Why popular blood sugar monitors could actually be harming your health

Popular glucose monitors used to take regular blood sugar readings could be driving poor diets and food restrictions due to inaccurate measurements, according to a new study.

Continuous Glucose Monitors (CGMs) take blood sugar readings every five minutes and were originally designed for people with diabetes to assess how their body responds to different foods.

But they are growing in popularity and in recent years have increasingly been used by the health-conscious to track their diet and avoid glucose spikes.

Carried out in healthy, non-diabetic volunteers, the research compared results from a CGM to the gold standard finger-prick test for blood sugar levels.

Scientists found that the CGMs consistently reported higher levels than the finger-prick test. The monitors overestimated the time spent above the Diabetes UK’s recommended blood sugar level threshold by nearly 400 per cent, causing unnecessary concern for people whose blood sugar was actually well-controlled.

Professor Javier Gonzalez, from the university’s department of health, warned people should stick with the finger-prick test if they are looking for accurate readings.

“Continuous glucose monitors (CGMs) are fantastic tools for people with diabetes because even if a measurement isn’t perfectly accurate, it’s still better than not having a measurement at all,” he said.

“However, for someone with good glucose control, they can be misleading based on their current performance."

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Source: The Independent, 26 February 2025