Vitamin D – what does it help with? Properties, deficiency and excess

What is vitamin D? Types of vitamin D

Vitamin D, popularly called the "sunshine vitamin", plays a key role in numerous metabolic processes in the human body, especially in regulating the levels of calcium and phosphorus, which are essential for the health of bones and teeth. Its unique ability to be synthesized in the skin under the influence of UVB solar radiation distinguishes it from other vitamins that we must supply with food.

Types of vitamin D there are two and they include:

  • Vitamin D2 (ergocalciferol), which is produced by plants and fungi. It can be found in foods such as fortified breakfast cereals, some mushrooms, and supplements.
  • Vitamin D3 (cholecalciferol), synthesized by the skin of humans and animals after exposure to the sun and found in animal products such as fatty fish (salmon, mackerel, sardines), fish oil and liver.

Both types of vitamin D are converted in the liver and kidneys to the active form of the hormone, known as calcitriol, which is extremely important for many body functions, including the regulation of calcium and phosphorus absorption, as well as muscle function and the immune system. Regardless of the form, both vitamin D2 and D3 are crucial in preventing deficiencies that can lead to disorders such as rickets in children and osteoporosis in adults.

Although vitamin D is available in two forms, research suggests that vitamin D3 may be more effective in raising and maintaining adequate levels of vitamin D in the blood for longer periods of time. Therefore, it is recommended that people at risk of deficiency consider consulting a doctor who will help you choose the appropriate form of supplementation, depending on your diet, lifestyle and individual health needs.

Properties and effects of vitamin D on the body

Vitamin D, known for its key role in maintaining bone health, also has a profound impact on the body's overall immunity and healthy aging. As noted by Prof. Carsten Carlberg from the Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, its action goes beyond simple regulation of calcium and phosphorus levels in the body. Research conducted by Prof. Carlberg and his team, which can be found on the website of the Polish Academy of Sciences here, indicate that vitamin D influences the modulation of immune functions and can counteract various chronic diseases, including age-related ones.

The role of vitamin D in immunity

Vitamin D plays an important role in strengthening the body's immune response, influencing the function of white blood cells and reducing inflammation. White blood cells, including macrophages and T lymphocytes, have receptors for vitamin D, which allows it to directly influence their functioning. Therefore, its sufficient level is necessary for the optimal functioning of the immune system and can help prevent both infections and autoimmune reactions of the body.

Vitamin D and aging

In the context of aging, vitamin D may play a key role in delaying or minimizing the degenerative processes that are a natural part of aging. Prof. Carlberg points to the link between adequate vitamin D levels and maintaining cognitive function, skin health and minimizing the risk of developing cardiovascular diseases and some types of cancer. Additionally, research shows that high levels of vitamin D may support the preservation of telomere length, which is associated with longer cell lifespan.

Prevention and management of chronic diseases

Vitamin D is also being studied for its role in the prevention and management of chronic diseases such as type 2 diabetes, hypertension, and cardiovascular diseases. Its effect on the regulation of insulin and blood pressure suggests that adequate levels of this vitamin may be important in the prevention and treatment of these conditions.

Conclusions from the research of Prof. Carlberg and his team emphasize how multidimensional the role of vitamin D in the human body is. Further research may provide even more information about its potential to improve quality of life, especially in older people. Therefore, considering its importance for health, it is recommended to regularly monitor vitamin D levels, especially in regions with limited sun exposure, as well as in the elderly.

Vitamin D and aging – new research

Recent research indicates that vitamin D may help combat aging processes by strengthening immunocompetence, i.e. the ability to defend against diseases. This is especially important in the context of the decreasing number of immune cells in older people.

In the face of the natural and inevitable aging process, science is constantly looking for ways to delay it and maintain good health. One of the key areas of research is the role of vitamin D, which, although widely known for its impact on bone health, plays a much broader role in the body, influencing, among other things, immunity and the aging process.

Prof. Carsten Carlberg from the Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences in Olsztyn, recognized bioca chemist specializing in research on vitamin D, emphasizes that this vitamin may be the key to understanding the mechanisms that protect against many diseases and promote healthy aging. According to his latest research, published on February 23.02.2024, XNUMX, the so-called immunocompetence, i.e. the body's general immunity, can be strengthened by an adequate level of vitamin D, which is important not only in the context of fighting pathogens, but also in the context of non-communicable diseases and the aging process itself.

It is important to emphasize that the research presented concerns the overall effect of vitamin D on the body and should not be interpreted as evidence of the therapeutic effects of vitamin D supplements. Dietary supplements are intended only to supplement the diet and cannot be promoted as therapeutic agents. Detailed information about the research can be found in the publication available at the link:

Prof. In his research, Carlberg divided the population into three groups according to the level of the body's reaction to vitamin D: high, medium and low responders. He observed that people in the highly responsive group have the ability to make the most of the effects of vitamin D, which may suggest a lower need for supplementation in this group of people.

Observations regarding the influence of vitamin D on the aging process are also very interesting. Prof. Carlberg noted that as overall immunity declines in the aging process, the relative number of immune cells also declines. However, it is worth noting that there are individual differences in immunity among older people, which may influence the rate of aging and the incidence of disease.

Research shows that an adequate level of vitamin D, adapted to the individual needs of the body, may not only support the maintenance of bone and muscle health, but also contribute to stabilizing immunity and protection against various diseases, as well as helping to maintain a slower rate of aging.

To sum up, although dietary supplements with vitamin D can provide valuable support in maintaining health and immunity, it is important to remember about their proper use and the role they play in our everyday lives. It is recommended to consult a doctor or dietitian before starting supplementation to adapt it to individual needs and avoid overuse.

What is the normal level of vitamin D? Norms

The recommended daily allowance (RDA) of vitamin D can vary significantly depending on age, gender, health status, as well as the latitude and health policies of a given country. It is generally accepted that the norm for adults is about 600-800 IU (international units) per day, but for seniors, the recommendations may increase to 1000 IU to prevent osteoporosis and other age-related health problems.

Standards in the United States

In the US, according to the National Academy of Sciences, Engineering and Medicine, the recommended daily intake of vitamin D is 600 IU for people aged 1 to 70 years and 800 IU for people over 70 years of age. For infants (0-12 months), the recommended intake is 400 IU per day.

Standards in Europe

The European Food Safety Authority (EFSA) recommends a daily dose of 800 IU for adults, including older people, and pregnant and breastfeeding women. For children and adolescents, the recommended dose is 600 IU per day.

Standards in Canada

In Canada, as in the USA, the recommended dose is 600 IU per day for adults up to 70 years of age and 800 IU for older people. For small children, the recommended dose is 400 IU.

Standards in Australia and New Zealand

In Australia and New Zealand, standards are similar to those in Europe and North America, with recommendations of 600 IU for adults and 800 IU for people aged 70 and over. Children and adolescents should consume 600 IU per day.

Standards in Asia

Vitamin D intake recommendations in Asian countries may vary due to lower sun exposure in some regions. For example, in India, 400 IU is recommended for adults, but some studies suggest raising the figure to 1000 IU, especially for people with limited sun exposure.

The importance of monitoring vitamin D levels

Regardless of regional recommendations, it is important to regularly monitor your body's vitamin D levels, especially for people who spend a lot of time indoors or live in regions with low sunlight. Vitamin D deficiency can lead to many health problems, including weakened bones, increased risk of fractures, and problems with the functioning of the immune system.

Vitamin D deficiency – what are the symptoms?

Vitamin D deficiency in the body can manifest itself in various ways, affecting overall well-being and physical and mental health. The symptoms of vitamin D deficiency are often subtle or ambiguous, which can make them difficult to diagnose quickly. The most common symptoms are:

Fatigue and weakness

Chronic fatigue, lack of energy and general weakness can be some of the first signs of vitamin D deficiency. People with this problem often complain of feeling exhausted, even after getting enough sleep.

Bone and muscle pain

Vitamin D deficiency can cause pain and discomfort in the bones and muscles, which is often confused with symptoms of fatigue or aging. This condition is characterized by a feeling of pain or constant tension in the lower back, hip bones and legs.

Weaker immunity

People suffering from vitamin D deficiency may experience more frequent infections, such as colds or flu. Vitamin D plays a key role in the functioning of the immune system, and its lack may weaken the body's ability to fight pathogens.

Mood problems

Vitamin D deficiency can also affect sanity, leading to mood changes such as sadness or depression. Research suggests that adequate levels of vitamin D are necessary for the production of serotonin, a neurotransmitter that affects mood, appetite and sleep.

Increased risk of developing chronic diseases

Long-term vitamin D deficiency can contribute to the development of a number of chronic diseases, such as osteoporosis (characterized by weakened bones that become more susceptible to fractures), as well as osteomalacia in adults, which manifests itself as softening of the bones. Associations have also been observed between vitamin D deficiency and an increased risk of certain types of cancer, type 2 diabetes, and cardiovascular disease.

Increased risk of autoimmune diseases

Vitamin D deficiency is associated with a greater risk of developing certain autoimmune diseases, such as multiple sclerosis and rheumatoid arthritis.

Problems with regeneration and healing

It has been observed that vitamin D deficiency may slow down the healing process of wounds after surgery or other injuries, which further hinders regenerative processes in the body.

What is vitamin D in? The best sources

Vitamin D, also known as the "sunshine vitamin", is extremely important for many body functions, including bone, muscle and immune system health. Although natural synthesis in the skin under exposure to sunlight is the main source of vitamin D for most people, there are also numerous dietary sources that can help maintain adequate levels of the vitamin during periods of less sunlight or for people who avoid sun exposure for various reasons.

Animal sources of vitamin D

  • Oily fish: These are some of the best sources of vitamin D3. Salmon, mackerel, sardines and tuna contain high amounts of vitamin D, which is easily absorbed by the human body.
  • Liver: Cod liver in particular is a valuable source of vitamin D, also offering other valuable ingredients such as vitamin A and acids omega-3.
  • Jaja: Egg yolks, in particular, are a good source of vitamin D, providing a convenient option for people who don't prefer fish.

Plant sources and enriched with vitamin D

  • Enriched products: Milk, yogurt, margarine and breakfast cereals are often fortified with vitamin D, making them easily available sources of the vitamin, especially for people who do not eat enough fatty fish or liver.
  • Mushrooms: Some types of mushrooms, such as oyster mushrooms and champignons, can synthesize vitamin D2 when exposed to UV light, constituting one of the few plant sources of this vitamin.

Cutaneous synthesis of vitamin D

  • Sun exposure: Regular, moderate exposure to sunlight without using UV filters is the most natural way to increase vitamin D levels. Exposure to the face, hands and arms for about 10-15 minutes a few times a week is usually enough for most people to maintain healthy levels vitamin D, although these recommendations may vary depending on latitude, complexion and season.

Important notes

It is worth noting that the intake of vitamin D from food or supplements should be properly balanced. Excessive supplementation can lead to hypervitaminosis D, which can be harmful. Therefore, it is always recommended to consult a doctor or dietitian to determine individual needs and a safe level of supplementation.

Vitamin D from the sun and its synthesis in the skin: Mechanism biochemic

Vitamin D synthesis in human skin is a complex process biochemic, which occurs under the influence of UVB radiation from natural sunlight. This endogenous vitamin D production mechanism is crucial for many physiological functions in the body, including calcium metabolism and phosphate homeostasis, which have a direct impact on maintaining bone health and mineral balance.

The process of vitamin D synthesis

Vitamin D synthesis begins when 7-dehydrocholesterol (7-DHC), a precursor of vitamin D3, present in significant amounts in the cell membranes of epidermal keratinocytes, is broken down by UVB radiation. The absorption of UVB photons by 7-DHC leads to its photolysis and transformation into previtamin D3. This unstable compound quickly undergoes thermal isomerization, transforming into vitamin D3, also known as cholecalciferol.

The role of temperature and other factors

It is worth noting that the rate of isomerization of previtamin D3 to vitamin D3 depends on skin temperature, which explains why in winter, when the skin is usually colder, there may be reduced production of vitamin D even with sufficient exposure to sunlight. Moreover, variable penetration of UVB rays depending on latitude, season, day and weather conditions, as well as individual differences in skin pigmentation, affect the efficiency of vitamin D synthesis.

Vitamin D3 metabolism

Once produced, vitamin D3 is transported from the epidermis into the blood, where it binds to vitamin D-binding protein (DBP) and is transported to the liver. In the liver, vitamin D3 is hydroxylated by the enzyme 25-hydroxylase, resulting in the formation of 25-hydroxyvitamin D (25(OH)D), the main form of circulating vitamin D. Further hydroxylation in the kidneys by 1-α-hydroxylase leads to the formation of the active hormonal form , 1,25-dihydroxyvitamin D (1,25(OH)₂D), also known as calcitriol, which is crucial for regulating calcium and phosphorus levels in the body.

Sun exposure recommendations

Although the natural production of vitamin D is extremely important, moderate sun exposure is recommended to minimize the risk of skin damage and the development of skin cancer. The optimal exposure time may vary depending on skin type, geographical location and current weather conditions, but it is generally accepted that short, regular periods (about 10-15 minutes several times a week) without the use of sunscreen may be sufficient for most of the population.

When and how to supplement vitamin D?

In Europe

In Europe, where weather conditions often limit sun exposure, especially during the winter months, vitamin D supplementation is widely recommended. European guidelines suggest supplementation especially for the elderly, children, pregnant women and people with darker skin who are more vulnerable to deficiencies. Consultation consultation with a doctor is crucial to determine the appropriate dose, which often ranges from 800 to 2000 IU per day, depending on individual needs, level of daily activity and diet.

Outside Europe

On other continents, such as North America, Asia or Australia, recommendations may vary depending on the climate and lifestyle of the population. In regions with high sun exposure, such as Australia, caution in supplementation is recommended due to greater sun exposure. In such cases, it is recommended to regularly check the level of vitamin D in the body to avoid supplementation without a proven need. In Asian countries, where traditional diets may not provide sufficient amounts of vitamin D and the culture of wearing full-body clothing is more common, greater awareness and the possible need for supplementation are recommended.

Excess vitamin D – can you overdose on vitamin D?

In Europe

In Europe, where supplementation is widely used, there is a risk of excess vitamin D, which can lead to hypercalcemia. Hypercalcemia may result in kidney damage, the formation of kidney stones, and negatively affect the heart and circulatory system. European health agencies recommend regular monitoring of calcium levels in people supplementing vitamin D, especially when doses exceed 4000 IU per day.

Outside Europe

In other regions of the world where supplementation practices may be less regulated, education about the potential risks of excessive vitamin D intake is crucial. In the United States, where supplements are readily available, the need to consult with a health care provider before starting supplementation is emphasized to avoid the risk of hypercalcemia. In countries where access to health care is limited, it is important to raise awareness of the possible risks associated with uncontrolled consumption of supplements.

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