Glucose is a type of sugar that is the main source of energy for living organisms. Your body can make glucose from other substances but a large portion of our glucose comes from carbohydrates in food and fluids that we eat and drink. Blood glucose levels are measured in milligrams per deciliters(mg/dl). Most often in order to diagnose diabetes blood glucose levels are most frequently measured in the fasting state, (eight hours after your last meal) and two hours after eating. CGMs (continuous glucose monitors) measure glucose in the interstitial fluid which is the fluid that surrounds cells and is found in spaces between blood vessels and cells. The CGM’s advantage is that it can measure glucose readings every 1 to 15 minutes depending upon the device used. Present FDA approved CGMs used for diabetes are required to have a MARD (mean absolute relative deviation) of 10% or less. This typically means that a CGMs accuracy has to be within 10% or less of an actual blood glucose level. Generally interstitial glucose levels may lag behind plasma glucose levels by 5 to 15 minutes, however most CGM’s have built-in algorithms that factor in this change.
Normal fasting blood sugars (FBS) in non-diabetic individuals are supposed to be less than 100 mg/dL, but it turns out that individuals who have that have fasting blood sugars greater than 85 to 87 have a greater chance of becoming a diabetic. For every 1 mg/dL increase over 87 there is a 6% potential increase in the chances of becoming a diabetic. If you’re 2hour blood sugar after eating goes above 200, you are typically considered a diabetic and your overall mortality rate is increased by 100% and your coronary artery disease mortality rate is increased by 50% even if you’re fasting sugar is less than 100.
There is often glucose variability after eating certain foods that make our blood sugars spike. The maximum spike or excursion two hours after eating should be less than 36 mg/dL for the normal individual and 72 to 90 mg/dL for the well-controlled Type II Diabetic. Time in range, is another important indicator of good metabolic health. Generally, a normal healthy individual should have blood sugars between 70 and less than one 140, 95 to 100% of the time. While using CGM these levels might be a little higher due to the variation as noted previously between blood glucose levels and interstitial glucose levels. In diabetics there will be significantly higher variability, while in normal individuals there is generally little variability. If you are prediabetic, then you will also have an increase in variability. One of the earliest predictors of insulin and glucose dysregulation is actually glucose variability. In Type II Diabetes increased variability is associated with an increase in microvascular complications (nerve, eye, and kidney problems) and macrovascular complications (coronary artery disease and stroke). Increased variability is associated with increased inflammation in the body along with the production of substances that can damage our cells (oxidative stress).
A study over three decades looking at nondiabetic adults 25 to 30 years of age, revealed that high glucose variability eventually led to worse mental processing, language fluency and memory independent of fasting blood sugar levels (Cardia Study, Diabetes Care, Dec.2018).
How certain food affects your blood sugar will vary from person to person. While we can designate a glycemic index value to a specific food, (rank of foods 1 to 100 based on how they affect your blood sugar), that value may not predict accurately how your sugar will react to that given food. This is where using a CGM can be quite helpful and establishing foods to avoid to prevent glucose spikes and variability.
It also turns out that significant variability of your glucose levels can also affect your sleep. The more variability, the more likely you will have less restful sleep and if you are a poor sleeper it is likely to cause glucose spikes. It is generally recommended that all of us get somewhere between six and eight hours of restful sleep per night.
Additional reasons for potential glucose spikes and variability other than individual glucose metabolism and sleep include increased age, increasing BMI (body mass index), stress, physical activity, and medication’s such as statins, beta blockers, and caffeine.
Studies are ongoing to help look at the benefits of CGM’s to potentially decrease coronary artery disease, fatty liver disease, dementia, menopausal weight gain, acne and migraines. Using a CGM along with the use of our Clova Health app and our Clova coaching can potentially motivate you to improve your overall health by helping you lose weight, decrease glucose variability, decrease glucose excursions, improve sleep, decrease fat mass and improve cognition.