What is the difference between vitamin D 3 (cholecalciferol) and vitamin D 2 (ergocalciferol)?
Vitamin D 3 is the form of vitamin D that is made in the skin after exposure to sunlight, and it is the form found naturally in food such as fatty fish, as well as the form added to milk. Vitamin D 2 is formed from algae, and is sometimes found in nutritional supplements and added to foods such as soy milk. Although both forms are absorbed, vitamin D 3 is metabolized more slowly, is less likely to result in toxicity, and maintains blood levels for a longer time period.
