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Vitamin D deficiency

Vitamin D, often referred to as the “sunshine vitamin” or even the “elixir of life”, is actually a fat-soluble prohormone that plays a fundamental role in maintaining the health and proper functioning of the human body. Its importance goes far beyond the commonly known function of supporting bone health. Unfortunately, vitamin D deficiency is a widespread global health problem, potentially affecting more than 90% of the population, including a significant proportion of men. This alarming statistic suggests that standard, natural sources of this vitamin – skin synthesis under the influence of the sun and diet – are insufficient for most of the inhabitants of our country. The universality of this phenomenon indicates that it is not only an individual problem resulting from negligence, but rather a population-related issue, conditioned by geographical factors and lifestyle, requiring a conscious approach and appropriate prevention strategies.

Vitamin D3 – An Essential Ingredient for Every Man’s Health

Vitamin D has functions in the body that go far beyond the classic role in calcium and phosphate metabolism. It is a compound with a broad, pleiotropic effect, which means that it affects many different, seemingly unrelated processes and systems in the body. It controls the expression of at least 200 genes, and the presence of its receptors (VDR – vitamin D receptor) has been found in almost all tissues of the body, which proves its comprehensive impact on health. Understanding the complex role of vitamin D, the causes of its deficiency and the potential health consequences, especially in the context of the male body, is crucial for making informed decisions about prevention and possible supplementation.

How Does Vitamin D Affect the Male Body? What is vitamin d

Vitamin D has a number of key functions in the male body, affecting bone health, muscle strength, immune function, as well as aspects related to hormonal balance and fertility.

Role in bone, muscle, and immunity health

The basic and best known function of vitamin D is the regulation of calcium and phosphate metabolism. It is responsible for the absorption of calcium and phosphate from the gastrointestinal tract and their proper use, which is essential for proper mineralization, development and maintenance of healthy, strong bones and teeth throughout life. As a result, it prevents the development of rickets in children and osteomalacia (softening of the bones) and osteoporosis in adults, including men.

Vitamin D is also essential for proper muscle function. It affects the maintenance of their strength, fitness and coordination, which is important not only for general physical performance, but also for the prevention of falls and related fractures, especially in the elderly. Vitamin D deficiency can lead to muscle weakness, muscle pain (myalgia) and cramps. It is worth noting the synergistic effect of vitamin D on the musculoskeletal system – it not only strengthens the bone structure by regulating calcium metabolism, but also improves the function of muscles that stabilize the skeleton and protect against falls. This dual mechanism provides much more effective protection against osteoporotic fractures than affecting the bone or muscles alone.

Another key role of vitamin D is its effect on the immune system. It has an immunomodulatory effect, which means that it regulates the body’s immune response. It strengthens both innate and acquired immunity by stimulating immune cells to produce antibacterial proteins (e.g. cathelicidins) and regulatory cytokines. It helps the body fight bacterial and viral infections more effectively, reducing susceptibility to colds, flu or respiratory infections. In addition, vitamin D contributes to the extinguishing of excessive inflammatory reactions, which is important in the prevention of inflammatory diseases. This immunomodulatory aspect may be particularly important for physically active men. Intense exercise can temporarily weaken the immune system, creating the so-called “immune window” of increased susceptibility to infections. Adequate vitamin D levels, by supporting both muscle function and immunity, can contribute to faster regeneration and reduce the risk of post-exercise infections, which allows you to maintain the continuity of training.

Vitamin D3 deficiency and testosterone and male fertility

A growing body of evidence points to a potential link between vitamin D levels and the functioning of the male endocrine and reproductive systems. Observational studies suggest that low blood levels of vitamin D often co-occur with reduced testosterone levels in men. The mechanism of this phenomenon is not fully understood, but it is suspected that vitamin D may play a role in testosterone production. Vitamin D receptors (VDRs) are located in the Leydig cells in the testes, which are responsible for the synthesis of this hormone. In addition, vitamin D can affect the levels of sex hormone-binding globulin (SHBG), a protein that transports testosterone in the blood. Lowering SHBG levels by vitamin D could potentially increase the pool of free, biologically active testosterone.

Some intervention studies have shown that vitamin D supplementation in men with vitamin D deficiency can lead to a significant increase in testosterone levels. However, the results are inconclusive – other studies, such as those conducted in men on hemodialysis with vitamin D deficiency, did not show a significant change in testosterone levels after three months of supplementation, despite achieving normal vitamin D levels. the dose used or the duration of supplementation. Therefore, it cannot be clearly stated that vitamin D supplementation guarantees an increase in testosterone levels in every man, and the decision to implement it should be made individually.

Vitamin D also appears to play a vital role in male fertility. Studies indicate that it affects sperm quality, including sperm count, motility, and morphology, and thus their ability to fertilize an egg. VDR receptors are present in various cells of the male reproductive system, including the sperm themselves, granulosa cells in the testes, and the pituitary gland. Vitamin D is involved in processes crucial for sperm function, such as capacitation (becoming fertilizable) and acrosomic reaction (allowing the egg to enter). The effect of vitamin D on fertility can therefore be twofold: direct, by affecting the sperm themselves, and indirect, by potentially affecting testosterone levels, which is essential for the process of spermatogenesis. Additionally, some sources suggest that vitamin D may also affect male libido.

Vitamin D3 Deficiency in Men in Poland: Causes and Risk Factors

The prevalence of vitamin D deficiency in Poland is due to a combination of geographical, environmental and lifestyle factors that limit the natural production of this vitamin in the skin and its supply with the diet.

The problem of insufficient sun exposure

The main source of vitamin D for humans, covering up to 80-90% of the daily requirement, is its synthesis in the skin under the influence of solar radiation, specifically its UVB component. Unfortunately, in Poland, due to its geographical location, effective skin synthesis is only possible from late spring to early autumn, usually from April/May to September. For this process to be effective, adequate sun exposure is necessary – it is recommended to stay in the sun for about 15-45 minutes (depending on age and skin complexion) between 10:00 and 15:00, with at least 18% of the body surface (e.g. forearms and lower legs) uncovered and without the use of sunscreen.

In practice, however, many factors further limit the possibility of sufficient skin synthesis of fat-soluble vitamins, including vitamin D. These include: time of day, cloudiness, air pollution, as well as the modern lifestyle, characterized by spending most of the time indoors (office work, home). An important factor is also the widespread use of creams with a UV filter. Although essential for protection against the harmful effects of the sun and the prevention of skin cancer, these filters significantly block UVB radiation responsible for the production of vitamin D – SPF 8 reduces synthesis by about 98%, and SPF 15 by up to 99.9%. Therefore, a peculiar paradox arises – taking care of skin protection from the sun is in conflict with the natural mechanism of obtaining vitamin D. For people who consciously use sun protection, relying solely on the sun as a source of vitamin D becomes impossible, which further emphasizes the importance of other sources, including supplementation.

Diet and vitamin D levels

The second source of vitamin D is diet, but its share in covering the daily requirement is much smaller and is estimated at only about 10-20%. Natural dietary sources of vitamin D are relatively limited. It is most contained in oily sea fish, such as salmon (especially wild salmon), herring, mackerel, eel, sardines, as well as cod liver oil, i.e. cod oil. Smaller amounts are found in egg yolks, cheese, butter and some mushrooms (e.g. champignons, shiitake, maitake – these, however, contain mainly vitamin D2, i.e. ergocalciferol, while the D3 form, cholecalciferol, of animal origin and synthesized in the skin, is considered more effective in raising vitamin D levels in the blood). Cow’s milk, contrary to some opinions, naturally contains small amounts of vitamin D, unless it is artificially enriched (fortified) with it, which is not a common practice in Poland.

In order to cover the daily requirement for vitamin D through diet alone, it would be necessary to consume unrealistically large amounts of these products, e.g. several hundred grams of fatty fish or several dozen eggs per day. In addition, the best dietary sources, i.e. oily sea fish, are not consumed by Poles in sufficient quantities, which is due to both their price and availability (especially fresh, good quality), as well as individual taste preferences. All this makes relying solely on diet to ensure optimal vitamin D levels virtually impossible for most men in France.

Who is particularly vulnerable? (age, obesity, lifestyle, diseases)

There are groups of men in whom the risk of vitamin D deficiency is particularly high. These include:

• Older men: After the age of 65-75, the skin’s ability to synthesize vitamin D under the influence of the sun significantly decreases, and its metabolism in the body changes. Therefore, seniors are recommended to supplement throughout the year, often in higher doses.
• Overweight and obese men: People with a body mass index (BMI) above 30kg/m2 are more likely to be deficient, because vitamin D, as fat-soluble, is stored (sequestered) in excess adipose tissue, which reduces its availability to the rest of the body. Such men often require higher doses of supplementation, up to twice as much as people of normal weight.
• Men with a specific lifestyle: Employees working indoors most of the day, working night shifts, people deliberately avoiding the sun or covering a large area of their skin with clothing.
• Men with dark skin: Melanin, the skin’s pigment, acts as a natural sunscreen, reducing the production of vitamin D.
• Men with chronic diseases: Especially kidney and liver diseases (organs crucial for vitamin D activation), inflammatory bowel diseases (e.g. Crohn’s disease, ulcerative colitis), celiac disease, cystic fibrosis, fat malabsorption syndromes, some autoimmune diseases, granulomatous diseases (e.g. sarcoidosis), as well as cancer patients. Men who have undergone gastrectomy are also at risk of malabsorption.
• Men taking certain medications: Antiepileptic drugs, glucocorticoids (used e.g. in inflammatory and autoimmune diseases), antiretroviral drugs (used to treat HIV/AIDS), some anticancer drugs, antibiotics (rifampicin, isoniazid), antifungal drugs (ketoconazole) can interfere with the metabolism or absorption of vitamin D.
• Men on elimination diets: A vegan diet (if not properly supplemented) or diets very low in fat can promote deficiencies.

It is worth noting that many men may have several of these risk factors (e.g. office work, age over 65 and overweight). Each of these factors separately increases the likelihood of deficiency, and their accumulation can lead to very deep deficits that require careful diagnosis and treatment. In addition, men who are being treated for chronic diseases (e.g., kidney, liver, intestines) or taking certain medications may not be aware that their underlying medical condition or treatment directly increases the risk of vitamin D deficiency.

How to recognize vitamin D deficiency? Symptoms in Men

Symptoms of vitamin D deficiency are often insidious – they can be non-specific, easy to overlook or attribute to other causes, such as stress, overwork or the natural aging process. However, awareness of potential warning signals may prompt further diagnostics.

The most common warning signs

The most commonly reported symptoms that may suggest vitamin D deficiency include:

• Chronic fatigue, lack of energy and general weakness: A feeling of constant exhaustion, rapid fatigue even after little effort, lack of vitality and motivation to act.
• Bone and joint pain: Generalized or localized bone pain, often described as “breaking in the bones”, pain in the back (especially the lower spine), hips, legs, as well as joint pain. It is worth noting that back pain can be misinterpreted as the result of a sedentary lifestyle or overload.
• Muscle pain and weakness: Muscle pain (myalgia), feeling of muscle stiffness, cramps (especially in the calves), general muscle weakness, difficulty climbing stairs or getting up from a sitting position.
• Reduced immunity and frequent infections: Increased susceptibility to colds, flu, upper and lower respiratory tract infections, longer recovery time after infection.

The prevalence of ailments such as fatigue or back pain in modern society means that they are often underestimated and attributed to other factors. This can mask vitamin D deficiency as a potential cause of these problems, delaying proper diagnosis and management. Therefore, it is worth paying special attention to these symptoms, especially if they occur together, persist for a long time or intensify in autumn and winter.

Less obvious symptoms

In addition to the most common symptoms, vitamin D deficiency can also manifest itself in less typical ways:

• Depressed mood and depressive states: There is a link between low vitamin D levels and an increased risk of mood disorders, including depression, depression, depression and anxiety. Vitamin D affects the production of important neurotransmitters in the brain, such as serotonin and dopamine, which regulate mood. This aspect is particularly important in the context of growing mental health problems in men, where vitamin D supplementation could be an underestimated element of therapy support.
• Sleep problems: Difficulty falling asleep, insomnia, restless sleep.
• Excessive hair loss: Vitamin D deficiency can disrupt the normal hair growth cycle, leading to weakening and increased hair loss. Although this problem is more often described in women, it can also affect men.
• Slow wound healing: Vitamin D plays a role in the regeneration processes of the skin and tissues. Its deficiency can slow down the healing of post-traumatic and post-operative wounds, and even minor cuts or wounds after dental procedures.
• Concentration problems and headaches: Difficulty concentrating, a feeling of “brain fog”, cognitive decline, and headaches can all be associated with vitamin D deficiency.
• Other, less common symptoms: Irritability, skin problems (e.g. aggravation of acne, atopic dermatitis, psoriasis), appetite disorders, diarrhoea, excessive sweating, deterioration of hearing, dental problems (increased susceptibility to caries, gum disease, tooth loss).

It is worth remembering that symptoms such as hair loss or skin problems can have many causes. However, vitamin D deficiency can be a coexisting or exacerbating factor in these problems, especially in the context of vitamin D deficiency in children. Supplementing the deficiency may not solve the problem completely, but it may improve the response to other therapies used, e.g. dermatological. Recognizing these less common symptoms can be the key to early detection of deficiency, especially when the classic symptoms are not very severe.

Serious Effects of Vitamin D Deficiency on Men

Long-term vitamin D deficiency can lead to a number of serious health consequences, going beyond pain or fatigue. It negatively affects many systems and organs, increasing the risk of developing the effects of vitamin D deficiency.

Male osteoporosis – the silent thief of bones

Although osteoporosis is more often associated with postmenopausal women, it also affects men, and vitamin D deficiency is one of the main risk factors for its development in this group. Vitamin D is essential for the proper absorption of calcium – the basic building block of bones. Its lack leads to insufficient mineralization of bone tissue, which results in its weakening, reduced density (osteopenia and then osteoporosis) and softening (osteomalacia). Weakened bones become more susceptible to fractures, even with minor injuries or falls, which may be the result of vitamin D deficiency. low-energy or osteoporotic fractures, which most often affect the spine, hip or wrist.

An adequate supply of vitamin D, often in combination with calcium and vitamin K2 (which helps direct calcium to the bones), is a key element in the prevention and treatment of osteoporosis in men. Vitamin D supplementation may contribute to reducing the risk of falls and fractures , although the results of some large clinical studies evaluating the effect of vitamin D supplementation alone on fracture rates are inconclusive. Men with gastrointestinal diseases leading to malabsorption (e.g. after bariatric surgery, gastrectomy , inflammatory bowel diseases) and men chronically taking certain medications, e.g. glucocorticoids, are particularly at risk of developing osteoporosis. In these groups, regular monitoring of bone density and vitamin D levels is particularly important.

Risk of cardiovascular disease

A growing body of scientific evidence indicates a link between vitamin D deficiency and an increased risk of developing cardiovascular diseases. Vitamin D receptors are found in many cells of the circulatory system, including vascular smooth muscle cells, endothelial cells (the lining of the vessels), and heart muscle cells (cardiomyocytes).

Vitamin D can affect the cardiovascular system through several mechanisms. It is involved in the regulation of blood pressure, m.in. by inhibiting the renin-angiotensin-aldosterone (RAA) system, which plays a key role in the pathogenesis of hypertension. It also affects the proper functioning of the vascular endothelium, the dysfunction of which is an early stage of atherosclerosis development. In addition, vitamin D has anti-inflammatory and antioxidant properties, can affect the processes of calcification of blood vessels and the lipid profile (some studies suggest a relationship with the level of “good” HDL cholesterol). Vitamin D deficiency was more often observed in patients with hypertension, coronary artery disease, myocardial infarction, heart failure and atherosclerosis. Some studies even suggest a cardioprotective effect of vitamin D, and its deficiency has been associated with the risk of left ventricular hypertrophy.

However, it is important to note that although the observational association between low vitamin D levels and heart disease is strong, the results of intervention studies evaluating the benefits of vitamin D supplementation in the prevention of cardiovascular events are less convincing and often do not show significant benefits. This may suggest that low vitamin D levels are more of a marker of overall poorer health, which is especially concerning in the case of vitamin D deficiency in children. related to obesity, less physical activity, poorer diet) than a direct cause of heart disease, or that the mechanisms are more complex. What’s more, there have been some concerns that vitamin D supplementation, especially when combined with calcium, may potentially worsen the progression of aortic stenosis in some patients. This complexity highlights the need for individual risk-benefit assessment and avoidance of routine vitamin D supplementation to prevent heart disease without consulting a physician, especially in patients with pre-existing cardiac conditions.

Relationship with diabetes and insulin resistance

Vitamin D deficiency has also been linked to an increased risk of developing metabolic disorders, including insulin resistance and type 2 diabetes. Vitamin D appears to play a role in maintaining normal carbohydrate metabolism. It affects the functioning of pancreatic β cells, which are responsible for the production and secretion of insulin. It may also improve the sensitivity of peripheral tissues (such as muscle and adipose tissue) to insulin, m.in. by affecting the expression of the glucose transporter GLUT4. In addition, vitamin D has anti-inflammatory properties, and chronic low-grade inflammation is one of the factors contributing to the development of insulin resistance.

Men with obesity are a group particularly vulnerable to vitamin D deficiency as well as to the development of metabolic syndrome and type 2 diabetes. Maintaining optimal vitamin D levels in this group may be part of a comprehensive strategy to reduce metabolic risk, potentially acting on pathways related to insulin resistance and inflammation.

Vitamin D and Prostate Cancer Risk

The link between vitamin D and the risk of developing prostate cancer is the subject of intense research, but the results are currently inconclusive and sometimes contradictory.

On the one hand, some studies suggest that low levels of vitamin D may be associated with an increased risk of prostate cancer, especially more aggressive forms. It has also been observed that low vitamin D levels at the time of diagnosis may be associated with a worse prognosis and higher mortality. Mechanisms of potential anticancer activity of vitamin D include inhibition of uncontrolled proliferation (multiplication) of cancer cells, promotion of their differentiation (maturation) and induction of apoptosis (programmed cell death).

On the other hand, there are studies that have not shown an association between vitamin D levels and the risk of prostate cancer , and even those that suggest that very high concentrations of vitamin D may be associated with an increased risk of this cancer. This apparent contradiction may indicate a complex, potentially non-linear relationship (the so-called vitamin D test). U-curve), where both too low and too high levels of vitamin D can be unfavorable, and it is optimal to maintain the concentration in the physiological range (e.g. 30–50ng/ml).

Vitamin D supplementation has also been studied as an adjunct to the treatment of prostate cancer, e.g. in order to slow down tumor growth (measured by the level of PSA – prostate-specific antigen) or to alleviate the side effects of cancer therapy, treatment of vitamin D deficiency is recommended. It is possible that vitamin D plays a different role in preventing cancer initiation and another in modulating the progression of an already existing disease – its deficiency may promote a more aggressive course of cancer, while the effect on the risk of developing the disease itself is less certain.

In conclusion, the link between vitamin D and prostate cancer is still not fully understood and requires further research. Currently, there is not enough evidence to recommend vitamin D supplementation for the prevention or treatment of prostate cancer beyond the standard indications for correcting deficiencies.

Effects on the immune system and autoimmune diseases

As mentioned earlier, vitamin D plays an important role in regulating the immune system. Its deficiency is associated with an increased risk of developing or exacerbating the course of autoimmune diseases, in which the immune system attacks the body’s own tissues. These include, m.in, multiple sclerosis (MS), type 1 diabetes, rheumatoid arthritis (RA), inflammatory bowel diseases (Crohn’s disease, ulcerative colitis) and autoimmune thyroid diseases (e.g. Hashimoto’s disease).

Vitamin D, through its immunomodulatory effect, has the potential to inhibit the overactive reactivity of the immune system and alleviate the inflammatory processes underlying these diseases. Therefore, maintaining normal vitamin D levels may play a role in the prevention of autoimmune diseases, and in people who are already ill – be an element supporting standard treatment. Men suffering from autoimmune diseases (which, although statistically more common in women, also occur in men) should take special care of the appropriate vitamin D status, as its deficiency can potentially negatively affect the course of the underlying disease.

Vitamin D Level Test: When and How to Check?

Given the prevalence of vitamin D deficiencies and their potential health consequences, the key question is how to reliably assess vitamin D levels in the body.

25(OH)D test – the gold standard

The best and widely accepted way to assess the body’s supply of vitamin D is to determine the concentration of its main circulating metabolite – 25-hydroxyvitamin D (calcidiol), determined as 25(OH)D – in blood serum. This metabolite has a relatively long half-life (about 2-3 weeks , other sources report several weeks ), which well reflects the general status of vitamin D in the body, coming both from skin synthesis and from diet or supplementation. The determination of the active form of vitamin D – 1,25-dihydroxyvitamin D (1,25(OH)2D, calcitriol) – has a much shorter half-life (a few hours ) and is less useful for assessing the overall supply of the body, and its level is tightly regulated by other hormones (e.g. parathyroid hormone) and can be normal even with a significant deficiency of 25(OH)D.

Testing the level of 25(OH)D is recommended before starting supplementation, especially in doses higher than prophylactic, in order to select the appropriate initial dose. This study is also used to monitor the effectiveness of deficiency treatment and possible dosage adjustment. However, it should be remembered that this test in Poland is usually not reimbursed by the National Health Fund as part of primary health care (POZ) and the patient must cover its cost on their own. This is a barrier, especially given the prevalence of the deficiency problem and expert recommendations for monitoring vitamin D levels.

Interpretation of results: Polish standards (ng/ml, nmol/l)

The results of the 25(OH)D level test are usually given in two units: nanograms per milliliter (ng/mL) or nanomoles per liter (nmol/L). It is worth remembering the approximate conversion rate: 1ng/ml≈2.5nmol/l.

According to current Polish and international guidelines, the interpretation of the results of blood 25(OH)D concentration in adults is as follows:

Interpretation of Vitamin D (25(OH)D) Blood Levels

Procurement Status	Concentration (ng/mL)	Concentration (nmol/L)	Recommendations (general according to Polish guidelines )
Severe Deficiency / Deficit	< 20	< 50	It requires pharmacological treatment with therapeutic doses under medical supervision.
Insufficient / Suboptimal	20–30	50–75	It indicates the need for a moderate increase in the daily dose of vitamin D (supplementation).
Optimal / Target Level	30–50	75–125	Levels that ensure optimal, pleiotropic effect of vitamin D. Prophylactic dose or current management should be maintained.
High level	> 50–100	> 125–250	It may require a reduction in the supplementation dose if the concentration is close to the upper limit.
Potentially toxic level	> 100	> 250	It requires discontinuation of supplementation and medical consultation.
Toxic level	> 200	> 500	It requires medical intervention to treat the symptoms of toxicity.

How to Effectively Supplement Vitamin D? Sun, Diet and Supplementation

Correcting vitamin D deficiency and maintaining its optimal level usually requires a combination of several strategies, including conscious use of the sun, proper diet and, in most cases in Polish conditions, regular supplementation.

Using the sun wisely

Skin exposure to UVB solar radiation remains the most effective natural way to produce vitamin D. To benefit from this mechanism in Polish climatic conditions, it is recommended to:

• From May to September, stay in the sun for about 15-45 minutes (the time depends on age, skin complexion and sun intensity) between 10:00 and 15:00.
• Exposure of at least 18% of the body surface (e.g. forearms and lower legs).
• Do not use sunscreen on exposed parts of the body during this time.
• People with darker skin need a longer exposure time than people with fair skin.
• Sunburn, which is harmful to the skin, should be absolutely avoided, especially in the context of excess vitamin D.

However, it is important to remember the limitations of this method: it is only effective for part of the year, and its effectiveness depends on many variable factors (weather, air pollution, individual characteristics). In addition, the need to avoid UV filters during exposure is contrary to the recommendations for skin cancer prevention. Therefore, relying solely on the sun is difficult to realize and control in practice for many people.

Products rich in vitamin D

Although the diet covers only a small part of the vitamin D requirement, it is worth including products that are a natural source of it in the menu.

Approximate Vitamin D3 Content in Selected Foods

Food Product	Approximate Vitamin D3 Content (IU / 100g or per serving)
Fresh eel	1200 IU / 100g
Wild salmon (fresh/baked/cooked)	600–1000 IU / 100g
Herring in oil	Ok. 808 IU / 100g
Marinated herring	Ok. 480 IU / 100g
Farmed salmon (fresh/baked/cooked)	100-540 IU / 100g (Wide Range)
Mackerel (cooked/baked/smoked)	Ok. 150-250 IU/100g
Canned sardines (in oil/tomato sauce)	200–300 IU / 100g
Canned tuna	Ok. 200 IU / 100g
Cod liver oil (cod liver oil)	up to 1000 IU/teaspoon (5 ml)
Egg yolk	Ok. 20-54 IU / 1 piece (depending on source)
Cheese	7.6–28 IU / 100g
Extra butter	Ok. 30 IU / 100g (approx. 0.76 μg / 100g according to vitamin D content). )
Mushrooms (fresh, not exposed to UV)	Ok. 4-8 IU / 100g (approx. 1.94 μg / 100g according to vitamin D content). )
Mushrooms (exposed to UV)	Ok. 150-450 IU/100g (depending on exposure)
Cow’s milk 3.2% (non-fortified)	Ok. 2-5 IU/100 ml (0.4–1.2 IU/100ml by )

Conversion rate: 1μg=40IU. The data in the table are indicative and may vary depending on the source, origin of the product, breeding/cultivation and treatment. Data sources:.

As you can see in the table, even eating foods considered to be rich in vitamin D (except for fish oil and some species of fish in large quantities) does not guarantee that the daily requirement for vitamin D3 levels is covered. Therefore, diet should be treated as an important, but still supplementary source of vitamin D.

Vitamin D supplementation – Polish recommendations for men

In Polish geographical conditions and with the modern lifestyle, vitamin D supplementation is considered to be the key and surest way to ensure its optimal levels throughout the year or during periods of insufficient exposure to the sun. The current (for 2023/2024) Polish guidelines for prophylactic cholecalciferol (D3) supplementation for adult men are as follows:

• Men aged 19-65: The recommended dose is 1000–2000 IU (25–50 μg) per day. Supplementation should be carried out at least from September/October to April/May. However, if sufficient skin synthesis is not ensured during the summer (e.g. due to indoor work, the use of UV filters), supplementation throughout the year is recommended. The dose should be adjusted according to body weight and the supply of vitamin D in the diet.
• Men aged 65–75 (seniors): The recommended dose is 1000–2000 IU (25–50 μg) per day throughout the year, due to the reduced efficiency of skin synthesis. The dose should be adjusted according to body weight and dietary supply.
• Men over 75 years old (older seniors): The recommended dose is 2000–4000 IU (50–100 μg) per day throughout the year, due to further deterioration of skin synthesis and altered metabolism of vitamin D. The dose should be adjusted according to body weight and dietary supply.
• Men with obesity (BMI > 30kg/m2): Due to the sequestration of vitamin D in adipose tissue, it is recommended to use double the dose recommended for age, i.e. up to 4000 IU (100 μg) per day, throughout the year.

If vitamin D deficiency is found in a blood test (25(OH)D<concentration of 20ng/ml), it is necessary to initiate treatment with therapeutic doses that are much higher than prophylactic doses (e.g. 7000–10,000 IU per day for a period of 1-3 months). Such treatment should only be supervised by a physician and monitored by blood tests to assess efficacy and avoid overdose. The aim of the therapy is to achieve optimal vitamin D levels for children. 25(OH)D (30–50ng/ml) followed by switching to a maintenance (prophylactic) dose.

Important tips for supplementation:

• Absorption: Vitamin D is fat-soluble, so it is recommended to take its preparations with a meal containing fat, which can improve its absorption.
• Time of day: Vitamin D can be taken at any time of the day, such as with breakfast or lunch. Some sources suggest avoiding supplementation in the evening, as it can theoretically affect the production of melatonin (the sleep hormone).
• Form: Various forms are available: capsules (often with oil), tablets, drops. There is no clear evidence that preparations in oil form are significantly better absorbed than tablets. The choice of form depends on the patient’s preferences.
• Medical consultation: It is always recommended to consult a doctor or pharmacist before starting supplementation, especially if you are using other medications, have chronic diseases (especially kidneys, liver, sarcoidosis, hypercalcemia) or plan to use doses higher than standard prophylactic doses.
• Risk of overdose: Although vitamin D toxicity is rare and usually the result of taking very high doses over long periods of time, it should be avoided. Symptoms of excess (hypervitaminosis D) can include nausea, vomiting, constipation, abdominal pain, loss of appetite, excessive thirst and urination, weakness, headaches, mood disturbances, and in severe cases lead to hypercalcemia (too high levels of calcium in the blood), which can damage the kidneys (kidney stones, kidney calcification), blood vessels (calcifications) and heart (arrhythmias).

More recent Polish guidelines (from 2023) also allow the use of calcifediol (metabolite 25(OH)D) as an alternative method of prevention or second-line treatment, especially in situations where the response to standard cholecalciferol is insufficient or when it is necessary to raise vitamin D levels in the body more quickly. Calcifediol works faster, but requires more caution and more frequent monitoring of 25(OH)D levels in the blood (as early as 6-8 days after starting use).

Due to the chronic nature of the problem of vitamin D deficiency in Poland, resulting from the limited possibilities of skin synthesis for most of the year, supplementation for many men is not a temporary solution, but requires a long-term, systematic approach – often throughout the year, especially in risk groups. This requires education and awareness of the need to take the right doses regularly and consistently.

Summary

Vitamin D plays an extremely important, multidirectional role in the male body, affecting the health of bones and muscles, the functioning of the immune system, hormonal balance (including potentially testosterone levels), fertility, mood and the prevention of many civilization diseases. Unfortunately, its deficiencies are a common phenomenon in the Polish population, which is mainly due to insufficient exposure to sunlight for most of the year, limited dietary supply and factors related to the modern lifestyle.

The consequences of a long-term deficiency can be serious and include an increased risk of osteoporosis and fractures, cardiovascular disease, metabolic disorders (insulin resistance, type 2 diabetes), autoimmune diseases, as well as potentially certain cancers, including prostate cancer. Symptoms of deficiency are often non-specific (fatigue, muscle and bone pain, reduced immunity, deterioration of mood), which makes early diagnosis difficult without laboratory tests.

That’s why it’s so important for men to be aware of the risk of vitamin D deficiency and potential symptoms. It is recommended to pay attention to the signals sent by the body, and if in doubt – to test the level of 25(OH)D in the blood. If a deficiency is identified or as part of prevention, it is crucial to implement appropriate measures. These include wise use of the sun in the summer, enriching the diet with products rich in vitamin D, and above all – rational and regular supplementation, tailored to individual needs and in accordance with current Polish guidelines.

Taking care of adequate vitamin D levels is not only a way to avoid the direct effects of vitamin D deficiency, but also an important investment in the long-term health, physical and mental fitness, and overall quality of life of every man. Given the broad spectrum of this vitamin and the prevalence of its deficiencies, effective preventive and therapeutic measures are important not only for the health of the individual, but also in the broader context of public health and socio-economic, contributing to reducing the burden of chronic diseases.