Vitamin D - Benefits and Sources

Vitamin D is a fat-soluble vitamin that plays a crucial role in calcium absorption, bone health, and immune function.

Vitamin D FAQ

Why is vitamin D called vitamin D?

He called it vitamin D because he thought it was the fourth vitamin to be named. It was not initially realized that vitamin D can be synthesized by humans (in the skin) through exposure to UV light, and therefore is technically not a vitamin, but rather can be considered to be a hormone.

Is vitamin D a nutrient?

Vitamin D is both a nutrient we eat and a hormone our bodies make. It is a fat-soluble vitamin that has long been known to help the body absorb and retain calcium and phosphorus; both are critical for building bone. Also, laboratory studies show that vitamin D can reduce cancer cell growth, help control infections and reduce inflammation.

What is the DV for vitamin D?

The DV for vitamin D is 20 mcg (800 IU) for adults and children age 4 years and older [ 26 ]. The labels must list vitamin D content in mcg per serving and have the option of also listing the amount in IUs in parentheses.

Why is vitamin D important?

Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal bone mineralization and to prevent hypocalcemic tetany (involuntary contraction of muscles, leading to cramps and spasms). It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts [ 1-3 ].

Where does vitamin D come from?

Vitamin D comes in 2 forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D2 is from plant sources. It is found in fortified food and some supplements. Vitamin D3 is produced by sunlight on the skin. It is also found in some animal foods and supplements.