Vitamin D

Vitamin D (also referred to as calciferol) is a fat-soluble vitamin that is naturally present in a few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet (UV) rays from sunlight strike the skin and trigger vitamin D synthesis.

Symptoms of a vitamin D deficiency include fatigue, bone pain, muscle weakness or aches, mood changes like depression, and getting sick more frequently. More severe deficiency can lead to osteoporosis, slow wound healing, and, in children, a condition called rickets, which causes soft, deformed bones.