Glucose and carbohydrate metabolites play an important role in providing energy to body tissues and in cellular respiration. A prolonged increase or decrease in its content leads to severe consequences that threaten human health and life. Therefore, doctors attach great importance to the control of normal blood glucose levels. In this article, we will give a complete guide about average blood glucose levels. For diagnostic purposes, it is essential to know the reference values. As well as deviations within and outside the norm. Which depends on the time of meals and the presence of diabetic symptoms. But first things first.
Normal blood glucose levels
Like any other carbohydrate, sugar cannot be directly assimilated by the body and requires splitting into glucose with special enzymes’ help. That end in “-ase” and are collectively called glycosyl hydrolases (glycosidases), or sucrases. “Hydro-” in the name of a group of enzymes indicates that sucrose’s breakdown into glucose occurs only in an aqueous medium.
Good to know!
Sugar, or sucrose (beet, cane sugar), being a multisaccharide, consists of two monosaccharides – fructose (50%) and glucose (50%). Other sugars are also subject to decomposition to glucose – maltose (malt sugar), lactose (milk), nigerose (black rice), trehalose (mushroom), turanose (honey), cellobiose (woody birch), etc. Gradually decreasing in molecular weight in the process of enzymatic hydrolysis, but this process is slower. Hence the name – “slow” carbohydrates.
If the sugar content is outside the normal range, then:
- energy starvation of cells occurs, as a result of which their functionality is significantly reduced; if a person has chronic hypoglycemia (low glucose), then damage to the brain and nerve cells may occur;
- Excess substances are deposited in the proteins of tissues, causing their damage (with hyperglycemia. They undergo destruction of the tissues of the kidneys, eyes, heart, blood vessels, and the nervous system).
- The unit of change for glucose is millimoles per liter (mmol / L). Its level depends on the person’s diet, motor and intellectual activity, and the pancreas’ ability to produce insulin, which has a sugar-reducing effect and the intensity of the production of hormones that neutralize insulin.
Normal blood glucose levels (sugar): the norm of indicators
The study of sugar levels is carried out in several ways, for which there are corresponding indications. Determining the concentration of this substance allows you to diagnose several serious diseases.
Normal blood glucose levels: Fasting blood sugar.
The general norm of glycemia in adults is 4.1-5.9 mmol / l, in children from one month to 14 years old – 3.3-5.6 mmol / l, in infants under one-month-old – 2.8-4.4 mmol / l in the elderly (over 60 years old) and women during pregnancy. The indicators may slightly increase and reach 4.6–6.7 mmol / l.
A similar study is being conducted:
- During preventive examinations.
- With obesity or the presence of pathologies of the liver, adrenal glands, thyroid gland, pituitary gland.
- in the presence of hyperglycemia symptoms: increased urination, constant thirst, blurred vision, fatigue, and susceptibility to infections.
- In the presence of signs of hypoglycemia: increased appetite, sweating, clouding of consciousness, weakness.
- To monitor the patient’s condition: in case of pre-diabetic disease and diabetes.
- To exclude gestational diabetes: women at 24-28 weeks of pregnancy.
- The detection of fasting glucose in a 7.0 mmol / l and above volume is a severe reason for additional laboratory tests, including for hormones and enzymes.
Blood sugar “loaded” with glucose.
If the results of a formal analysis for sugar raise doubts among experts, then a glucose tolerance test is performed. Combined with normal blood glucose levels, with periodic detection of sugar in the urine. An increase in the daily amount of urine, a hereditary tendency to diabetes, or the presence of retinopathy of unexplained origin. As well as their children.
During the examination, blood is taken from the patient on an empty stomach. And then, he takes 75 grams of glucose dissolved in tea. If the plasma glucose level 2 hours after administration in the oral glucose tolerance test is 11.1 mmol / L or higher, this is a direct indication of diabetes mellitus. If the glucose concentration is below 11.1 mmol / L but above 7.8 mmol / L, we are dealing with impaired glucose tolerance.
Normal blood glucose levels: Glycated hemoglobin
Connection of erythrocyte hemoglobin with glucose. Measuring glycated hemoglobin concentration allows you to determine the blood sugar content for the last 2-3 months.
The study is shown:
- For the diagnosis of pre-diabetes and diabetes.
- To study the dynamics of the state of diabetic patients.
- To assess the effectiveness of the prescribed treatment.
A value of 6.5% or more is a criterion for diagnosing diabetes mellitus.
It is a combination of glucose with plasma proteins, which allows you to determine the average sugar content over the last 2-3 weeks. The average concentration of fructosamine is less than 319 μmol / L.
- when there is a sharp change in the diabetes treatment plan;
- during pregnancy in women with diabetes;
- in patients with anemia (in their case, the study for glycated hemoglobin does not give accurate results).
Suppose fructosamine is below 286 μmol / L. This is a reason to suspect hypoproteinemia (hypoalbuminemia) in nephrotic syndrome, diabetic nephropathy, hyperthyroidism, or heavy intake of ascorbic acid.
It is an integral part of the pancreas’ secretion, which allows you to assess the production of insulin. Measuring the amount of this substance makes it possible to diagnose diabetes and evaluate its treatment effectiveness. C-peptide and insulin are produced in an equal ratio, but the concentration of C-peptide is constant and does not depend on the glucose level in a person’s blood. Accordingly, the determination of its amount allows you to assess the production of insulin accurately. Average values of C-peptide on an empty stomach vary widely – 260-1730 pmol / l.
If this factor is excluded, beta-cell hypertrophy, insulinoma, the presence of antibodies to insulin, non-insulin-dependent diabetes mellitus, somatotropinoma (pituitary tumor), apudoma (a tumor that uncontrollably produces insulin into the blood), renal failure are possible. A low level of C-peptide indicates insulin-dependent diabetes mellitus, insulin therapy, alcoholic hypoglycemia, stress. The presence of antibodies to insulin receptors (in insulin-resistant type II diabetes mellitus).
Red blood cells: the most numerous cells in the blood
If you look at them under the microscope, they appear as small flying saucers, with a biconcave shape and a dark pink color slightly lighter in the center. They are the red blood cells, the most numerous cells in our blood. And also those that give our vital fluid its characteristic ruby red color. We discover all the characteristics of these extraordinary cells that we produce in a continuous cycle throughout our life.
- From 4 to 6 million per cubic ml are the red blood cells present in an adult’s blood (the amount varies according to gender and age, women have a little less than men).
- Erythrocytes are their second name because the term erythrose in ancient Greek meant red.
- 7-8 microns (thousandths of a millimeter) is the average red blood cell diameter.
- 25% of the total number of cells in the body is the percentage of red blood cells we possess.
- One hundred twenty days is the average duration of their life.
- They have no nucleus and other internal structures (e.g., mitochondria and ribosomes present in most body cells). Therefore, they cannot replicate, produce proteins, or perform aerobic respiration to generate energy like other cells.
- Erythropoiesis is the term that indicates the process of generation of red blood cells by the bone marrow starting from proerythroblasts, upon stimulation of a hormone produced by the kidneys, erythropoietin.
Functions of the Normal blood glucose levels
Image depicting lungs and blood cells in the primary background function of red blood cells promotes gas exchange in the body’s organs and tissues. What does it mean? Far from being a simple task, as it might seem! On the contrary, our body depends on this exchange, without which we could not survive. Our organism’s respiratory and cardiovascular systems converge towards this function: supplying oxygen (nourishment) to the individual components of each organ and tissue, or cells, so that they can perform the biological processes to which the organs they belong to are responsible. All thanks to our blood and our little red “workers”. Going into the merits, let’s see what this complex mechanism of transport and exchange entails. First, let’s consider that oxygen is vital in our body and that we get it with the act of breathing.
Red blood cells and blood group
We have seen that one of the “attributes” of red blood cells is the fact of having (or not) antigens on the membrane that covers them. This feature allows us to identify ourselves in a blood group, which in turn is crucial information in case we need to receive a transfusion. Let’s try to understand what we are talking about, starting from the general classification.
There are four main blood groups with a variant by type linked to the RH factor, which we will explain shortly, namely:
- A+, A-
- B+, B-
- AB +, AB-
- For a total of eight possibilities.
- But let’s see the characteristics of each blood group.
- Group A . Antigen A is present on the surface of red blood cells and antibody B in plasma.
- Group B. On the red blood cells, we find antigen B and in the plasma antibody A.
- Group 0. There are no antigens present on these red blood cells’ lining membrane, but in the plasma, we find both antibodies A and B.
But what are these antigens, and why do we need to know if we have them or not, and what kind?
How is the blood group determined?
It is quickly discovered with a blood test but can also be “predicted” based on one’s parents’ group. It is, in fact, a hereditary characteristic, which follows the Mendel laws of recessivity and dominance. As we have seen, the two main antigens are A and B (in reality, many others are not useful in determining the blood group). They are dominant, which is why group 0 (which has no antigens) is recessive. In Italy, blood groups’ distribution varies slightly depending on the geographical area(North, South, Center, and islands). In general, this is the spread.
High and low red blood cells
The red blood cell count is part of routine blood tests and is included in the blood count associated with other difficulties related to our blood cells. On average, we have seen that an adult individual has a quantity of circulating erythrocytes equal to 5 million per milliliter of blood. That is, about 25 billion red blood cells!
But, if we go specifically, we find that:
- In adult men, erythrocytes (RBC) count in blood tests is between 4.4 and 6 million per ml.
- In adult women-pregnant, on the other hand, the number of units drops a little, settling between 3.9 and 5.3 million per ml.
Taking the blood test now and then is essential because it gives us a snapshot of our general health and offers us useful information about our physiology. One of the indispensable indicators is precisely the composition of the blood itself: its constituent cells’ number and quality. Therefore, having red blood cells higher or lower than average can have meanings, even if not necessarily pathological or otherwise worrying.
Diseases of the red blood cells
Various pathologies cause a decrease or an increase in the production of red blood cells. And that produces more or less severe symptoms. We have specified that the most common diseases or anomalies. That leads to an impoverishment of our blood, and the cause of a reduced or significantly reduced generation of erythrocytes (or hemoglobin) is anemia. Leaving aside the most widespread and benign, the one resulting from an iron deficiency. Which we will discuss in the next paragraph, the others are due to different causes. For example, red blood cells that are too low can result from a bone marrow disorder, which produces erythrocytes that are abnormal in size and morphology.
If there are not enough red blood cells, to whom do the oxygen atoms bind. And how do they reach the cells of all parts of the body? Common symptoms of anemia are a sense of fatigue, memory and concentration deficits, lightheadedness and dizziness, tachycardia, and shortness of breath: the organism goes into suffering.