When it comes to glucose management, many common terms may be used ambiguously, and patients may be unfamiliar with the true meaning of these terms. Recognizing common terms used in the context of glucose management is particularly important for individuals with related health conditions looking to better understand their health and how to improve it.
Glucose and “Blood Sugar”
Glucose is a monosaccharide, the smallest of the building blocks that make up carbohydrates (one of the three macronutrients, alongside protein and lipids/fat). Monosaccharides (i.e. glucose, fructose, and galactose) and disaccharides (i.e. maltose, sucrose, and lactose) are called “simple sugars” while polysaccharides (i.e. amylose, cellulose) are called “complex carbohydrates.”
What most people know as “table sugar,” the white, granular sugar used in baking and as a sweetener, is actually a disaccharide called sucrose. Sucrose is a combination of two monosaccharides, glucose and fructose. So, while “glucose” and “sugar” are not precisely the same thing, the terms are used interchangeably likely because glucose is both a component of table sugar and the most abundant carbohydrate building block.
When either of these terms is used in the context of blood sugar or blood glucose, the reference is to the amount of glucose currently circulating in the body via the bloodstream. Glucose is found directly in many foods (i.e., fruits, vegetables, and grains) and as a component of other carbohydrates, such as in combination with galactose to make lactose, the disaccharide found in dairy products. The monitoring of blood glucose is an important component of many health conditions related to glucose management, such as hyperglycemia in type 2 diabetes.
Hypoglycemia vs. Hyperglycemia
Hypoglycemia is characterized by a state of low blood glucose (70 mg/dL or lower), while hyperglycemia is characterized by the opposite (240 mg/dL or higher). Acute to chronic hypoglycemia or hyperglycemia may be a result of a number of things and vary based on age, health status, and other factors.
|Potential causes of hypoglycemia include:
Common symptoms of hypoglycemia include:
Hypoglycemia may be addressed acutely with:
|Potential causes of hyperglycemia include:
Common symptoms of hyperglycemia include:
Hyperglycemia may be addressed acutely with:
Type 1 vs. Type 2 Diabetes
Type 1 diabetes, also referred to as “Juvenile Onset” or “Insulin-Dependent” diabetes, is caused by an autoimmune reaction in the body, whereas type 2 diabetes is caused by insulin resistance as a result of a culmination of a variety of metabolic risk factors. Type 2 diabetes, also known as “Adult Onset” or “Noninsulin Dependent” diabetes, is the type of diabetes most commonly referred to in the context of glucose management. Type 2 diabetes is much more common than type 1 diabetes, and thus is often simply referred to as “diabetes.”
Insulin & Insulin Resistance
Insulin is a hormone key for regulating blood glucose levels: it is produced by the pancreas in response to an individual beginning to consume a meal. Insulin production increases as the body digests and absorbs carbohydrates (including glucose). Insulin promotes the use of glucose for energy, storage of excess glucose as glycogen, and glucose uptake by muscle and fat cells. Type 2 diabetes results when body cells stop responding normally to insulin, leading to increased insulin production by the pancreas (i.e. insulin resistance). Ultimately, in type 2 diabetes, insulin production by the pancreas cannot keep up with the demand, and blood glucose levels rise.
Risk Factors for Type 2 Diabetes
Preventative measures for reducing the risk of type 2 diabetes include addressing risk factors that can be changed with lifestyle adjustments: weight loss, physical activity, and stress management. Risk factors for type 2 diabetes include:
- Being overweight
- Being 45 or more years old
- Close family member with type 2 diabetes
- Low physical activity
- Gestational diabetes or giving birth to a baby weighing more than nine pounds
- Polycystic ovary syndrome (PCOS)
Clinicians may diagnose an individual as having prediabetes if their blood glucose levels are higher than normal but not as high as needed for an official type 2 diabetes diagnosis. More than one-third of American adults (88 million) have blood glucose levels associated with prediabetes, and a large majority (84 percent) are unaware of their metabolic status. Similar to type 2 diabetes, prediabetes increases an individual’s risk of cardiovascular disease and stroke.
Blood Glucose Monitoring
Monitoring blood glucose levels optimally includes checking right after waking up (before breakfast), before any meal, two hours after a meal (“postprandial glucose”), and right before bedtime. Target blood glucose levels include 80-130 mg/dL before a meal and 180 mg/dL or less two hours after a meal begins.
A continuous glucose monitor (CGM) is used to measure the amount of glucose in a small sample of blood using a sensor inserted under the skin. Measurements are taken every couple of minutes with a small device that attaches securely to the top layer of the skin with an adhesive patch.
Another blood test that measures blood glucose is a hemoglobin A1c (HbA1c) test, which measures glucose levels over the prior three months. HbA1c is a measure of the percentage of red blood cells with hemoglobin with glucose attached. Hemoglobin is the protein found in red blood cells responsible for transporting oxygen from the lungs, through the circulation, and delivered to cells all over the body. Hemoglobin A1c simply refers to the hemoglobin proteins that are coated with glucose.
HbA1c tests can be used to assess and manage metabolic status. The higher the HbA1c level, the higher the risk for diabetes complications:
- Prediabetes (HbA1c 5.7 – 6.4%)
- Diabetes (HbA1c 6.5% and above; 154 – 240 mg/dL)
Factors that may influence A1c results include:
- Kidney failure, liver disease, severe anemia
- Opioids, HVI medications, and other medicines
- Blood loss or transfusions
Glycemic Index vs. Glycemic Load
Two similar but different terms describe the glycemic response, the way the body reacts to different types of carbohydrates in terms of corresponding blood glucose levels. The glycemic response is significant because drastic changes in insulin and blood glucose levels are associated with adverse health effects, especially for people with diabetes.
Glycemic index is a ratio of the blood glucose response triggered by a certain food compared with a standard (i.e., the response to glucose alone). For example, potatoes and short-grain white rice have a higher glycemic index, while fat-free yogurt and broccoli have a lower glycemic index. Factors affecting variations in glycemic index include:
- Starch structure
- Fiber content
- Food processing
- Physical structure
- Amount of protein and fat accompanying carbohydrate consumption during a meal
Glycemic load may be a more accurate and effective term to understand glycemic response, as it factors in both a food’s glycemic index and the typical amount of carbohydrate consumed from that food. Glycemic load is calculated by multiplying the number of grams of carbohydrate in one serving of the food by the glycemic index and dividing by 100.
It is important when using glycemic index while choosing foods to consider that the glycemic index is based on a serving of food that provides 50 grams of carbohydrate, although in reality, a serving is likely higher than that (50 grams of mashed potatoes equals 1/5 cups). For both glycemic index and glycemic load, only the glycemic response prompted by one single food is represented, and meals often contain multiple ingredients from various food groups.
Supporting a healthy lifestyle includes maintaining a diverse diet abundant with fruits, vegetables, whole grains, and lean proteins. These foods are made up of varying amounts of protein, fat, and carbohydrates, all of which are digested in different ways. As a building block of carbohydrates, glucose is a significant component of understanding health conditions related to insulin sensitivity. Identifying and defining key terms surrounding glucose management is an important step toward promoting a health and wellbeing.