What is Vitamin D3?

Vitamin D (ergocalciferol-D2, cholecalciferol-D3, alfacalcidol) is a fat-soluble vitamin that helps your body absorb calcium and phosphorus. Having the right amount of vitamin d, calcium and phosphorus is important for building and
keeping strong bones. Vitamin D is used to treat and prevent bone disorders (such as rickets, osteomalacia). Vitamin D is made by the body when skin is exposed to sunlight. Sunscreen, protective clothing, limited exposure to sunlight, dark skin, and age may prevent getting enough vitamin D from the sun. Vitamin D with calcium is used to treat or prevent bone loss (osteoporosis).

Vitamin D is also used with other medications to treat low levels of calcium or phosphate caused by certain disorders (such as hypoparathyroidism, pseudohypoparathyroidism, familial hypophosphatemia). It may be used in kidney disease to keep calcium levels normal and allow normal bone growth.

Vitamin D drops (or other supplements) are given to breast-fed infants because breast milk usually has low levels of vitamin D.

That being said, it can be worth understanding how vitamin D2 and D3 specifically are different from each other—so here’s a quick rundown:

• Vitamin D3 is the form of vitamin D the human body makes when sunlight strikes the skin. The body can’t manufacture vitamin D2.
• Vitamin D3 is found in animal sources of foods, like fatty fish and fish oil, liver, organ meats, and egg yolks.
• Vitamin D2 primarily comes from plant sources (like wild mushrooms), and forms when certain kinds of plants are exposed to ultraviolet light from the sun.
• Vitamin D2 is also less expensive to produce, so it is the form most commonly used to fortify foods, like milk, cereal products, and orange juice

Vitamin D also regulates many other cellular functions in your body. Its anti-inflammatory, antioxidant and neuroprotective properties support immune health, muscle function and brain cell activity.

Now let’s look at some evidence…
Research on vitamin D use for specific conditions shows:

• Cancer. Findings on the benefits of vitamin D for cancer prevention are mixed. More studies are needed to determine whether vitamin D supplementation may reduce the risk of certain cancers.
• Cognitive health. Research shows that low levels of vitamin D in the blood are associated with cognitive decline. However, more studies are needed to determine the benefits of vitamin D supplementation for
  cognitive health.
• Inherited bone disorders.Vitamin D supplements can be used to help treat inherited disorders resulting from an inability to absorb or process vitamin D, such as familial hypophosphatemia.
• Multiple sclerosis. Research suggests that long-term vitamin D supplementation reduces the risk of multiple sclerosis.
• Osteomalacia. Vitamin D supplements are used to treat adults with severe vitamin D deficiency, resulting in loss of bone mineral content, bone pain, muscle weakness and soft bones (osteomalacia).
• Osteoporosis. Studies suggest that people who get enough vitamin D and calcium in their diets can slow bone mineral loss, help prevent osteoporosis and reduce bone fractures. Ask your doctor if you need a calcium and vitamin D supplement to prevent or treat osteoporosis.
• Psoriasis. Applying vitamin D or a topical preparation that contains a vitamin D compound called calcipotriene to the skin can treat plaque-type psoriasis in some people.
• Rickets. This rare condition develops in children with vitamin D deficiency. Supplementing with vitamin D can prevent and treat the problem.