What is the recommended daily intake of vitamin D?

The recommended daily intake of vitamin D for most adults is 600 IU (International Units) per day, which is essential for maintaining healthy bones, as it aids in calcium absorption. This recommendation takes into account various factors, including age and exposure to sunlight, which can naturally increase vitamin D levels in the body. Different life stages, such as infancy, childhood, and older adulthood, may have different needs, but the general guideline for adults is rooted in maintaining adequate blood levels for optimal health.

While the other options present different values for daily intake, 600 IU is aligned with guidelines set by health organizations, thus reinforcing its position as the appropriate recommendation for adults. It's crucial for individuals to be aware of their own dietary needs and consider factors like geographic location, diet, skin exposure to sunlight, and existing health conditions that affect vitamin D absorption and synthesis.