Known as the “silent killer,” diabetes is on the rise in the US (and the world at large) and affects more than 34 million Americans.

Almost 1.5 million new cases of diabetes are recorded each year, an ominous number. In our country it affects 10-12% of the population, translating into the alarming number of 1,000,000 to 1,200,000 of our fellow citizens.

“Diabetes not only affects the heart, kidneys and brain, but also has a prolonged and devastating effect on the immune system. Unregulated, long-term diabetes weakens the immune system and increases susceptibility to disease and infection.

It is proven, and we experienced it during our recent experience with COVID-19, that both long-term good sugar regulation (euglycemia) and above all, good regulation in the first days of infection play a very important role in the favorable outcome of the disease .

A weakened immune system makes infections dangerous for people with diabetes and unfortunately the slightest infection affects them adversely, increasing hospitalization-mortality rates while prolonging their recovery time”, points out Mr. Antonios P. Lepouras Specialist Pathologist – Diabetologist, Director Pathology – Diabetes Clinic and Diabetes Center Metropolitan General and continues:

“The five mechanisms by which diabetes affects the immune system and leads to relative immunosuppression are:

1. Diabetes mellitus reduces the ability of the defense mechanism and white blood cells to reach the site of infection quickly and adequately. It is known to increase the risk of atherosclerosis – a disease in which inflammation within the blood vessels and arteries creates lesions known as atherosclerotic plaque, which in turn leads to hardening and narrowing of the blood vessels. It thus significantly affects the body’s defense capacity and the effort of white blood cells (the cells that fight the disease) to reach the site of infection and stay there. This leads to delayed wound healing, or increased vulnerability to subsequent infections.

2. Chronic hyperglycemia further slows the diffusion of blood through the blood vessels increasing the risk of complications from injuries and infections.

Due to thickening – aging of the blood vessels, a decrease in blood flow to the site of infection is observed. Subsequently, the reduced blood flow drives smaller amounts of nutrients and other healthy cells to the site of the wound than are required for its repair. The skin, a key barrier in the provision of innate immunity loses its elasticity and is not sufficiently capable of providing protection against micro-injuries, inflammations and infections.

An additional delay in wound healing is created making it a “convenient” way for bacteria to enter the body and cause infection.

3. High glucose levels limit and dysregulate neutrophil synthesis.
White neutrophils play an important role in mediating the host’s immune response to bacterial infections. They are the first white blood cells to arrive at the infected area and fight the infection. But high glucose levels limit and dysregulate the synthesis of neutrophils in the body.

Uncontrolled diabetes impairs the production and maturation of neutrophils in the bone marrow, leading to a decrease in their number in the blood. High blood sugar also inhibits the ability of leukocytes to mobilize and reach the site of infection to stimulate apoptosis and the process of removing unwanted cells through programmed cell death.

4. Diabetes mellitus leads to a reduced response of complement, an important factor in the body’s defense mechanism. The complement system is an integral part of our immune system, enhancing the ability of antibodies and phagocytic cells to fight and eliminate disease-causing germs and viruses from our body.

Hyperglycemia, or high blood sugar, causes defects in complement receptors and impairs their ability to induce phagocytosis. This disruption of phagocytosis, in turn, leads to increased microbial activity in the body and enhances susceptibility to infection.

5. High blood sugar gives bacteria the perfect environment to thrive and grow

Hyperglycemia promotes the production of AGEs in the body, which interfere with the body’s natural defense mechanism and limit its ability to fight infection and inflammation. The weakened defense mechanism makes room for more serious bacterial and viral infections when they find a portal of entry into the body (eg injuries-wounds, respiratory system by inhalation, digestive system by ingestion, genitourinary, etc.).

Elevated sugar promotes increased levels of ketone bodies in the body leading to increased acidity in the blood, an environment perfect for germs to thrive uncontrollably.”

What can be done to improve immunity?

“For people with diabetes the best way to stay protected is euglycemia, which is controlling blood sugar levels and keeping them within range. Good blood sugar regulation is also very important, especially at the beginning but also throughout the course of an infection in order to prevent serious complications and problems” and he adds: “Of course, it is equally necessary:

– Stop smoking

– Watch out for weight: Obesity, or being overweight, puts you at high risk for developing type 2 diabetes (the most common type) while damaging the immune system, increasing inflammation and worsening the severity of infections as well as other chronic diseases. Obese people without health problems during the COVID-19 pandemic had the same or higher risk of intubation and death as the high-risk group such as people with diabetes.

– Regular exercise: Regular physical activity helps the body use insulin effectively, helping to regulate it, lowering blood sugar levels and significantly improving the immune system. Good physical condition (fitness), apart from being a necessary component of longevity and well-being, has been shown in many studies to improve immunity as well as the outcomes and the duration of illness in all infections.

– Proper diet: A proper Mediterranean diet with fruits, unprocessed carbohydrates e.g. whole grain foods (no excess, but in moderation), vegetables, low-fat proteins e.g. dairy products, fish, meat (goat, beef, poultry, etc.) cooked at low temperatures, proven to help according to studies. Attention, overconsumption of vitamins does not help, e.g. vitamin C or D, or various supplements advertised as immune boosters, on the contrary, can cause serious complications and damage to the body.

Let’s not forget that physical well-being is together with mental well-being and a positive life attitude, the two sides of the same coin, an effective, simple and at the same time very difficult recipe for improving not only our immune system, but also our quality of life “, concludes Mr. Lepouras.