Vitamin D Deficiency

Overview

Vitamin D helps the body absorb calcium and supports bone, muscle, and immune health. Levels are made mainly through skin exposure to sunlight, with smaller amounts from food, so deficiency is common in people who get little sun.

Symptoms

Many people have no symptoms. When present, they can include bone pain, muscle weakness or aches, fatigue, and — in severe, prolonged deficiency — bone softening (osteomalacia in adults, rickets in children).

Risk Factors

Limited sun exposure, darker skin (which produces vitamin D less efficiently from sunlight), older age, obesity, certain medications, malabsorption conditions, and living at higher latitudes or spending most time indoors all raise risk.

Common Blood Tests

Serum 25-hydroxyvitamin D (25(OH)D) is the standard test used to assess vitamin D status.

Lifestyle Information

Sensible sun exposure, vitamin D-rich foods (oily fish, egg yolks, fortified foods), and supplementation — particularly in autumn and winter months in temperate climates — are the main ways to maintain adequate levels.

When to seek medical advice

Speak to a doctor if you have persistent bone or muscle pain, or fall into a higher-risk group and haven't had levels checked, especially before starting high-dose supplements.

Sources