You’ve probably seen people online talking about continuous glucose monitors (CGMs). Perhaps you’ve seen the adverts for the Zoe programme. Or else you might well have spotted people wearing a little white disk on their upper arm and wondered, what’s that all about? Want to know how all of this relates to you and, of course, whether you should invest in one? Read on.
What does a CGM do
A CGM is a wearable device that takes a measurement of blood sugar from interstitial fluid – the fluid between cells – every five minutes. This allows the device to provide real-time data on fluctuations in your blood sugar. Understanding fluctuations in blood sugar level is important to general health.
People are using these devices to understand what their blood sugar levels are. For some, this is a medical necessity. They have been told they have diabetes, for example, and want to get back in control of their glucose levels or, for type 1 diabetes, they need real-time information to work out how much insulin they need to dose. Since very high sugars (hyperglycemia) are dangerous to the body and very low sugar levels (hypoglycemia) can be life-threatening, these monitors can mean the difference between life and death.
Over the last couple of years, more and more people who are simply interested in their health are also investing in CGMs. These might be people who have been told they have prediabetes and who want to reduce the risk of developing type 2 diabetes, or those who are looking for answers to why their energy is lacking, or why they’re struggling to lose weight, or possibly people who love getting data and insights on what their body is doing and how well it is functioning.
How do CGMs Work
When you see someone wearing a little disc attached to their upper arm, chances are, it’s a continuous glucose monitor (CGM) or, more specifically, a related device called a flash glucose monitor (FGM). The two terms are used interchangeably although there are some very subtle differences in the way they fetch their readings.
Both devices are designed to monitor blood glucose levels. A CGM continuously tracks glucose levels in real-time and provides continuous updates to the user throughout the day and night. It can also talk to insulin pumps.
In contrast, a flash glucose monitor (like the FreeStyle Libre), takes some automatic readings but it also requires the user to scan the sensor worn on the skin with a reader or a smartphone app to get the glucose readings. The readings are stored on the sensor and can be reviewed later to get a general idea of glucose trends over time. It can only store eight hours of data, so users typically have to ensure they scan before bed and shortly after they get up to make sure readings have been taken and there are no gaps in data.
We’d expect morning fasting glucose levels to be between 4 mmol/L and 5.4mmol/L (72 to 99 mg/dL) for non-diabetics. 5.5 to 6.9 mmol/L (100 to 125 mg/dL) may be indicative of prediabetes and a reading of 7.0 mmol/L or more (126 mg/dL or more) may suggest diabetes.
How Can a CGM Help stabalise Blood Sugar Levels
Large fluctuations in blood sugar levels can lead to hormonal imbalances which are linked to dozens of symptoms and chronic illnesses, even for people without diabetes. Since it’s not just what you eat that can affect blood sugar levels, CGMs offer a really great way to discover what food and lifestyle habits serve your body best and which might be best to avoid.
When you start glucose monitoring, you may see some peaks and falls in your data. This is nothing to be alarmed about as there are a few short-term factors that can affect glucose such as sensor warm-up, dehydration/sweating and exercise. But the key factors to focus on that cause glucose to rise and fall are food, exercise, sleep, and stress.
When it comes to food carbs get broken down into their simplest form: glucose, a simple sugar. Glucose is shunted into muscles and cells by insulin, a hormone, to produce energy. Any excess glucose is stored in the liver and fat cells. While it’s normal for your glucose levels to rise and fall, it’s the big spikes and crashes that can lead to poor metabolic health.
At The Thrive Practice, we partner with Veri to help our clients understand their metabolic health. Veri is more than a CGM, their app-based platform provides the data and insights you need to stablise your blood sugar. The graphs below show what you might expect to see following meals that you eat while wearing the CGM.
The first meal (above) shows a very minimal rise in glucose, while the second meal (below) shows a steeper rise that remained within the target zone (gray dotted lines) and returned to baseline within a couple of hours. Both of these are appropriate responses. The Veri app also provides useful information about the average glucose level across the day, how much the glucose level varies across the day (glucose variability) as well as the average height of the daily glucose response curve (glucose oscillation). Letting the user know if these were optimal or not.
This final image, below, shows the kind of glucose response to avoid. This graph exceeded the target range (gray dotted line) and didn’t return to baseline levels after two hours. In this situation, over time low blood suagr (hypoglycaemia) may develop when eat foods that spike our blood sugar too much requiring more and more insulin to be released by the pancreas as it tries to manage and stabalise blood sugar. That can cause hypoglycaemia leading to feelings of weakness, shakiness and cravings for starches and sugars, causing us to eat another glucose spiking meal or snack. And the cycle repeats again and again. Eventually the body’s cells become resistant to insulin and conditions like typ 2 diabetes develop.
The meal scores provided by Veri are also a helpful indication of how severe your response to glucose was. Letting you know which foods it might be worth reducing or avoiding and which to keep.
Once you know how you respond to particular foods or lifestyle factors you can then make the changes your body needs to feel its best.
How Can I Get A CGM?
If you are diabetic, you might be entitled to a device on prescription in the UK. If you are simply interested in your metabolic health, you will not. You can, however, take part in the Zoe programme, which also includes a stool test, but there is often a wait of a few months before you can participate and you pay for the programme upfront, making it quite pricey. Alternatively, you can also sign up for Veri and follow a self paced programme which includes 4 sensors for 56 days of blood sugar tracking. FreeStyle Libre CGMs can be purchased directly from selected pharmacies and the manufacturer Abbott direct. Each sensor lasts 14 days and costs between £55-77 each.
At The Thrive Practice we run a 5-week online metabolic health programme that combines your data from a CGM with behaviour-change psychology and health science to guide you on your journey to better metabolic and general health – no more guessing, restriction or one-size-fits-all diets. This programme, MetaMorphosis is running live from the 15th January 2024. Are you ready to transform your health? Get started today.