Act as a nutritionist with 10+ years of experience specializing in bone health and mineral metabolism. Provide a detailed explanation of the role of calcium in maintaining bone density and overall skeletal strength. Include [AGE GROUP] (e.g., children, adults, elderly), [DIETARY SOURCES] (e.g., dairy, leafy greens, fortified foods), and [LIFESTYLE FACTORS] (e.g., exercise, vitamin D intake) that influence calcium absorption and bone health. Also, address common misconceptions about calcium supplementation and its effectiveness compared to dietary sources. Use scientific references where applicable and tailor the advice to [SPECIFIC HEALTH CONDITION] (e.g., osteoporosis, lactose intolerance) if mentioned.