Cushing's Syndrome - Manifestations, Therapy, and Suitable Diet

Cortisol is a hormone whose precursor is cholesterol. It belongs to a group of glucocorticosteroid hormones produced in the adrenal cortex. The amount of cortisol produced is determined by the concentration of adrenocorticotropic hormone, also known as ACTH. The latter is produced in the pituitary gland, specifically in its anterior lobe. In the adrenal cortex, there are receptors that respond to this hormone, thus stimulating the production of cortisol. This hormone is crucial for the normal functioning of the body. Its presence helps the organism to respond to stress and threats. When a factor that can threaten life or health appears, the organism triggers a stress response. First, there is an activation of the sympathetic nervous system and the release of adrenaline, leading to an acceleration of the heart rate and an increase in blood flow to the muscles. This is followed by a widening of the respiratory pathways, an increase in glucose and fatty acid levels in the blood. Subsequently, there is a release of cortisol, which keeps the body on alert. When the threat is over, the cortisol level drops. In the past, such a stress response was very useful. Today, however, due to psychological pressure and other factors, chronic stress can lead to a persistent increase in cortisol levels, which can have negative effects on the body.

Cortisol impacts the metabolism of proteins, fats, and carbohydrates directly or through the stimulation of other hormones' actions.

Enhancement of gluconeogenesis, which is the production of glucose from amino acids in the liver. The hormone enhances the release of amino acids from tissues, particularly from muscles. As a result, there is an increase in the breakdown of proteins, including muscle, bone, and connective tissue. This can lead to muscle loss or a decrease in bone density. Cortisol also inhibits the action of insulin. In combination with increased glukoneogenesis, this can lead to an increase in blood glucose levels over the long term, which can lead to increased stress on body tissues, including muscle and bone tissue. Enhancement of lipolysis, which is the breakdown of fat tissue and the release of fatty acids into the bloodstream. In the short term, this can be a beneficial process, as fatty acids can be converted into energy or involved in biochemical processes and support glukoneogenesis. However, prolonged cortisol action can lead to hyperlipidemia. Enhancement of appetite. Stimulation of the release of hydrochloric acid in the stomach. Anti-inflammatory effect. However, in the case of prolonged, excessive cortisol action, this effect can decrease and even exhibit a pro-inflammatory effect. All of the above-mentioned effects of cortisol are components of the stress response. The stress response has been shaped by natural selection and enabled the body to survive in changing environmental conditions. Thanks to the increased glucose level and other energy sources, the body is prepared for intense physical effort and quick reaction. However, hypercortisolism is a pathological condition, and prolonged exposure to this compound can lead to numerous complications.

According to the National Institute of Health, Cushing's Syndrome most commonly occurs in people in their 20s and 50s with inflammatory conditions such as arthritis, obesity, asthma. Glycosteroid syndrome is a condition in which the body is over-exposed to cortisol, regardless of the source of the hormone. It may be associated with the use of glucocorticoids, e.g. prednisone, used in inflammatory conditions such as rheumatoid arthritis, acne and asthma.. Glycocorticosteroids are also used in transplants – they reduce the intensity of the body's immune response, which reduces the risk of transplant rejection.. Cushing's disease is caused by an overproduction of cortisol, which can be due to tumors of the pituitary gland (adenomas) that secrete ACTH (adrenocorticotropic hormone), tumors in other parts of the body that also have the ability to produce ACTH (most often in the course of small cell lung cancer, less often in insulinomas) or tumors of the adrenal cortex. Hypercorticosteroids are responsible for the appearance of characteristic symptoms, which can lead to: – muscle mass and strength loss (due to increased amino acid breakdown, including muscle, for glucose production); – the development of a so-called „bull neck“, i.e. the accumulation of fat tissue in the neck.. Fat tissue can also accumulate in other places, which can lead to the development of abdominal fat.. Another characteristic symptom is the „moon face“; – increased susceptibility to injuries and ulcers; – the development of stretch marks due to impaired collagen production; – a tendency to fungal infections; – increased thirst and frequent urination (which may be due to disorders of blood sugar levels); – increased appetite; – emotional lability; – stomach and duodenal ulcers (due to increased production of gastric acid).

In identifying Cushing's syndrome, the following procedures are primarily employed: 24-hour analysis of free cortisol in urine. This involves collecting urine samples and performing a measurement of the hormone level. The threshold values depend on the norms used in individual laboratories. Another method is the measurement of cortisol levels in the evening in serum or saliva. A result > 145 nmol/l in serum or > 4 nmol/l in saliva indicates an increased hormone level. In physiological conditions, the cortisol level in healthy individuals peaks in the morning and then decreases during the day. Another procedure is the dexamethasone suppression test. It requires taking 1 mg of dexamethasone in the evening and performing a measurement of the cortisol level in the serum the next morning. Dexamethasone is a synthetic glucocorticoid. In physiological conditions, the body should respond to this compound with a decrease in cortisol production. If, in the test after administration of the drug, the cortisol level does not decrease, the presence of Cushing's syndrome is suspected. The examination may give a false-positive result if there is an inflammatory disease, depression, alcoholism, or excessive stress. A false-negative result may be caused by taking medications such as phenobarbital or phenytoin.

"The treatment of Cushing's syndrome depends on the cause. If it is triggered by glucocorticoid use, the doctor usually chooses smaller doses or changes their dosing schedule so that the side effects are less severe. Pituitary adenomas that produce ACTH are most often surgically removed, which is one of the most effective methods. After the removal of the tumor, the ACTH level usually decreases twice below the normal level, which requires the intake of synthetic glucocorticoids, usually for a period of one to two years after the operation, although this period may sometimes be longer. If there are contraindications for surgery, radiotherapy is used. Surgical procedures, radiotherapy, chemotherapy, or immunotherapy are used in the treatment of ACTH-producing tumors, and the selection of the appropriate method depends on the type and location of the tumor. Since hypercortisolism is also the cause of metabolic disorders, adherence to a suitable diet is very important."

Cushing's syndrome is often associated with glycaemic disorders and hyperlipidemia, which is a direct consequence of the action of cortisol, leading to increased glucose production and elevated blood glucose levels, as well as the release of fatty acids. Moreover, Cushing's syndrome increases the risk of osteoporosis and hypertension, making it essential to adhere to key principles in the diet, such as limiting carbohydrate intake, increasing protein intake, and reducing fat intake.

In order to support the body in maintaining steady blood glucose levels, it is recommended to limit the intake of products high in simple sugars that cause sudden increases in blood glucose. Therefore, it is advisable to avoid products with added sugar, baked goods, fruit juices, sweetened beverages, and products high in simple sugars. It is worth focusing on whole-grain products such as whole-grain bread, whole-grain pasta, buckwheat groats, or millet. In addition, eating meals regularly every 3-4 hours also helps maintain stable blood glucose levels.

Fats derived from animals and trans fatty acids may have a negative impact on the lipid profile. Reducing the consumption of these fats can help lower triglyceride and LDL cholesterol levels. Saturated fatty acids should be replaced with unsaturated fats, particularly those of plant origin. Therefore, intake of fatty meats, butter, bacon, pastries rich in trans fats, hard bone fat margarines, and fast food products should be limited. However, sources of unsaturated fatty acids include plant oils (e.g., rapeseed, flaxseed, olive oil), which are best consumed raw, such as in salad dressing, and fish.

Fiber actively impacts the inhibition of fat absorption in the intestines. Fiber-rich products encompass vegetables, whole-grain baked goods, grits – such as buckwheat, millet, bran, barley, brown rice, whole grain pasta. Conversely, products manufactured from white flour are devoid of a substantial portion of this valuable component. An integral element of a healthy diet is vegetables – not only a source of fiber but also valuable polyphenolic compounds, vitamins, and minerals. It is advised to consume 5 portions of vegetables every day.

Due to the increased risk of osteoporosis, it is recommended to consume products that are the best source of calcium, such as natural yogurts, kefirs, milk, cottage cheeses (3 servings per day)... The supply of vitamin D through diet alone is very difficult... Therefore, supplementation is recommended from September to April, that is, during periods of less intense sun exposure... Exercise is also an essential part of a healthy lifestyle... To prevent muscle weakness and muscle mass loss, it is worth engaging in physical activity that is tailored to one's abilities... Regularity is key... At the same time, it is important not to forget to consume enough protein in the diet – not only of animal origin... In the three main meals, there should be a source of this macronutrient, such as dairy products, lean meat, eggs, legumes... Although diet is not the main component of treatment for Cushing's syndrome, proper nutrition is an important part of therapy aimed at improving glycemia, lipid profile, and maintaining a healthy weight... Obesity associated with this hormonal disorder requires measures to reduce body weight... The introduction of the proposed rules should bring results, and in case of their absence, it is worth discussing the diet plan with a dietitian who can help correct errors.