Most vitamin D sold to consumers is vitamin D3, and there are two primary forms of vitamin D available for use in dietary supplements: cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2).

A vitamin D deficiency at that stage of life causes the thymus to age more quickly, the researchers discovered. The study is published in the journal Science Advances .

A new study reinforces the importance of vitamin D to health, especially as the onset of winter diminishes sunlight, the most effective way humans absorb the vitamin. The study, published in the ...