Vitamin D: What Is It, What Are Its Deficiencies, Symptoms, and Treatments?

Vitamin D deficiency is a significantly common condition in our country. To prevent issues related to vitamin D deficiency, society needs to be aware of its importance. Eating a healthy diet and getting enough sunlight are crucial in preventing vitamin D deficiency.

What Is Vitamin D?

Vitamin D is one of the fat-soluble vitamins. It can be obtained from food sources as well as produced in the body.

Vitamin D in the body affects many areas, including:

• Maintaining bone and dental health
• Cell division and differentiation
• Glucose metabolism
• Regulating immune system functions

Although vitamin D is a vitamin, it acts like a hormone. There are vitamin D receptors in many cells throughout the body, and vitamin D binds to these receptors to perform its functions within the cells.

Numerous studies are being conducted regarding vitamin D. These studies have shown that vitamin D can provide many benefits in various areas within the body. For example:

• High doses of vitamin D can help prevent osteoporosis, thereby reducing the risk of falls and fractures, especially in the elderly.
• Vitamin D contributes to increased physical strength in both lower and upper extremities (limbs).
• A study has shown that taking 1,100 IU of vitamin D daily may prevent cancer development.
• Vitamin D may help alleviate clinical symptoms of depression.
• One study indicated that vitamin D intake in infants reduces the risk of type 1 diabetes.

Vitamin D is synthesized from a precursor molecule called cholesterol in the body. Sunlight is needed for the production of this vitamin. Skin cells exposed to sunlight produce vitamin D. For this produced molecule to convert to its more active form, it must undergo several stages in the kidneys and liver. After these stages, the active form of vitamin D can begin to exhibit its effects in the body.

What Are the Symptoms of Vitamin D Deficiency?

Vitamin D deficiency causes a disease called rickets in children.

The most common symptoms of vitamin D deficiency are:

• Fatigue
• Bone pain
• Muscle weakness, muscle pain, or cramps
• Mood disorders such as depression

What Causes Vitamin D Deficiency?

The insufficiency of vitamin D that the body needs can lead to deficiency. The causes of deficiency can be categorized into three main groups:

1. Not getting enough vitamin D through diet
2. Disorders in the absorption and metabolism of vitamin D
3. Not getting enough sun exposure

Considering the fundamental conditions that lead to vitamin D deficiency, it is evident that certain groups are at risk of deficiency. These groups include:

• Elderly Individuals: With aging, the capacity to produce vitamin D decreases. Additionally, these individuals go outside less and receive less sunlight, increasing their risk of deficiency. Vitamin D deficiency in elderly individuals can adversely affect bone health, leading to issues such as hip fractures.
• Individuals Who Do Not Get Enough Sun Exposure: Those who prefer not to go outside frequently or cannot go out for specific reasons are at higher risk of vitamin D deficiency. Clothing that prevents skin cells from receiving adequate sunlight also poses a risk for deficiency.
• Individuals with Dark Skin: The pigment that gives skin its color is called melanin. Dark-skinned individuals have a higher amount of melanin in their skin cells. As the melanin content in cells increases, their capacity to produce vitamin D decreases. Therefore, dark-skinned individuals are more likely to experience deficiency.
• Individuals with Intestinal Diseases: Conditions affecting digestive functions, such as ulcerative colitis, Crohn's disease, cystic fibrosis, and celiac disease, can lead to issues with vitamin D absorption.
• Breastfed Infants: Breast milk does not contain sufficient vitamin D to meet an infant's needs. Therefore, it may be beneficial for infants to receive vitamin D supplementation under the guidance and recommendation of their pediatrician, as well as be exposed to sunlight in appropriate conditions to prevent deficiency.
• Obese Individuals: In people with obesity, the body’s fat tissue binds vitamin D, preventing it from entering the bloodstream. Low levels of vitamin D in the blood lead to deficiency symptoms.
• Individuals Taking Medications Affecting Vitamin D Metabolism: Certain medications such as cholesterol drugs, antiepileptics, agents used in AIDS treatment, antifungal drugs, and glucocorticoids can disrupt vitamin D metabolism. Therefore, individuals using these medications may experience vitamin D deficiency.

Pregnant or breastfeeding women should be cautious regarding deficiency as their vitamin D needs increase.

How is Vitamin D Deficiency Diagnosed?

To diagnose vitamin D deficiency, a blood test is performed. In the laboratory, the serum hydroxy-25 vitamin D level in the blood is measured. A measured value below 12 ng/ml is considered vitamin D deficiency. Healthy individuals should have a vitamin D level above 20 ng/ml.

What Symptoms are Associated with Vitamin D Deficiency?

Vitamin D deficiency can cause various disorders and problems in the body. Conditions that may arise from vitamin D deficiency include:

Rickets:

Rickets is a disorder seen in children. In this condition, there is a problem with the mineralization of the cartilage tissue that allows for bone growth, meaning it does not harden into bone properly. Symptoms of rickets that may be seen in children include:

• Pain and tenderness in the arms, legs, spine, and pelvis
• Growth stunting, short stature
• Muscle cramps
• Dental deformities such as holes in the enamel, delayed teething, abscesses
• Bone deformities such as curved spine, protruding breastbone, and bowed legs (O-legs)

Osteomalacia

Osteomalacia is a condition characterized by mineralization disorders in the bone, similar to rickets. This adult disease is often accompanied by widespread pain in the body, primarily in the hip region.

Frequent Infections

Vitamin D plays a regulatory role in immune system functions. In vitamin D deficiency, there may be an increase in the severity of viral infections. Additionally, the deficiency can lead to recurrent infections.

Hair Loss

As with other vitamin and mineral deficiencies, hair loss can also occur with vitamin D deficiency.

How is Vitamin D Deficiency Treated?

If vitamin D deficiency is not severe, vitamin supplements and increasing dietary intake of vitamin D may be sufficient for treatment. Unless otherwise specified by your healthcare provider, foods rich in vitamin D such as liver, eggs, milk, and dairy products can be consumed.

The daily required amount of vitamin D varies by age. The recommended daily intake of vitamin D is:

• 400 IU for infants aged 0-1
• 600 IU for children and adults aged 1-70
• 800 IU for individuals over 70 years old and breastfeeding women

IU stands for "International Unit." For better understanding, for example, consuming one egg provides 44 IU of vitamin D.

When a diagnosis of vitamin D deficiency is made in children, medical treatment should be initiated. As children are in a growth period, they may be more adversely affected by the deficiency. Treatment usually involves vitamin D injections. The number of injections a child will receive and how many drops should be taken daily from the injection is determined by the doctor.

The Ministry of Health in our country conducts free vitamin D supplementation programs to prevent vitamin D deficiency in infants and pregnant women.

Vitamin D deficiency can lead to serious problems. Regular monitoring of vitamin D levels in both children and adults can help in the early detection of this condition.