Overview#
Vitamin D deficiency is a condition where the body has insufficient levels of vitamin D, a hormone-like vitamin essential for bone health, immune function, and muscle strength. Paradoxically, despite abundant sunshine, 70-90 % of Indians are vitamin D deficient (25-OH vitamin D < 20 ng/mL). Contributing factors include darker skin pigmentation (more melanin reduces UV-mediated vitamin D synthesis), indoor lifestyles, air pollution blocking UV-B rays, and vegetarian diets low in natural vitamin D sources.
Causes & Risk Factors#
- Inadequate sun exposure – office workers, students, and women who cover most of their skin get insufficient UV-B radiation.
- Darker skin pigmentation – melanin acts as a natural sunscreen, reducing vitamin D synthesis by 50-90 % compared to fair skin.
- Air pollution – high particulate matter in Indian cities blocks UV-B rays, reducing skin synthesis.
- Vegetarian diet – few plant foods contain vitamin D; dairy in India is not routinely fortified.
- Obesity – vitamin D is sequestered in fat tissue, reducing its bioavailability.
Signs & Symptoms#
- Bone pain and muscle weakness
- Fatigue and generalised body aches
- Frequent infections and slow wound healing (immune dysfunction)
- Hair loss
- Depression and mood changes
- Bone softening (osteomalacia) in adults; rickets in children
- Lower back pain
- Muscle cramps and joint stiffness
Diagnosis#
- 25-Hydroxyvitamin D [25(OH)D] – the definitive test. Book Vitamin D Test
- Deficient: < 20 ng/mL
- Insufficient: 20-30 ng/mL
- Sufficient: 30-100 ng/mL
- Toxic: > 100 ng/mL
- Serum Calcium and Phosphorus – may be low in severe deficiency.
- Parathyroid Hormone (PTH) – elevated PTH with low vitamin D indicates secondary hyperparathyroidism.
- Alkaline Phosphatase (ALP) – may be elevated in osteomalacia.
- DEXA Scan – for bone density assessment if osteoporosis is suspected. Book Bone Health Panel
Treatment Options#
Supplementation (based on severity):
- Severe deficiency (< 10 ng/mL): Cholecalciferol (D3) 60,000 IU weekly for 8-12 weeks (sachets widely available in India), then monthly maintenance.
- Moderate deficiency (10-20 ng/mL): 60,000 IU weekly for 6-8 weeks, then monthly.
- Maintenance dose: 1,000-2,000 IU daily or 60,000 IU monthly after levels normalise.
- Always supplement with calcium (500-1,000 mg/day) alongside vitamin D for bone health.
Lifestyle measures:
- Get 15-20 minutes of midday sun exposure (10 AM-2 PM) on arms and legs without sunscreen, at least 3-4 times per week.
- Include vitamin D-rich foods: fatty fish (rawas/salmon, surmai/mackerel), egg yolks, fortified milk, and mushrooms exposed to sunlight.
- Vitamin D3 (cholecalciferol) is preferred over D2 (ergocalciferol) as it raises blood levels more effectively.
Prevention#
- Prioritise regular sun exposure – 15-20 minutes of midday sun on uncovered skin several times a week.
- Consider routine supplementation (1,000-2,000 IU/day) for high-risk groups: office workers, elderly, pregnant women, and people with dark skin.
- Include fortified foods where available – some Indian dairy brands now offer vitamin D-fortified milk.
- Get tested annually if you are in a high-risk group.
- Pregnant and breastfeeding women should take vitamin D supplements as advised by their obstetrician.
When to See a Doctor#
Consult a doctor if you have persistent bone pain, muscle weakness, or fatigue. Get tested if you have osteoporosis, frequent fractures, or a history of falls. Seek medical advice before taking high-dose supplements (> 4,000 IU/day) long-term, as toxicity can cause hypercalcemia (nausea, kidney stones, confusion).