CGMs

What is a CGM?

Wearable technology to monitor health is not new. In fact, eyeglasses were considered the first wearable technology. Today, wearables are usually small electronic devices, equipped with wireless communications, which are able to track a variety of physiological functions, and then report them to apps where different parameters can be measured over time. The benefit or draw of wearables is that they’re able to capture rich information which may help to personalize health strategies and goals for individual needs.

Glucose monitoring, or continuous glucose monitoring (CGM), is a tool that exists for people with diabetes. It helps to measure blood glucose levels over a period of time, when wearing the device. These devices have become incredibly popular in the non-diabetic population to track how foods consumed affect blood sugar and help people to pick the right foods for their metabolism. Companies that market these devices suggest that by learning what foods spike blood sugar, individuals can decrease fat storage, lose weight, and achieve better health.

These devices are invasive, meaning they utilize a small needle, usually placed in the arm or abdomen, to measure blood glucose. Once the device is placed on the skin however, most report that they do not notice it. There are companies working on non-invasive versions of this technology.

What’s interesting is that the blood glucose monitoring device market is expected to be worth around US$ 23.5 billion by 2030 and is expected to grow at a compound annual growth rate of 7.1% from 2022 to 2030. The US leads the market and the self-monitoring blood glucose devices accounted for the largest share of revenue. Companies are reaping huge profits from these devices.

Why are they so popular?

Continually monitoring blood glucose for someone with diabetes, especially someone who requires insulin, can be lifesaving. It can tell them when they’re blood sugar is too high or too low in real time and give them information on their blood sugar control over a period of time. Parents of young children who have Type I diabetes can also see the data via the apps that are available, which helps them to participate in their child’s diabetes management, ultimately contributing to their health. What about for people that are not diabetic?

The companies who market CGMs claim that by using these devices people can monitor what foods spike their blood sugar. Marketers state that when blood sugar spikes is when glucose is stored as fat, which will contribute to weight gain. Through monitoring, these companies claim that people can learn how to keep their blood sugar in a healthy range to perform their best, improve their health, and prevent diabetes by changing what and/or when they eat.

Other reasons why they’re so popular include: detecting pre-diabetes, providing an illusion of control, and helping to satisfy one’s curiosity.

Is a CGM worth it?

While blood sugar monitoring for people with diabetes offers unparalleled benefits, there is no good quality data to support the use of these devices in non-diabetic people.

In one study, for people who did not have diabetes, about 96% of the time blood sugar levels were either normal, or nearly so, and many of the abnormal levels were considered a mistake or unable to be explained. A CGM company posted a study on their website claiming better blood glucose results among healthy consumers using their product. However, when reviewed by experts at Harvard, it was found that the study was not published in a peer-reviewed journal, lacked details to complete a critical evaluation of findings, and reviewed arbitrary blood sugar values rather than any actual associated health outcomes such as heart disease, hospitalizations, or nerve damage.

In fact, none of the health claims made about monitoring blood glucose for non-diabetics have been proven or well-studied. In addition, the ideal range of a blood sugar for someone who isn’t diabetic is actually uncertain, and highly individualized. The way a piece of bread affects one non-diabetic person may be entirely different from another, and this is normal. More goes into blood sugar variability than simply what or when something is eaten. Sleep, stress, whether someone worked out recently, supplements, medications, and medical history can all affect how a non-diabetic's blood sugar responds from a carbohydrate containing food.

In addition, CGMs may feed misinformation about carbohydrate containing foods, ultimately fueling a negative perception, and causing people to eliminate healthy carbs from their diet.

Carbohydrates already get a bad rep as it's a common thought that carbohydrates are what cause people to gain weight. In reality this is not true and carbohydrates are incredibly important for health (see the Carbohydrates Article in the Macronutrient section for more information).

One example is how carbohydrates affect the health of the gut. Carbohydrates have been shown in research to support the healthy proliferation of good gut bacteria. In other words, they support the healthy gut microbiome which is critical to overall health. On the flip side, a diet high in protein may create an environment where unhealthy gut bacteria can thrive. More and more research is linking an imbalance in healthy gut bacteria with the development of serious diseases. Therefore, carbohydrates are critical for a healthy gut and the overall health of the body and if a device is influencing the elimination of healthy carbs from the diet, that is a problem.

Bottom line

Gaining knowledge for power, or to satisfy a curiosity is interesting, however it may be a waste of time, money, and even harmful in the long run. It’s possible that these systems tell someone they are having a drop in blood sugar. In a non-diabetic person that is actually biologically insignificant information. It's a normal physiological response in the body, which likely will prompt a hunger cue for that person to go get something to eat. It could also show a blood sugar spike following a meal, which in a non-diabetic is also biologically insignificant and the body working the way it should. And it’s also possible that these systems put out false or unverifiable information, contributing to anxiety, more doctors’ visits, and even inappropriate medical treatment.

These devices are also not cheap. While insurance companies usually cover them for diabetics, they will typically not be covered for non-diabetic monitoring. Some systems sold can range from a couple hundred to more each month.

The bottom line is that the data is not strong or robust enough to support the use of this wearable technology in improving health. It’s definitely trendy, is cutting edge, and it has a shiny value proposition and only you can decide if it's worth the cost and use of invasive technology for unproven and questionable results.

References

Blood Glucose Monitoring Devices Market Size, Trends, Growth, Report 2022-2030. (2022, July 22). BioSpace. Retrieved from https://www.biospace.com/article/blood-glucose-monitoring-devices-market-size-trends-growth-report-2022-2030/

Cleveland Clinic. (2021). Continuous Glucose Monitoring. Retrieved from https://my.clevelandclinic.org/health/drugs/11444-glucose-continuous-glucose-monitoring

Ometov, A., Shubina, V., Klus, L., Skibinska, J., Saafi, S., Pascacio, P., … & Lohan, E. L. (2021). A Survey on Wearable Technology: History, State-of-the-Art and Current Challenges. Computer Networks, 193, 108074. doi: https://doi.org/10.1016/j.comnet.2021.108074

Schmerling, R. (2021, June 11). Is blood sugar monitoring without diabetes worthwhile? Harvard Health Publishing, Harvard Medical School. Retrieved from https://www.health.harvard.edu/blog/is-blood-sugar-monitoring-without-diabetes-worthwhile-202106112473