If you have diabetes or prediabetes and are at risk of developing diabetes, you may have heard your doctor discussing your ‘HbA1c’ levels – or even just your ‘A1C’ levels. But what exactly are those?
What is HbA1c?
HbA1c is a variety of haemoglobin – the component of red blood cells responsible for circulating oxygen around our bodies. Specifically, HbA1c is ‘glycated’ haemoglobin, meaning it has chemically bonded to glucose molecules.
This chemical bonding – or glycation – occurs when blood glucose reaches a particular level over an extended period of time. The principal cause of such glucose build-up is insulin resistance which can lead to diabetes.
We’ve all heard the word ‘diabetes’, but the specifics of this all too common disorder can be hazy. Diabetes affects the metabolisation of glucose, a simple sugar which serves as a fundamental source of energy for the human body. The metabolisation of glucose is controlled by a hormone called insulin. There are two circumstances in which this process can malfunction:
- If the pancreas fails to produce sufficient insulin, not enough glucose will be metabolised and it will therefore accumulate in the bloodstream.
- If a person’s body becomes increasingly resistant to insulin over time, insufficient glucose will be metabolised and it will, again, accumulate in the bloodstream.
The first situation is called Type 1 diabetes. Typically this is a lifelong disorder which first appears in childhood. It is treated by daily insulin injections.
The second situation, dubbed Type 2 diabetes, can develop if an individual eats an unhealthy diet containing high quantities of sugar and carbohydrate-rich foods for an extended period of time. This will stimulate the production of high levels of insulin which may have less and less effect over time. Type 2 diabetes is an increasingly prevalent problem in the modern western world. If doctors detect the development of insulin resistance, they diagnose the patient with so-called ‘prediabetes’.
Since a build-up of glucose in the bloodstream leads to the formation of HbA1c via glycation, blood tests which detect its presence can be used to help diagnose a patient with diabetes or prediabetes.
What are healthy HbA1c levels?
Different metrics are used to measure HBA1c levels. You may see them quoted as a percentage for example, but mmol/mol or millimoles per mol has become the international standard. A mole or mol is a chemical unit used to indicate levels of a particular substance.
Years of research and testing suggest that a normal HbA1c level is 20 – 38 mmol/mol, indicating that the person has no current risk of developing diabetes.
What are the effects of HbA1c if levels are too high or too low?
As we saw above, high levels of HbA1c rise in parallel with abnormally high blood levels of glucose.
If not properly treated, diabetes can cause serious health complications. These include:
- Nerve damage
- Impaired vision
- Impaired hearing
- Kidney disease
- Heart disease
Glycated haemoglobin levels can be affected by more than just diet. Stress, medication, illness, and lifestyle can all have an impact as well.
Unusually low levels of HbA1c are less common but when identified, they may indicate lifestyle factors or conditions that affect blood cell count. These include:
- An overly restrictive diet
- Excessive use of antibiotics and some other drugs
- Liver disease
- Recent blood loss or donation
- Genetic abnormalities
Can low or high levels of HbA1c mean you’re diabetic?
If 20 – 38 mmol/mol is a reliable HbA1c normal range, what about higher levels? Doctors believe the following HbA1c levels typically indicate the onset of health complications:
- Possible prediabetes: 39 – 46 mmol/mol
- Possible diabetes: 47 mmol/mol and upwards
However, a blood test with such a result would not normally be the sole basis for a diabetes diagnosis, a GP would also consider other factors such as lifestyle, medications and any symptoms being experienced.
How to maintain healthy HbA1c levels
Diet is key to maintaining healthy HbA1c levels. Moderate your sugar and carbohydrate intake. That’s easier said than done because many food products contain high levels – especially processed foods. Eat more fresh food and learn to read food product labels carefully: not all are clearly worded and some manufacturers use jargon to disguise the true contents of their products. And finally: don’t be afraid to explore new foods – you may be surprised by how many you grow to like.
How to test your HbA1c levels
If you have particular health concerns, your GP may refer you for testing. A small quantity of blood will be taken from your arm for laboratory analysis.
However, waiting times can sometimes be longer if you have no apparently urgent health concerns. But it’s also possible to test your HbA1c levels at home. Such tests are quick and easy to conduct. You will receive full details of your current glycated haemoglobin levels, enabling you to make positive changes to your diet and lifestyle if you need to do so.
If you do discover that you’re drifting into prediabetes, make sure you’re tested regularly – at least once a year and ideally once every few months. This will ensure you catch any trends as they develop, keeping you in control of your health.