VITAMIN D: the importance of the “sunshine” vitamin

Vitamin D, also known as the antirachitic or sunshine vitamin, is fat-soluble. It has an important influence on various metabolic processes in the body, the most prominent of which is its effect on calcium metabolism. It works by promoting calcium and phosphorus utilisation from the digestive system, which is essential for the normal growth and mineralisation of bones and teeth.

Source of vitamin D

For the human body, there are two sources of vitamin D: it is partly produced in the skin under the influence of sunlight, i.e. ultraviolet light (UVB), and it is also introduced via food. Significant amounts of vitamin D are found in cod liver oil and coldwater fish, such as salmon and herring. The most well-known source of vitamin D are various types of fish oil, especially cod and herring oil. Certain amounts can also be found in red meat, liver and egg yolk.

Vitamin D is only present in animal source foods. However, most milk and dairy products contain low amounts of vitamin D, so in many countries these foods are enriched with vitamin D.

Maintaining the recommended level of vitamin D

According to some studies, almost half of the population in the temperate zone suffers from vitamin D deficiency, which is most pronounced in the winter months.

Factors affecting daily sunlight exposure in the warmer part of the year can significantly affect vitamin D level in the body. People with reduced sun exposure should include a quality source of vitamin D in their diet to ensure the recommended level.

Risk factors for the development of vitamin D deficiency

  • Lack of fish or enriched dairy products in the diet
  • Old age
  • Obesity
  • Dark skin colour
  • Application of sunscreen every time when going outdoors
  • Staying indoors for a prolonged period of time
  • Living at high latitudes, i.e. greater distance from the equator

Symptoms and consequences of vitamin D deficiency

Rickets (rachitis) and osteomalacia are classic conditions caused by vitamin D deficiency, but lately the importance of this vitamin for other organ systems and physiological processes has been increasingly observed.

Many people fail to notice that they are suffering from vitamin D deficiency because the symptoms can be very mild and difficult to recognise, although they can have a significant impact on daily functioning.

Some manifestations of vitamin D deficiency

  • Frequent infections (respiratory, digestive, skin etc.), as one of the most important roles of vitamin D is to maintain a strong immune response
  • Atopic dermatitis (eczema)
  • Fatigue and exhaustion that cannot be linked to another cause
  • Musculoskeletal pain
  • Listlessness
  • Slow wound healing
  • Bone mass loss
  • Specific form of hair loss in sharply circumscribed round or oval patches (spot baldness or alopecia areata)

It can be concluded that vitamin D is extremely important for the proper functioning of a number of organ systems. During the warmer part of the year, it is estimated that approximately 15 minutes of partial sun exposure (face, hands, feet) at least twice weekly is enough to synthesise sufficient amounts of this vitamin.

When practicing social distancing to reduce the possibility of coronavirus spreading, one should consider how to plan outdoor activities carefully so as to ensure that vitamin D can be synthesised in adequate amounts. Moreover, it is also possible to supplement vitamin D by using food supplements.

Marti Farm can assist you in the placing of food supplements on the market through obtaining a decision on the application of food supplements to the monitoring program. You can read more about the interactions between food supplements and medicinal products at the following link: Interactions between food supplements and medicinal products.

Spending time on a balcony or at a sunny window, in the absence of other options, could be a solution to this problem in the current situation.

Emina Gržanić,  DVM / Medical Affairs Manager

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Marti Farm Ltd. Trade and Services
Marti Farm Ltd.
Lašćinska cesta 40, HR-10000 Zagreb
Planinska ulica 13/2, HR-10000 Zagreb
a limited liability company
Commercial Court of Zagreb


Share capital
Authorized representative

HRK 20,000.00 (paid in its entirety)
Martina Diminić Smetiško, director of the
company (Representing the company
individually and independently, Responsible
person for data protection)


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HR3623600001102197724 (Zagrebačka banka)
HR4324020061100628669 (Erste banka)


Full company name: Marti Farm Ltd. Trade and Services
Short company name: Marti Farm Ltd.
Headquarters: Lašćinska cesta 40, HR-10000 Zagreb
Office: Planinska ulica 13/2, HR-10000 Zagreb
Legal form: a limited liability company
Court register: Commercial Court of Zagreb
Registration number: 080751121

OIB: 29969122438
Share capital: HRK 20,000.00 (paid in its entirety)
Authorized representative: Martina Diminić Smetiško, director of the company (Representing the company individually and independently, Responsible person for data protection)

Bank account: HR3623600001102197724 (Zagrebačka banka), HR4324020061100628669 (Erste banka)

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