All about Vitamin D

Updated: Apr 24, 2023

The diefinition of vitamin D and the interpreation of the vitamin D level

What is 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 dietary supplement.

How is it made?

It is also produced endogenously when ultraviolet (UV) rays from sunlight strike the skin and trigger vitamin D synthesis.

Vitamin D has two main forms, D2 (ergocalciferol) and D3 (cholecalciferol), that differ chemically only in their side-chain structures, Both forms are well absorbed in the small intestine.

The importance of vitamin D in a human body

The main role of vitamin D in human body is to regulate the calcium use to support the formation of the bones. The receptors in a small bowel enterocytes enhance calcium and phophosrus absorption, and bone receptors stimulate mineralization of newly formed bone.

Other fucntions of vitamin D

Function	Deficiency
Modulates immun system and pro-inflammatory cytokines = Reduction of inflammation	Arthritis, lupus, IBS, Multiple sclerosis
Inhibits cell growth / agniogenesis / differentiation	Cancer (prostate, breast, colon)
Glucose metabolism / pancreatic B-cell function / Insulin sensitivity	Diabetes mellitus
Influences smooth muscle tone, endothelium cardiomyocytes, controls intracelllar Ca+, RAAS	Cardiovascular disease, hypertension, stroke
Anti-oxidative / neuroprotective	Dementia, Alzhehimer's, schizophrenia, depression
The main role of vitamin D in human body is to regulate the calcium use to support the formation of the bones. The receptors in a small bowel enterocytes enhance calcium and phophosrus absorption, and bone receptors stimulate mineralization of newly formed bone.	Myofasial pain, Musuloskeletal pain, myopathy

What happens if vitamin D levle is too high or Low?

Vit D Deficiency	Vit D Excessive
Rickets	Calcification of soft tissue
Poor absorption	Renal failure
Short Bowel Syndrome
Antiepileptic treatment
Biliary cirrhosis (liver disorder)
Nephrotic syndrome
osteomalacia
Decreased 1,25-(OH) Vitamin D when PTH synthesis secrtion is impaired
Aging
Obesity (Body mass index > 30 kg/square meter)

What is normal reference range for vitamin D?

There are several recommendations on the vitamin D deficiency

nmol/L	Vitamin D Council	Endocine Society	Food and Nutrition Board	Testing Laboratories
Deficient (ng/mL)	0 - 30	0 - 20	0 - 11	0 - 31
Insufficient (ng/mL)	31 - 39	21 - 29	12 - 20
Enough (ng/mL)	40 - 80	30 - 100	> 20	32 - 100
Excessive (ng/mL)	> 150