Vitamin D: Rich Food Sources, Supplements, Deficiency Diseases

Vitamin D is one of the important fat soluble vitamin, which plays a major role in absorption of calcium, phosphorus and has a vital role in formation, ossification, and mineralization of bones. Vitamin D is present naturally only in few foods, and vitamin D can be added to food, and is also obtained from sunlight. Vitamin d is also known as Calciferol. Vitamin D in the body is present in several forms. Vitamin d is converted into active form in the body with the help of liver and kidney.

Vitamin D Facts

  • Vitamin D has number of vital functions in the body, such as maintaining adequate serum calcium level, normal phosphate concentrations, bone mineralization, preventing hypocalcemic tetany, helps in active functioning of immune system.
  • Vitamin D is biologically inert in body and it needs to undergo two hydroxylations to convert into active form.
  • The inactive form is present in the form of 7 – dehydroxycholesterol and is converted into active form in the presence of ultraviolet rays i.e. sunlight.
  • During old age human skin fails to produce vitamin D effectively.
  • Over exposure of skin to sunlight may cause sunburn and application of sunscreen lotion doesn’t favour vitamin D synthesis from sunlight.
  • 10 to 15 minutes of sunlight exposure is enough per day and in case of prolonged exposure, sunscreen lotion application is good for skin health.
  • Osteomalacia and Rickets are the main deficiency disorders of vitamin D occurs in adults and children respectively
  • Vitamin D deficiency leads to brittle, thin, soft and weak bones.
  • Vitamin D deficiency may cause schizophrenia.


Main sources of vitamin D

Natural sunlight : Exposure of skin to sunlight helps in the synthesis of Vitamin D by converting inactive form into active form.

Fortification of dietary foods : Adding vitamin D rich foods in the diet is known as fortification of dietary foods.

Oily fish : Fish and fish oil are the richest sources or vitamin D.

Mushrooms are also rich in vitamin D.

Sources of Vitamin D

  • Cod Liver Oil
  • liver and beef,
  • boiled egg
  • meat and animal origin food
  • cheese, butter
  • Salmon,
  • Mackerel,
  • Margarine fortified,
  • Sardines, canned in oil,
  • reduced fat milk
  • Cereal grain bars,
  • Pudding,
  • dried cereals

only dietary foods don’t fulfill the vitamin D requirement of the body. Exposure to sunlight is the best source of vitamin D.

Vitamin D supplementation for different groups

individuals with less sunlight exposure – 400 to 1000 units/day.

Old age, or after 65 years – 800 to 1000 units/day

Patients with cystic fibrosis – 800 to 1000 units/day

Active metabolites of Vitamin D are administered for patients with kidney disease.

Deficiency disorders of vitamin D

  • Nearly 40% US people are suffering from vitamin D deficiency.
  • Osteoporosis is caused due to poor absorption of calcium, as the deficiency of vitamin D. Osteoporosis is characterized by weak bones, increased bone fragility, etc.
  • Osteomalacia is seen in adults is characterized by weak bones prone to get fracture.
  • Rickets in children : Children between the age group of infancy to 2 years are at risk of rickets. The symptoms of rickets are retarded growth, bone deformity, tetany, muscular hypotonia, and convulsions.
  • vitamin D deficiency leads to poor absorption of other vitamins and minerals and leads to vitamin and mineral deficiency in the human body.
  • fractures may occur due to vitamin D deficiency.

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