Understanding Blood Glucose and Insulin Resistance
By Leigh Pujado - Hibiscus Nutrition
What is glucose?
Glucose is the body’s favorite source of energy. We often get it by eating starches, such as breads, rice, potatoes, oats, pasta, or grains, and from sugars in fruit or sweets and desserts. When we eat these starches and sugars, they break down into glucose molecules, raising glucose levels in the bloodstream. After a meal, it is normal to have a rise in blood glucose and under optimal conditions, the glucose enters the cells of our body to be burned up and turned into energy. However, excess glucose floods our cells when we overeat starchy or sugary foods, leaving them overwhelmed and dysfunctional. Chronically high blood glucose levels give us cravings, make us tired and irritable, and create inflammation in the body. Long-term elevations lead to insulin resistance, PCOS, diabetes, and cardiovascular disease (Campos, 2012).
What is insulin?
Insulin is a storage hormone released by the pancreas into the bloodstream when blood glucose is high. It facilitates moving glucose from the blood into storage in the muscles, liver, and fat tissue cells. The more starchy, sugary foods you eat, the more the pancreas is called upon to pump out more insulin to clear out all the excess blood glucose.
What is insulin resistance?
Insulin resistance is the cell’s attempt at self-preservation in the presence of chronically high blood glucose and insulin levels. The cells become overwhelmed when blood glucose levels are too high too frequently. Even though lots of insulin may be present to clear the glucose, the cells can only allow so much glucose inside so they stop responding to insulin’s signal. The more the cells resist insulin’s signal, the higher blood glucose climbs. Once cells become insulin resistant, even small amounts of starches and sugars cause spikes in blood glucose and insulin levels. Because cells are resisting insulin’s signal, the pancreas releases more and more insulin in an attempt to clear the glucose; thus, insulin also remains high.
What is the problem with having high insulin levels?
Remember that insulin is a storage hormone, so when insulin is high, your body thinks, “Winter is coming,” and “It’s time to store more energy.” High insulin prevents weight loss and creates weight gain. Your hunger and satiety hormones go haywire, and your body thinks you need to eat more. In the long term, high insulin contributes to metabolic syndrome, heart disease, cancer, cognitive decline, infertility, and fatty liver disease (Kolb, et al, 2020). Insulin resistance is also a driver of Alzheimer’s disease (Sędzikowska & Szablewski, 2021).
What can I do to lower my blood glucose?
Get your glucose down by reducing the amount of starches and sugars in your diet. This means eating less bread, pasta, potatoes, oats, corn, rice, and anything containing sugar. This also means that the mainstay of your meals must be something other than sandwiches, wraps, and pasta. If you are already eating a diet made up primarily of whole foods, this will be easier than if you are eating a predominantly processed diet. If you prepare most of your meals, this will be easier than if you rely on restaurants for most of your food.
Stop eating carbs for breakfast! Cereal for breakfast and the slogan “Breakfast is the most important meal of the day” was invented by the Kellogg company to sell more processed, grain-based cereals. Contrary to what Mr Kellogg told us, you can skip breakfast altogether. Or, eat a savory breakfast, not a sweet breakfast: Eggs, sausage, bacon, leftover meat, unsweetened yogurt, nuts, cottage cheese.
Stop putting sugar in your morning coffee! Coffee with skim milk and sugar on an empty stomach will illicit a major spike in blood sugar. If you must have it sweet, consider using something better for your glucose levels, like Stevia or Allulose. Try having your coffee with a splash of cream, half and half, or nut milk.
Eat more protein! You can find quality protein in eggs, meat, dairy products, nuts, beans, and legumes. Reach for protein first, as it does not readily raise glucose levels.
Eat more quality fats! Fat does not raise glucose levels and, in fact, helps stabilize blood sugar. Healthy fats include extra virgin olive oil, wild-caught fatty fish like salmon or sardines, avocados, nuts, and pasture-raised animal products, including meat, dairy, and eggs.
Add more fiber to your diet. Your body can’t digest fiber, so it slows down digestion of everything else. This can dramatically reduce blood glucose spikes (Xie, et al, 2021). Fiber leaves you feeling fuller longer; the more vegetables you eat, the more fiber you’ll get. Beans are also a great source. Yes, whole, unrefined grains have fiber, but they should still be kept to a minimum because their high carbohydrate content can spike glucose.
When you eat something starchy, eat it with fat, protein, and fiber so that you digest more slowly, thus limiting your glucose spike. For example, a slice of toast with nut butter, avocado, or cheese is better than toast with jam.
Exercise! Moving your body pushes glucose into the cells. Even a 10-minute walk after a meal does wonders for lowering blood glucose levels. Building muscle will also do wonders to lower your glucose because muscle acts as a glucose sink. The more muscle tissue you carry, the better your body can clear glucose from the bloodstream.
What kinds of tests help me manage my blood glucose?
Fasting Glucose - This is usually drawn on most standard labs and reflects how diabetic you are: Below 100 is not diabetic, 100-125 is prediabetic, and above 125 is diabetic. It is impacted by what you’ve eaten in recent weeks, recent exercise, or even sleep quality.
hbA1C - This reflects your average blood glucose over 3 months. It is based on the life of a red blood cell whose hemoglobin binds to glucose in the blood. Your A1C level better reflects your insulin sensitivity because it measures three whole months of blood glucose. If you ordinarily eat lots of sugar but avoid sugar for the weeks leading up to your blood draw, your fasting glucose might be better, but your A1C would tell the truth.
Fasting insulin - Fasting insulin is even better than A1C at determining how insulin-sensitive you are. It tells you how hard your pancreas is working to clear blood glucose and is the lab marker that will change first, even before fasting glucose (Johnson et al., 2010). This test is seldom drawn but is so valuable, especially for catching early insulin resistance, that you should ask your doctor to order it every time you get bloodwork. There is some discrepancy over ideal levels, but your levels are relative to you. If your fasting insulin is creeping up, you are becoming more insulin resistant. If your levels are declining, you are becoming more insulin sensitive. Normal fasting insulin can range from 2.6-24.9 mcIU/ml but if your goal is insulin sensitivity, ideally it should be less than 10 μU/mL (Bikman, 2020).
Continuous Glucose Monitor (CGM) - This device is a wearable monitor with a sensor that can be linked to your smart phone or watch, tracking your blood glucose in real time. CGM’s are great for learning which foods cause your blood sugar to spike and which foods keep it stable. Patients diagnosed with diabetes or pre-diabetes may be able to get the cost of CGMs covered by insurance. Non-diabetics may find them useful to optimize their insulin sensitivity and health.
References:
Bikman, B. Why We Get Sick. Bellbella Books. 2020
Campos C. (2012). Chronic hyperglycemia and glucose toxicity: pathology and clinical sequelae. Postgraduate medicine, 124(6), 90–97. https://doi.org/10.3810/pgm.2012.11.2615
Johnson, J. L., Duick, D. S., Chui, M. A., & Aldasouqi, S. A. (2010). Identifying prediabetes using fasting insulin levels. Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists, 16(1), 47–52. https://doi.org/10.4158/EP09031.OR
Kolb, H., Kempf, K., Röhling, M., & Martin, S. (2020). Insulin: too much of a good thing is bad. BMC medicine, 18(1), 224. https://doi.org/10.1186/s12916-020-01688-6
Sędzikowska, A., & Szablewski, L. (2021). Insulin and Insulin Resistance in Alzheimer's Disease. International journal of molecular sciences, 22(18), 9987. https://doi.org/10.3390/ijms22189987
Xie, Y., Gou, L., Peng, M., Zheng, J., & Chen, L. (2021). Effects of soluble fiber supplementation on glycemic control in adults with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials. Clinical nutrition (Edinburgh, Scotland), 40(4), 1800–1810. https://doi.org/10.1016/j.clnu.2020.10.032