Vitamin D, specifically 25-hydroxyvitamin D (25-OH vitamin D), is vital for bone health, aiding in calcium and phosphorus absorption, and plays a role in reducing inflammation, cell growth modulation, and supporting immune and neuromuscular functions. It is essential for preventing rickets in children, osteomalacia in adults, and linked to reducing the risk of osteoporosis, cardiovascular diseases, certain cancers, autoimmune conditions, and depression. Vitamin D levels are influenced by dietary factors, sun exposure, and individual characteristics like age and skin pigmentation.
Deficiency in vitamin D can cause weak bones in children (rickets) and adults (osteomalacia), and contribute to osteoporosis. Low levels are also associated with increased risks of cardiovascular diseases, certain cancers, and impaired immune function. Factors such as limited sun exposure, dark skin, obesity, and conditions affecting fat absorption like celiac or Crohn's disease can reduce vitamin D levels. Additionally, magnesium deficiency can impair vitamin D activation, and liver or kidney diseases can affect its conversion to active forms.
Conversely, vitamin D toxicity, though rare, can result from excessive supplementation, leading to hypercalcemia with symptoms like nausea and kidney complications. Balanced vitamin D levels are typically achieved through diet, sunlight, and possibly supplementation. Obesity can sequester vitamin D in fat tissue, reducing its availability, while aging and darker skin reduce skin-based vitamin D production. Regular monitoring is advised for those at risk of deficiency or on high-dose supplements.
To maintain healthy Vitamin D levels:
Ensure regular, safe sun exposure. Aim for 10-30 minutes of midday sunlight several times per week, depending on your skin type and location.
Consume vitamin D-rich foods such as fatty fish (salmon, mackerel, sardines), egg yolks, and fortified dairy products or plant-based alternatives.
Consider vitamin D supplementation, especially if you have limited sun exposure, darker skin, or live in northern latitudes. Consult with a healthcare provider for appropriate dosage.
Maintain a healthy weight, as obesity can affect vitamin D absorption and utilization.
Ensure adequate intake of magnesium, which is necessary for vitamin D metabolism. Include magnesium-rich foods like nuts, seeds, and leafy greens in your diet.
Vitamin D (25-OH) can be measured in: ng/100mL, ng/dL, ng/L, ng/mL, ng%, nmol/L, µg/L
Reference ranges represent typical values for healthy individuals. Your healthcare provider must interpret your specific results.
| Age Range | Gender | Unit | Optimal | Normal | Source |
|---|---|---|---|---|---|
| All ages | All genders | ng/mL | - | 25 - 80 | Pagana, 2019 |
Vitamin D has anti-inflammatory properties and plays a role in modulating the immune system. Low levels of vitamin D are associated with increased susceptibility to infection, chronic inflammation, and autoimmunity. Adequate vitamin D levels can help reduce inflammation and support immune health.[Cannell, 2015][Calton, 2015]
Explore 6 additional health topics related to this biomarker in the Health3 app.
Vitamin D, as calcitriol (1,25(OH)2D), increases intestinal phosphate absorption and also facilitates its renal reabsorption, leading to elevated serum phosphate levels[Akimbekov, 2022][Shaker, 2000].
Explore 3 additional biomarker interactions related to this biomarker in the Health3 app.
Save this biomarker reference for your medical appointments
Was this information helpful?
Monitor your biomarkers, visualize trends, and share insights with your care team.