Vitamin D is one of the fat-soluble vitamins and is rarely found in nature. Its precursors – plant-based ergo-calciferol (D2) and cholecalciferol (D3) from animal foods – are converted into the active form by sun exposure on the skin. These two forms are particularly important for the human body.
What are the functions of Vitamin D?
Vitamin D supports the absorption of calcium and phosphorus from the intestine and ensures their storage in bones and teeth. It also protects bones from mineral depletion, promotes skin cell development, and stimulates the immune system. Furthermore, Vitamin D acts as a prohormone and influences the formation of other hormones, such as insulin.
Vitamin D Deficiency: Causes & Symptoms
A Vitamin D deficiency is widespread, especially during winter months or in people who are exposed to little sunlight. Typical causes include insufficient sun exposure, a purely plant-based diet, absorption problems in the intestine, or the use of certain medications.
Symptoms of Vitamin D deficiency can include:
- Fatigue and listlessness
- Muscle weakness and bone pain
- Increased susceptibility to infections
- Brittle bones and osteoporosis
- In children: rickets (bone growth disorders)
Use of Vitamin D
Targeted intake of Vitamin D capsules or Vitamin D tablets is beneficial in many situations:
Rickets: Prevention in infancy.
Osteomalacia: Treatment of bone softening in adults.
Osteoporosis: Combination with calcium for prevention and therapy.
Absorption problems: e.g., in liver cirrhosis or malabsorption in the intestine.
Medication intake: Medications for heartburn or epilepsy can exacerbate a Vitamin D deficiency.
Those who cannot meet their needs through sun and diet should specifically buy Vitamin D and use high-quality Vitamin D capsules or Vitamin D tablets.
What foods contain Vitamin D?
Vitamin D is found primarily in fatty fish (e.g., cod liver oil), eggs, margarine, cheese, liver, beef, and mushrooms. However, intake through food alone is often insufficient, which is why additional supplementation with Vitamin D tablets can be beneficial.
Am I deficient in Vitamin D?
If even one of the following points applies to you, your Vitamin D supply might be insufficient. In such cases, it is advisable to take Vitamin D capsules and specifically buy Vitamin D:
- Are you rarely in the sun?
- Are you over 60 years old?
- Do you have an increased risk of osteoporosis?
- Do you follow a purely plant-based diet?
What should I consider when taking Vitamin D?
Vegetarians and vegans, as well as people who get little sunlight, have an increased risk of Vitamin D deficiency. In such cases, targeted Vitamin D supplementation is advisable.
However, Vitamin D should not be taken without limits: excessively high doses can cause side effects such as calcium deposits in tissues, kidney stones, or cardiac arrhythmias. Therefore, consult your doctor before taking more than the usual daily recommendation (DGE: 5 µg, 10 µg for older people).
