top of page

Vitamin D

In Brief



By Stefanie Schwartz, MS, RD, CDN, and Richard Strongwater, MD

Forms of Vitamin D
Vitamin D4 is present in certain mushrooms but may not be converted to calcitriol and the benefits in humans is uncertain.

Vitamin D is a group of fat-soluble vitamins (D2 ergocalciferol and D3 cholecalciferol).

Cholecalciferol (D3) is produced endogenously when ultraviolet rays hit the skin and trigger vitamin-D synthesis from cholesterol.

The liver then converts vitamin D3 to calcidiol, and then the kidneys convert calcidiol to the active form (calcitriol).

Vitamin D2/D3 is also found naturally in ...


Members can read the full Vitamin D In Brief article on

There are also references to Vitamin D in the CME eligible article

"COVID-19 Drugs: How Do They Work, and Do They Work?".

Not an APP member? Membership info.

Non-Members can download the Vitamin D In Brief PDF for $1.00 from our APP.


Additional Information

There are also references to Vitamin D in the CME eligible article "COVID-19 Drugs: How Do They Work, and Do They Work?".

And Vitamin D Simplified is an article written for the curious public. It explains How do we get Vitamin D, what does it do, and what happens if we get too much or too little?


  • LeFevre, M and LeFevre, N. Vitamin D screening and supplementation in community-dwelling adults: Common questions and answers. American Family Physician. 2018;97:254-260.

  • Institute of Medicine, Food and Nutrition Board: Dietary Reference Intake for calcium and D. Washington DC: National Academy Press. 2010.

  • Davis CD. Vitamin D and cancer: current dilemmas and future research needs. Am J Clin Nutr. 2008;88:565S-569S.

  • Stolzenberg-Solomon RZ, Vieth R, Azad A, et al. A prospective nested case controlled study of vitamin D status and pancreatic cancer risk in male smokers. Cancer Res. 2006;66:10213-10219.

  • Jones G. Pharmacokinetics of vitamin D toxicity. Am J Clin Nutr. 2008;88:582S-586S.

  • Horlick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96:1911-1930.

  • Ensrud KE, Ewing SK, Friedman L, et al. Circulating 25-hydroxyvitamin D levels and frailty status in older women. J Clin Endocrinol Metab. 2010;95:5266-5273.




IMIT takes pride in its work, and the information published on the IMIT Platform is believed to be accurate and reliable. The IMIT Platform is provided strictly for informational purposes, and IMIT recommends that any medical, diagnostic, or other advice be obtained from a medical professional. Read full disclaimer.

bottom of page