Let's talk about Diabetes Mellitus

Let's talk about Diabetes Mellitus

Diabetes Mellitus is a chronic disease characterized by the body’s inability to produce or respond properly to insulin, which results in an abnormally high level of glucose in the blood.

Scientifically, the full name of the disease diabetes mellitus is used, instead of just diabetes, as a way of distinguishing it from “diabetes insipidus”, another rarer disease, similar to diabetes mellitus. In this article, whenever diabetes is mentioned, we are referring to diabetes mellitus.


Glucose (the sugar present in the blood) is the main source of energy used by our body and is vital for the normal functioning of our organs and tissues. But in order for this sugar to be processed by the body, it has to be transported from the blood to the inside of our cells and this is where insulin comes in.


Insulin is a hormone produced in the pancreas (even before we are born) and is primarily responsible for “removing” the sugar present in the blood (glucose) and transporting it to the interior of the cells, thus lowering the concentration of glucose in the blood. It is the main regulator of our glycemia  level. Glycemia is the term we use when referring to the amount of sugar in the blood.


When someone suffers from diabetes, we witness a set of metabolic disorders that result in an abnormal and uncontrolled rise in blood glucose levels (hyperglycemia) that can have two reasons:

  • due to problems with insulin production;
  • due to problems in the transport of glucose from the blood to the cells, which is called “insulin resistance”.

It is the combination of high levels of glucose in the blood and low levels of glucose in the cells that results in the symptoms and complications of diabetes.

This chronic disease is rapidly expanding in the industrialized world, and in Portugal, according to the National Diabetes Observatory, about 40.7% of the population suffers from pre-diabetes or diabetes. This is one of the most common diseases in the world and its main cause is associated with bad eating habits and obesity.

There are several types of diabetes (pre-diabetes, type 1 diabetes, type 2 diabetes and gestational diabetes), with different causes, however, they all usually present the same type of complications, the most common being lesions in blood vessels, kidneys and in the eyes, neuropathy and peripheral neuropathy, as well as a greater predisposition to infections. The biggest cause of death from diabetes remains, however, heart disease.


The early stage of diabetes is called pre-diabetes. It is similar to diabetes in the sense that blood glucose levels are higher than normal, but still not high enough to qualify as diabetes.

This “phase” should be taken with the utmost seriousness as it is a warning sign of the body that it will be about to develop type 2 diabetes and, consequently, the medical complications derived from the disease. However, this is an essential stage to start treatment, as it is still completely reversible, unlike type 2 diabetes.

Given that the prevalence of diabetes is rapidly expanding throughout the world, and since its symptoms are not very expressive in its initial phase, screening for the disease is recommended in the population at risk of developing type 2 diabetes, in all people with:

  • over 45 years
  • overweight or obesity and waist circumference (in men ≥64cm and in women ≥80cm)
  • sedentary lifestyle
  • family history of diabetes
  • previous gestational diabetes
  • history of cardiovascular disease
  • high blood pressure or high cholesterol
  • consumption of drugs that predispose to diabetes

Type 1 Diabetes Mellitus

Type 1 diabetes is a chronic autoimmune disease, characterized by the almost total or complete inability of the pancreas to produce insulin, hence the only possible response to this disease is the regular administration of insulin. More common to develop in children, adolescents or young adults, it may also develop in adults or the elderly. It is one of the most common diseases in the world, and in Portugal it affects about 1 million people.

Once the pancreas stops producing insulin, the body no longer has its “tool” to carry sugar from the blood to the inside of the cells, which results in an abnormal and uncontrolled rise in blood sugar levels. In this autoimmune disease, it is the body itself that destroys the cells that produce the hormone insulin. The reasons that lead to this abnormal reaction of the body are not known for sure. It is believed that a combination of factors such as genetic characteristics and certain environmental stimuli, such as infections, are the source of the problem.


As this is an autoimmune disease that usually appears in the early stages of life, symptoms usually develop very quickly. They may, however, take longer and appear only in adolescence or early adulthood.

The usual symptoms associated with high glucose and present in all types of diabetes are excessive thirst and hunger, associated with an increase in urinary frequency.

However, in type 1 diabetes, a serious and potentially fatal clinical condition can occur, called diabetic ketoacidosis, in which the body produces excess acid and its initial symptoms are nausea, vomiting, fatigue and abdominal pain, especially in children. If left untreated it can result in coma or even death.

Type 2 Diabetes Mellitus

Although influenced by genetic factors, type 2 diabetes is usually developed due to lifestyle factors and bad eating habits. This is the most common type of the disease, with 9 out of 10 diabetics suffering from type 2 diabetes. It can occur at any age, but is more common in adults who are overweight. It is usually the “second stage” of pre-diabetes.

Type 2 diabetes is characterized by two situations, on the one hand the pancreas abnormally and progressively decreases the production of insulin and, on the other hand, there is a progressive loss of the effectiveness of this same insulin (the so-called “insulin resistance”). The combination of these two reasons leads to an abnormal and uncontrolled increase in glycemia levels.

According to current knowledge, the sequence of events leading to type 2 diabetes is as follows:

  1. As a result of a sedentary lifestyle, bad eating habits and genetic factors, our body begins to develop a resistance to insulin, causing it to progressively lose its effectiveness;
  2. As a form of compensation, the pancreas increases its production of insulin and thus keeps glycemia levels under control, for a while;
  3. In certain people (it is not known for sure why), this increase in insulin production causes the pancreas to begin to fail and stop producing enough insulin to compensate for the insulin resistance and keep blood glucose under control;
  4. As soon as the pancreas cannot withstand the increased production, we begin witness an abnormal and uncontrolled rise in blood glucose and develop type 2 diabetes mellitus.

Although we are not sure about the reasons that lead to pancreas failure in certain people, the reality is that there are risk factors that we can and should be aware of in order to prevent the development of type 2 diabetes: excess weight, low physical activity and increased fat (especially abdominal fat) are factors that are known to be linked to insulin resistance and that can lead to or worsen type 2 diabetes.

Over the years, the patient with type 2 diabetes usually starts to require to administer insulin, as the pancreas stops producing insulin altogether.


We should pay attention to the progressive and subtle symptoms of the disease, so that the diagnosis is made in time and the treatment started as soon as possible. Diagnosing the disease early can, however, be complicated as symptoms can be hidden for years or even decades.

Among the most common symptoms that should create concern are symptoms that are directly associated with the increase in blood sugar:

  • increased urinary frequency – which results from the kidneys trying to filter and eliminate excess blood sugar through urine
  • increased thirst – this is caused by high blood sugar levels and increased urinary frequency
  • increased hunger – as excess calories are eliminated in the urine, the body reacts by “feeling” hungry
  • tiredness or weakness – associated with dehydration caused by increased urinary frequency
  • blurred vision – increased glucose can cause a fluid to seep into the eyes

Gestational Diabetes

During the process of pregnancy a type of diabetes sometimes appears, which we call gestational diabetes. This disorder disappears after childbirth and is mainly due to the fact that during pregnancy the woman’s body prioritize the fetus development at the expense of her own well-being. That is, in pregnancy, all food intake by the woman will be shared with the fetus.

In fact, in some cases, all the glucose and amino acids are sent exclusively to the fetus, depriving the mother of these nutrients, leaving the mother’s metabolism on the basis of fatty acids. The result is an altered state of blood glucose levels in pregnant women who, after fasting, go through a state of hypoglycemia (low blood sugar) and after meals the opposite, a state of hyperglycemia (high blood sugar levels).

If the mother’s clinical condition remains after delivery, that is, if her values ​​do not return to normal, then we are facing a case of type 2 diabetes that was “masked” as gestational diabetes.

Pregnant women who have gone through a period of gestational diabetes are at a higher risk of developing type 2 diabetes in the future, so they should be monitored carefully and regularly by a doctor throughout their lives.


This is a disorder that has no obvious symptoms. For this reason, all pregnant women should have several routine blood tests in order to detect abnormal blood glucose levels from the beginning of pregnancy.

Another measure that should be taken by all pregnant women who have not been diagnosed with gestational diabetes or type 2 diabetes in the blood test. The ingestion of an oral glucose solution (the so-called Oral Glucose Tolerance Test – OGTT), between the 24th and 28th weeks of gestation. By ingesting this supercharged sugar solution diluted in water, doctors are able to measure blood glucose levels in 3 separate blood draws (at 0, 1 and 2 hours after ingestion).

In order to prevent the development of gestational diabetes, pregnant women are advised to eat several times a day and in moderate amounts, thus facilitating digestion and in order to avoid the feeling of heartburn or fullness. And also that they do not deprive themselves of ingesting carbohydrates (bread, pasta, rice), although they should opt for the healthier versions, namely the integral and complete ones.

Once diagnosed with gestational diabetes, it is highly recommended that the pregnant woman performs regular measurements of her blood glucose levels with the health professional assigned to monitor her pregnancy. This way, by repeating the analysis from time to time, the health professional is able to obtain a reliable assessment of the evolution of values. If necessary, through the evaluation of these values, it may be suggested to the pregnant woman to make changes in her diet or even to start taking medication.

The important thing is that blood glucose levels are controlled, for the sake of the health of the mother and the unborn baby.

After delivery, between the 6th and 8th week, a new OGTT is carried out by the mother. In this exam, the doctor will be able to perceive, if the blood glucose levels have not dropped, that the patient actually suffers from type 2 diabetes, since gestational diabetes recedes after delivery.

If the mother shows signs of having type 2 diabetes, before or after delivery, it is important that the baby also undergoes blood tests and medical exams to determine whether its system is able to regulate blood sugar levels effectively.

Complications of Diabetes

A parte do corpo mais afetada pela diabetes é o sistema sanguíneo. Através do estreitamento dos vasos capilares, o fluxo de sangue fica limitado, o que origina um conjunto de possíveis complicações em diversos órgãos, tais como:

  • cérebro – possibilidade de rompimento dos vasos sanguíneos do cérebro originando um AVC
  • olhos – possibilidade de cegueira (retinopatia diabética)
  • coração – possibilidade de causar um ataque cardíaco
  • rins – possibilidade de causar doença renal crónica (nefropatia diabética)
  • nervos – diminuição da sensibilidade nas extremidades, com maior incidência nos pés (neuropatia diabética)

O aumento dos níveis de glicemia é ainda responsável por aumentar a susceptibilidade do organismo a infeções bacterianas e fúngicas.

Prevention and Treatment

The part of the body most affected by diabetes is the blood system. Through the narrowing of blood vessels, blood flow is limited, which leads to a set of possible complications in various organs, such as:

  • brain – possibility of rupture of blood vessels in the brain causing a stroke
  • eyes – possibility of blindness (diabetic retinopathy)
  • heart – possibility of causing a heart attack
  • kidneys – possibility of causing chronic kidney disease (diabetic nephropathy)
  • nerves – decreased sensation in the extremities, most commonly in the feet (diabetic neuropathy)

The increase in blood glucose levels is also responsible for increasing the body’s susceptibility to bacterial and fungal infections.



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