Close this search box.

Vitamin D guide. Vitamin D deficiency and sources of vitamin D


Vitamin D deficiency is a common health problem worldwide, affecting approximately 1 billion people. This vitamin plays an indispensable role, especially in maintaining healthy bone structure. It is essential for the human body; it promotes bone and dental health as well as muscle function by increasing the absorption of calcium and phosphorus. This deficiency can predispose to various health problems and therefore prevention and treatment of vitamin D deficiency is of great importance for public health .

The aim of this article is to familiarise readers with the symptoms and causes of vitamin D deficiency and how it can be addressed. In addition, foods containing vitamin D and the role of sunlight in the synthesis of this vitamin will be discussed in detail. In the article, while providing information under basic headings such as ‘What is Vitamin D and Why is it Important?’, ‘Benefits of Vitamin D’, ‘Causes of Vitamin D Deficiency’, ‘Symptoms of Vitamin D Deficiency’, ‘Treatment of Vitamin D Deficiency’, ‘Importance of Sunlight’, ‘Foods Containing Vitamin D’, answers will be given to curious questions such as ‘Which foods contain vitamin D?’, ‘How to eliminate vitamin D deficiency?’ and practical suggestions on ‘Vitamin D supplementation’ will be presented. We aim to provide readers with a comprehensive and informative perspective on vitamin D.

What is Vitamin D and Why is it Important?

Vitamin D is a fat-soluble vitamin that is vital for the body and helps to build and maintain strong bones, especially by ensuring that calcium levels are adequate. Here is some basic information about the importance of vitamin D and its role in the body:

  • Critical Role for Bone Health: Vitamin D forms the basis of bone and dental health by increasing the absorption of calcium and phosphorus. Without adequate vitamin D intake, bone diseases such as rickets in children and osteomalacia in adults can develop. These conditions are characterised by bone pain and muscle weakness.
  • Importance of Sunlight and Food Sources: The body naturally produces vitamin D when exposed to the UVB rays of sunlight. However, vitamin D can also be obtained from foods such as oily fish such as salmon, mackerel, sardines, fish liver oils, beef liver, cheese and egg yolks. These foods are known as rich sources of vitamin D.
  • Daily Requirement and Normal Levels: The daily vitamin D requirement of a healthy adult varies according to age and personal factors. 400 IU per day is recommended for infants under 1 year of age and 600 IU is recommended for individuals 1 year and older. In individuals over 70 years of age, this amount increases. Normal vitamin D levels are measured in ng/mL by blood test and should be between 20-50 ng/mL. Vitamin D deficiency is defined as levels falling below 12 ng/mL.

    Vitamin D deficiency can be caused by factors such as insufficient exposure to sunlight or dark skin pigmentation. Therefore, it is recommended to include vitamin D-rich foods in the diet and to take vitamin D supplements when necessary. Symptoms of vitamin D deficiency include bone weakness and pain, and adequate vitamin D intake is vital to prevent this condition. In the light of this information, it is of great importance to understand the role of vitamin D in the body and to get enough of this valuable vitamin to maintain a healthy life.

What are the Benefits of Vitamin D?

Vitamin D fulfils many important functions for body health and its deficiency can lead to various health problems. Here are the benefits of vitamin D:

  • Bone and Dental Health:
    • Vitamin D keeps bones and teeth healthy by regulating calcium and phosphorus levels.
    • This vitamin has a critical role in preventing bone diseases such as rickets in children, osteomalacia in adults and osteoporosis in the elderly.
  • Immune System and Fighting Diseases:
    • Vitamin D strengthens the immune system, protects the body against infections and supports the healing process of diseases.
    • It can help prevent various diseases such as heart disease, high blood pressure, diabetes, some types of cancer and multiple sclerosis (MS).
  • Functions of Internal Organs:
    • Vitamin D contributes to the maintenance of overall body health by supporting lung function and cardiovascular health.
    • By helping to regulate insulin levels, it can reduce the risk of diabetes and contribute to improved sleep patterns.

      Vitamin D deficiency can lead to serious health problems. This condition has been associated with osteoporosis, diabetes mellitus, hypertension, cardiovascular diseases, autoimmune diseases, sleep disorders, cancer and increased risk of death. Therefore, adequate vitamin D intake is vital for maintaining overall health and improving quality of life. Taking vitamin D supplements may be especially important for individuals who show signs of vitamin D deficiency. Knowing the answer to the question of which foods contain vitamin D and consuming these foods regularly will help maintain the vitamin D levels the body needs.

What are the Causes of Vitamin D Deficiency?

The causes of vitamin D deficiency are varied and many factors can contribute to this condition. Here are some of these factors:

  • Lack of Sunlight:
    • The UVB rays of sunlight are critical for synthesising vitamin D through the skin. However, these rays cannot penetrate through glass and sunscreens can block these rays from reaching the skin.
    • During the winter months, exposure to sunlight becomes more difficult and it is harder for individuals who spend a lot of time indoors to get enough vitamin D.
  • Physical Characteristics and Lifestyle:
    • Dark Skin: Melanin reduces the skin’s response to sunlight, which may limit vitamin D production in people with dark skin.
    • Obesity: Excess body fat can reduce the conversion of vitamin D into its active form.
    • Age: Aging reduces the capacity of the skin to synthesise vitamin D and the efficiency of the kidneys to convert vitamin D into its active form.
    • Infants and Breastfeeding: Breast milk may not provide enough vitamin D for infants, increasing the risk of deficiency in breastfed infants.
  • Health Conditions and Medication Use:
    • Medical Conditions: Various health conditions, such as liver disease, kidney disease, and cystic fibrosis, can affect the metabolism of vitamin D and lead to deficiency.
    • Medications: Some medications, such as anticonvulsants and corticosteroids, can affect the metabolism of vitamin D and cause deficiency.

      These factors can directly affect the vitamin D levels of individuals and increase the risk of deficiency. When symptoms of vitamin D deficiency occur, it is important to consider these risk factors and take appropriate measures. Issues such as which foods contain vitamin D and vitamin D supplementation play a vital role in preventing and managing deficiency.

Symptoms of Vitamin D Deficiency

Vitamin D deficiency is a health problem that occurs when the body does not get enough of this vital vitamin. Deficiency symptoms are usually obvious and can lead to various disorders. Here are the most common symptoms of vitamin D deficiency:

  • General fatigue and weakness: Lack of sufficient vitamin D in the body can cause a constant feeling of fatigue and low energy.
  • Bone and Muscle Pain: Vitamin D is critical for bone health and in case of deficiency, pain in the bones and weakness in the muscles may occur.
  • Mood Changes: Mood changes such as depression and irritability are among the psychological symptoms of vitamin D deficiency.
  • Frequent Infections: Because vitamin D helps keep the immune system strong, its deficiency can lead to frequent infections.

    Symptoms of vitamin D deficiency may include:
  1. Bone Pain Aches and pains felt in various parts of the body.
  2. Muscle Weakness: Muscle weakness or easy fatigue during daily activities.
  3. Fatigue and exhaustion: Tiredness and lack of energy more quickly than usual.
  4. Depression A general state of unhappiness, apathy and loss of motivation.
  5. Frequent Infections: More frequent infections such as colds and flu.
  6. Hair Loss Excessive hair loss and weakened hair strands.
  7. Headache and insomnia: Constant headaches and irregular sleep patterns.
  8. Tingling in Hands and Feet: Numbness and tingling felt in the nerve endings.

    These symptoms are possible indicators of vitamin D deficiency and may vary from person to person. If any of these symptoms persist for a long period of time, it is important to consult a health professional and have the necessary tests performed. It is also important in this process to find answers to the question of vitamin D supplementation and which foods contain vitamin D for the treatment of vitamin D deficiency.

Treatment of Vitamin D Deficiency

Healthy individuals can get about 100-150 IU vitamin D per day from a balanced diet, but a significant deficiency may still remain. The following steps should be followed for the treatment of vitamin D deficiency:

  1. Measurement of Vitamin D Level:
    • Vitamin D levels should be measured at least twice a year.
    • Diagnosis begins with a blood test to measure the level of 25-hydroxyvitamin D.
    • Treatment should be organised according to the doctor’s advice.
  2. Vitamin D Supplementation:
    • Vitamin D supplements are available in D2 (ergocalciferol) and D3 (cholecalciferol) forms, with D3 being more effective.
    • A health professional should be consulted before starting supplementation.
    • Daily intake varies depending on age and other factors; 600-800 IU is recommended for adults.
    • In special cases such as obesity, drug use or malabsorption syndromes, the dosage may be increased.
  3. The Role of Sunlight and Nutrition:
    • Treatment of vitamin D deficiency includes a balanced diet and adequate exposure to sunlight.
    • Foods rich in vitamin D should be consumed.
    • Exposure to sunlight should be done with caution, protective measures should be taken to avoid increasing the risk of skin cancer.

      During the treatment process, caution should be exercised when taking vitamin D supplements, as excessive vitamin D intake can cause hypocalcaemia and lead to nausea, vomiting, kidney stones and, in severe cases, kidney failure and heart rhythm disorders. Vitamin D supplementation should also be done under the supervision of a doctor for pregnant and breastfeeding women and individuals with certain medical conditions such as kidney disease. During the treatment process, an initial loading of 50,000 IU of vitamin D may be given once a week, followed by a maintenance dose of 1500-2000 IU daily. After starting treatment, serum 25(OH)D levels should be measured after 3-6 weeks and the dosage adjusted if necessary. The optimal daily vitamin D intake for adults is considered to be 1500-2000 IU and the treatment goal is to maintain serum 25(OH)D levels between 30-50 ng/ml. The safe daily limit of vitamin D intake is 4000 IU. An overdose of vitamin D supplements can lead to hypocalcaemia, so it is essential to consult a health care professional before starting supplementation.

Importance of Sunlight

Exposure to sunlight is vital for the production of vitamin D in our body. UVB rays in particular play a critical role in this process. However, the duration of exposure to sunlight, which is effective in vitamin D synthesis, varies depending on several factors:

  • Skin Type: Light-skinned people can produce vitamin D in a shorter time than dark-skinned people.
  • Geographical Location: People living near the equator can produce vitamin D faster because they are exposed to higher UVB rays.
  • Time of day and season: Vitamin D production is higher at noon and in summer when sunlight is highest.
  • Sunscreen Use: Sunscreens can block UVB rays from reaching the skin, which can reduce vitamin D production.

    Since overexposure to sunlight can lead to skin damage and skin cancer, it is important to balance the duration of sun exposure. Things to consider when sunbathing:
  • Daily exposure to sunlight for between 15-30 minutes can ensure sufficient vitamin D production for the body.
  • Exposure time should be adjusted according to skin type and the intensity of sunlight.
  • To avoid increasing the risk of skin cancer, sunscreen products should be used, especially in cases of prolonged sunbathing.

    Complications of vitamin D deficiency can lead to serious health problems such as osteomalacia, osteoporosis, rickets in children and increased risk of falls and fractures. Therefore, the following steps can be taken to increase vitamin D intake naturally:
  • Regular exposure to sunlight helps prevent vitamin D deficiency.
  • Consuming foods rich in vitamin D supports meeting the daily need.
  • Using vitamin D supplements offers an alternative solution for those who cannot get enough sunlight exposure or who cannot meet their needs through diet.

Which Foods Contain Vitamin D?

Vitamin D intake is important for a healthy life and can be obtained from various foods as well as sunlight. Here are some important food sources containing vitamin D and their vitamin D content:

  • Fatty Fish:
    • Salmon: Contains about 250 IU of vitamin D per 100 grams.
    • Mackerel: Approximately 200 IU of vitamin D per 100 grams.
    • Sardines: Provides 177 IU vitamin D per 100 grams.
    • Tuna: Rich in vitamin D and regular consumption is recommended.
    • Cod liver oil: Known for its high vitamin D content.
  • Other Animal Sources:
    • Beef liver: Contains about 50 IU of vitamin D per 100 grams.
    • Cheese: Swiss cheese in particular contains 12 IU of vitamin D per 100 grams.
    • Egg yolk: One egg yolk contains about 20 IU of vitamin D.
  • Plant Sources and Fortified Foods:
    • Mushrooms: Dried shiitake mushrooms exposed to UV light can provide 114 IU of vitamin D per 100 grams.
    • Fortified milk: Contains about 124 IU of vitamin D in a glass.
    • Fortified orange juice: One glass contains 100 IU of vitamin D.
    • Fortified cereals: May contain between 40-130 IU of vitamin D in a glass.

      When taking vitamin D supplements, consuming these foods with healthy fats provides better absorption of vitamin D by the body. Regular consumption of foods containing vitamin D plays a critical role in preventing deficiency, especially in areas with limited exposure to sunlight. Consumption of these foods should be planned as part of a balanced diet, taking into account the symptoms of vitamin D deficiency. As an answer to the question of what contains vitamin D, you can ensure adequate vitamin D intake by adding these foods to your diet and take full advantage of vitamin D benefits.

Vitamin D deficiency, which is vital for our health, plays a key role in preventing many health problems. Being aware of the symptoms examined in the article and how vitamin D can be provided by natural and supplementary means will directly affect the quality of life. In the light of the information and recommendations, maintaining vitamin D balance is of vital importance and requires a careful approach to our health status.

Underlining the importance of vitamin D not only for health, but also for overall quality of life, has created an awareness of how the available information can be applied in practice. Remember that vitamin D intake can be balanced both naturally and through tailored supplements; please consult your healthcare professional for more information. Measuring our vitamin D levels and taking appropriate supplements as needed is a critical step in supporting our overall health.

Most frequently asked questions about Vitamin D

Which Fruit is Richest in Vitamin D?

Vitamin D is present in almost all fruits, but oranges and apples are particularly important fruits that contain this vitamin. Although oranges are famous for vitamin C, they are also rich in vitamin D. Apple is another fruit that is recommended to be consumed in winter and contains vitamin D.

What Kind of Foods Should People with D Deficiency Consume?

Good food choices for people with vitamin D deficiency include oily fish (salmon, sardines, herring, swordfish, tuna, mackerel), beef liver and egg yolks. These foods are very rich in vitamin D.

How Can Vitamin Levels Be Increased Fastest?

The fastest way to raise vitamin D levels is through exposure to sunlight. The amount of vitamin D taken in through food is limited and the foods with the highest vitamin D content are oily fish (salmon, mackerel, sardines) and egg yolks.

What measures can be taken at home for vitamin D deficiency?

To combat vitamin D deficiency at home, it is useful to consume tuna, milk, eggs, cereals and mushrooms. Cheese, butter, yoghurt and kefir are also foods containing vitamin D. The vitamin D taken is activated in the liver and kidneys and shows its effect in the body.

Recent Posts
Scroll to Top