Continuous Glucose Monitors (CGMs) have seen a surge in popularity in recent years, but a new study from the University of Bath suggests that these devices may not be as accurate as previously believed. Originally designed to assist individuals living with diabetes in managing their blood sugar levels, CGMs are now being used by health-conscious individuals to monitor how different foods impact their glucose levels.
The research, published in The American Journal of Clinical Nutrition by the University’s Center for Nutrition, Exercise, and Metabolism, cautions that CGMs could be overestimating blood sugar levels in healthy adults, potentially leading to unnecessary dietary changes. The study involved measuring blood sugar responses in healthy volunteers (non-diabetic individuals within a healthy BMI range) using two methods: a CGM (specifically, the Abbot Freestyle Libre 2) and the traditional finger-prick test.
The aim of the research was to evaluate the accuracy of CGMs in measuring responses to various fruit-based products, including whole fruits and smoothies. The results revealed that the CGM consistently reported higher blood sugar levels compared to the finger-prick tests, indicating potential inaccuracies in the readings provided by CGMs.
Key findings from the study highlighted significant discrepancies in the CGM measurements. For instance, when participants consumed a smoothie, the CGM overestimated the glycemic index (GI) by 30%, reporting a higher GI compared to the traditional test results. Similarly, whole fruits were misclassified as medium or high-GI foods by CGMs, leading to potential misconceptions about the impact of fruits on blood sugar levels.
Furthermore, the study debunked the myth that blending fruits into smoothies raises their GI, emphasizing that fruits like apples, bananas, mangoes, and oranges remain low on the glycemic index whether consumed whole or blended. The research concluded that CGMs may not be a reliable method for determining the GI of foods accurately.
Professor Javier Gonzalez from the University of Bath highlighted the limitations of CGMs for healthy individuals, stating that reliance on these devices could result in unnecessary dietary restrictions or poor food choices. He emphasized the importance of using traditional methods for accurate blood sugar assessment and called for further research to improve the performance of CGMs in the future.
Helen Whitby, Company Nutritionist at Innocent Drinks, supported the findings of the study, affirming that smoothies and whole fruits offer steady energy without causing sharp blood sugar spikes. She emphasized the nutritional benefits of fruits and encouraged individuals to incorporate them into their diet for overall well-being.
In conclusion, the research raises important considerations about the accuracy of CGMs in measuring blood sugar levels, particularly in healthy individuals. While CGMs remain valuable tools for individuals with diabetes, the study suggests that caution should be exercised when interpreting the readings provided by these devices for non-diabetic individuals. Further research and improvements in CGM technology are needed to enhance their accuracy and reliability in monitoring blood sugar levels effectively.
