Vitamin D deficiency is a widespread health concern that can affect various age groups and lead to multiple health issues, including heart disease, diabetes, and cancer. Vitamin D is essential for bone health as it helps in calcium absorption and maintaining phosphate balance. It also reduces inflammation, boosts immune function, and aids in cell growth. Signs of deficiency include fatigue, bone pain, and muscle weakness. Severe deficiency can lead to rickets in children and osteomalacia in adults. To prevent deficiency, it's important to get enough vitamin D through sunlight exposure, diet, and supplements if necessary. Foods rich in vitamin D include fatty fish, fortified milk, and eggs. The recommended daily intake varies by age and pregnancy status, with most adults needing 600 IU per day. People at higher risk for deficiency include those with darker skin, limited sun exposure, certain medical conditions, and restrictive diets. It's advisable to get your vitamin D levels tested if you are at risk and consult with a healthcare provider for appropriate supplementation.