases [26].
Furthermore, maintaining HbA1c in the 4.5% - 5.25% range appears to offer protection against microvascular complications and diabetes progression. Research has shown that the risk of diabetic retinopathy began to increase at HbA1c levels as low as 5.5%, and individuals with HbA1c levels below 5.3% had significantly better insulin sensitivity [27, 28]. Studies have also found a substantially reduced risk of developing type 2 diabetes in individuals with HbA1c levels below 5.0% [29].
This evidence suggests that aiming for a lower HbA1c range may promote optimal health beyond merely preventing diabetes and emphazes the importance of early intervention and lifestyle management for long-term metabolic health.
The Key Takeaway
Research suggests that aiming for an HbA1c between 4.5-5.25% could offer significant benefits. This lower range isn't just about avoiding diabetes; it's about optimizing your overall health and longevity. At these lower levels, you're potentially reducing the long-term damage caused by excess sugar binding to your cells. This could translate to a lower risk of heart disease, better cognitive function, and even a longer life span.
At Superpower, we don't wait for pre-diabetes to set in before taking action. Our aim is to proactively manage your HbA1c levels to actively protect your body from the effects of elevated blood sugar and its downstream consequences.
