Most vitamin D is obtained from which source?

Most vitamin D is primarily obtained from sunlight. When the skin is exposed to ultraviolet B (UVB) rays from the sun, it synthesizes vitamin D in a process that involves converting cholesterol in the skin into this essential nutrient. While dietary sources of vitamin D, such as fortified foods and animal products, do contribute to overall intake, they do not provide the same volume of vitamin D as what can be synthesized through sun exposure.

Various factors can influence how much vitamin D a person receives from sunlight, including geographic location, season, time of day, and skin pigmentation. This makes sunlight a significant and natural source for most individuals, particularly for those who get adequate outdoor time during daylight hours.