What is the function of Vitamin D3 (Cholecalciferol)?

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From the Guidelines

Vitamin D3 (Cholecalciferol) plays a crucial role in maintaining bone health by controlling calcium absorption in the small intestines and interacting with parathyroid hormone to help maintain calcium homeostasis between the blood and bones.

Key Functions of Vitamin D3

  • Calcium absorption: Vitamin D3 helps bones absorb calcium, which is essential for bone growth and maintaining bone density 1.
  • Muscle strength and balance: Stimulation of skeletal muscle receptors by vitamin D promotes protein synthesis and has a beneficial effect on muscle strength and balance 1.
  • Bone growth and density: Vitamin D3 is essential for bone growth and maintaining bone density, and insufficient amounts can lead to impaired dietary calcium absorption and weakened bones 1.

Recommended Intake and Supplementation

  • Daily dietary intake: The recommended daily intake of vitamin D is 600 IU in adults aged 18 to 70 years and 800 IU in adults older than 70 years 1.
  • Supplementation: Vitamin D3 (cholecalciferol) or vitamin D2 (ergocalciferol) can be used to treat vitamin D deficiency, and the choice of supplementation depends on the severity of the disorder and individual patient factors 1.

Special Considerations

  • Chronic kidney disease: Patients with chronic kidney disease (CKD) may require different supplementation regimens, and the role of 25(OH)D deficiency and its correction in patients on maintenance dialysis therapy is controversial 1.
  • Pediatric patients: Children and youth with vitamin D deficiency or insufficiency may require supplementation, and the recommended dosing regimen depends on the severity of the disorder and individual patient factors 1.

From the Research

Function of Vitamin D3

The primary function of Vitamin D3 (Cholecalciferol) is to maintain mineral homeostasis in the body, regulating calcium and phosphate levels through its effects on the intestine, kidney, parathyroid gland, and bone 2. This is achieved through the hormonal form of vitamin D, calcitriol, which is synthesized from vitamin D3 in the liver and kidneys.

Biological Role

The major biological function of vitamin D is to maintain serum calcium and phosphorus concentrations within the normal range, essential for cellular functions and skeleton mineralization 3. Vitamin D3 is also involved in the regulation of various cellular processes, including cell growth, differentiation, and immune function.

Health Effects

Vitamin D deficiency can lead to several health issues, including:

  • Bone diseases such as rickets, osteomalacia, and osteoporosis 2, 3, 4
  • Autoimmune diseases, cancer, and cardiovascular diseases 4, 5
  • Metabolic bone diseases, including osteoporosis and osteomalacia 6

Vitamin D Status Evaluation

The most common method to evaluate vitamin D status is by measuring serum levels of 25-hydroxyvitamin D (25(OH)D), with optimal values ranging between 75-125 nmol/L 6. Vitamin D deficiency is widespread, and ensuring optimal levels is a challenge for healthcare and government administration.

Key Points

  • Vitamin D3 is essential for maintaining mineral homeostasis and bone health
  • Vitamin D deficiency can lead to various health issues, including bone diseases and autoimmune disorders
  • Evaluating vitamin D status is crucial, and optimal levels can be achieved through sun exposure, diet, or supplementation
  • Ensuring optimal vitamin D levels is a challenge for healthcare and government administration 2, 3, 4, 5, 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Health outcomes of vitamin D. Part I. characteristics and classic role.

Roczniki Panstwowego Zakladu Higieny, 2014

Research

Vitamin D and bone health.

The Journal of nutrition, 1996

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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