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Interpreting Your Own CGM Data: A Guide for Non-Diabetics and Health Enthusiasts

Posted on Wednesday June 26, 2024 in Metabolic Health

An article by Dr Edward Leatham, Consultant Cardiologist. The opinions expressed in this article are entirely mine and not those of SCVC or a consensus view.

Continuous Glucose Monitors (CGMs) have revolutionised the way diabetic patients manage their blood sugars, alerting them to potential hyperglycaemia or hypoglycaemia—conditions that could lead to hospital admissions or even comas if left unmanaged. Developed over ten years ago, these devices were initially designed for diabetics to ensure their food intake matched their insulin requirements effectively. However, since 2018, the usage of CGMs has expanded beyond the diabetic community, becoming a popular tool among the health-conscious looking to assess their lifestyle through real-time glucose data.

The burgeoning interest in CGM technology is not just a fad. It is backed by a growing number of health apps that utilise glucose data to offer users personalised health insights. Despite the lack of formal clinical trials recommending routine CGM use for non-diabetics, the medical community cannot ignore its potential benefits for metabolic health. Reports suggest that glucose dysregulation—characterised by significant variations and spikes in glucose levels, especially after consuming high glycaemic index foods—can be detrimental to one’s health.

At SCVC we host one of the UK’s largest independent services for advanced cardiac CT imaging. These techniques involve AI data processing by Heartflow and  (Caristo based in Oxford) which measure coronary inflammation. We have found unexplained high levels of coronary artery inflammation in patients without traditional risk factors like elevated LDL or lipoprotein(a). This spurred interest in other potential contributors to heart disease, including glucose dysregulation. Recognising this, some medical practices, like ours, now offer formal metabolic health assessments, incorporating glucose monitoring with insulin measurements and glucose tolerance testing over a 7-10 day period to obtain a comprehensive view of a patient’s metabolic health. If we discover glucose dysregulation that could be contributing to coronary inflammation, it seems sensible to recommend lifestyle changes. We have already seen that changing what, and how you eat, can improve the current glucose profile (CGP), without additional medication.

For individuals uncertain about the need for such detailed assessments, SCVC offers an interpretation service. Patients send in their own CGM data for us to analyse, where we use sophisticated processing systems to provide a detailed medical report.

Purchasing a CGM is now more accessible than ever, with devices available over the counter or directly from medical suppliers. This allows individuals to independently monitor their glucose responses to various foods and then make lifestyle choices, based on our medical research and professional advice that we provide.

What to Look for in Your CGM Data

It’s essential to understand that CGMs, while helpful, do not offer the same accuracy as direct blood sugar measurements and should not be solely relied upon for diabetes diagnosis. The true value of CGMs lies in their ability to track glucose fluctuations over time, particularly after meals. Here’s what to look out for:

  • Post-Meal Spikes: A healthy glycaemic profile typically ranges from 3.8 to 7.8 mmol/L. Glucose excursions above this range following meals, especially if rapid (ie ‘spikes’) occur or if recurring daily, may represent poor metabolic health and thus probably indicate the need for dietary adjustments. Monitoring how glucose levels respond within 30 minutes of eating can help identify foods that cause unhealthy spikes.
  • Dietary Adjustments: If consistent daily glucose spikes are observed, consider reducing intake of high glycaemic foods such as fruit juices and smoothies, and refined carbohydrates like potatoes and bread.
    Increasing fibre intake can also help manage and stabilise glucose levels.
  • Daily Variations: Lesser fluctuations are normal and depend on meal composition, timing, and personal metabolic responses. It may be quite alright to see occasional spikes between 7.8 to 10 mmol/L during an average week, but more  frequent or higher spikes warrant attention and consideration of dietary changes.

We have set out a series of glucotype profiles that we use alongside our metabolic health assessment. For patients found to have anything other than type II or II, we generally encourage dietary changes.

Considerations for Overweight Individuals

For those classified as overweight or obese, CGM data can be particularly insightful: if high blood glucose responses to meals and snacks are found, an alteration in food intake can really help with weight management. However plenty of high BMI individuals  exhibit flat glucose curves, which suggests rapid glucose clearance from the bloodstream into adipose tissue may be a factor that can facilitate weight gain. Understanding how one’s body processes glucose can lead to more tailored and effective weight management strategies.

What about feeling well?

We can’t make any promises, as there is no peer reviewed research yet published, however we can report that many people showing glucose spikes, once dietary adjustments are made, report better sleep, less daytime sleepiness and general increase in wellbeing.

In conclusion, whether you are diabetic or simply health-conscious, understanding how to interpret CGM data can significantly enhance your approach to diet and lifestyle management. By recognising your body’s unique responses to different foods and activities, you can make informed decisions that promote better metabolic health and overall well-being.

If you have worn a Freestyle Libre CGM, can access your dataset and would like your glucose data to be data processed and/or reported by our medical experts, get in touch and we can provide a quotation free of any obligation to proceeed.

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