Free Nutritional Health Information and Tools


Overview of Vitamins | Vitamin A (and Beta Carotene) | Biotin (Vitamin H) | Vitamin B-1 (Thiamin) | Vitamin B-2 (Riboflavin) | Vitamin B-3 (Niacin or Nicotinic Acid) | Vitamin B-5 (Pantothenic Acid) | Vitamin B-6 (Pyridoxine) | Vitamin B-12 (Cobalamin) | Vitamin C (Ascorbic Acid) | Vitamin D | Vitamin E | Folate (Folic Acid) | Inositol | Choline


Vitamin D

Functions of Vitamin D

  • Improves absorption and utilization of Calcium and Phosphorous.
  • Is required for bone and teeth formation.
  • Maintains a stable nervous system and normal heart action.

Deficiency of Vitamin D

  • Rickets in children and osteomalacia in adults.
  • Muscle weakness, bony deformities.
  • Neuromuscular irritability causing muscle spasms of the larynx (laryngospasm) and hands (carpopedal spasm), generalized convulsions and tetany.

People with an increased risk of Vitamin D deficiency

  • City dwellers or anyone subject to smog.
  • Night workers, or anyone whose clothing, environment or lifestyle keeps them out of the sunlight.

Clinical uses of Vitamin D

  • Vitamin D is useful for preventing and treating vitamin D-deficiency bone diseases (rickets in children and osteomalacia in adults).
  • 25-Hydroxyvitamin D3 is useful for treating disorders, such as severe liver failure, in which vitamin D cannot be metabolized to 25-hydroxyvitamin D.
  • The active form of vitamin D (1, 25-dihydroxyvitamin D3) and its analogs are useful for treating metabolic bone disorders due to inborn and acquired disorders in the metabolism of 1, 25-dihydroxyvitamin D2. These have recently been shown to also be valuable in treating the skin disease psoriasis.

Recommended dietary allowance for Vitamin D

See Recommended dietary allowances for vitamins.

Food sources of Vitamin D

Good food sources are milk properly fortified with vitamin D, fatty fish such as salmon and mackerel, cod liver oil, fish liver oil, some breads and cereals, and some egg yolks.

Toxicity of Vitamin D

Excessive quantities of vitamin D (in excess of 5,000-10,000 IU/day) can cause hypercalcemia, hypercalciuria, kidney stones, and soft tissue calcifications.