What vitamin is crucial for calcium absorption and bone development?

Vitamin D is crucial for calcium absorption and bone development because it promotes the efficient uptake of calcium in the intestines. It acts as a hormone that regulates calcium levels in the blood and plays a vital role in maintaining bone health. When the body has adequate vitamin D, calcium can be absorbed effectively, which is essential for forming and maintaining strong bones. Without sufficient vitamin D, calcium absorption can be impaired, leading to weakened bones and increasing the risk of conditions such as rickets in children and osteoporosis in adults. This underscores why vitamin D is often referred to as the "sunshine vitamin," as the body synthesizes it when exposed to sunlight, which is a key factor in ensuring adequate levels for bone health.