Vitamin D bioavailability: state of the art

Crit Rev Food Sci Nutr. 2015;55(9):1193-205. doi: 10.1080/10408398.2012.688897.


There has been renewed interest in vitamin D since numerous recent studies have suggested that besides its well-established roles in bone metabolism and immunity, vitamin D status is inversely associated with the incidence of several diseases, e.g., cancers, cardio-vascular diseases, and neurodegenerative diseases. Surprisingly, there is very little data on factors that affect absorption of this fat-soluble vitamin, although it is acknowledged that dietary vitamin D could help to fight against the subdeficient vitamin D status that is common in several populations. This review describes the state of the art concerning the fate of vitamin D in the human upper gastrointestinal tract and on the factors assumed to affect its absorption efficiency. The main conclusions are: (i) ergocalciferol (vitamin D2), the form mostly used in supplements and fortified foods, is apparently absorbed with similar efficiency to cholecalciferol (vitamin D3, the main dietary form), (ii) 25-hydroxyvitamin D (25OHD), the metabolite produced in the liver, and which can be found in foods, is better absorbed than the nonhydroxy vitamin D forms cholecalciferol and ergocalciferol, (iii) the amount of fat with which vitamin D is ingested does not seem to significantly modify the bioavailability of vitamin D3, (iv) the food matrix has apparently little effect on vitamin D bioavailability, (v) sucrose polyesters (Olestra) and tetrahydrolipstatin (orlistat) probably diminish vitamin D absorption, and (vi) there is apparently no effect of aging on vitamin D absorption efficiency. We also find that there is insufficient, or even no data on the following factors suspected of affecting vitamin D bioavailability: (i) effect of type and amount of dietary fiber, (ii) effect of vitamin D status, and (iii) effect of genetic variation in proteins involved in its intestinal absorption. In conclusion, further studies are needed to improve our knowledge of factors affecting vitamin D absorption efficiency. Clinical studies with labeled vitamin D, e.g., deuterated or (13)C, are needed to accurately and definitively assess the effect of various factors on its bioavailability.

Keywords: 25-hydroxyvitamin D; Cholecalciferol; absorption; bioaccessibility; ergocalciferol; intestine.

Publication types

  • Review

MeSH terms

  • Aging / metabolism
  • Biological Availability
  • Cholecalciferol / pharmacokinetics
  • Dietary Supplements / analysis
  • Ergocalciferols / pharmacokinetics
  • Fatty Acids / metabolism
  • Food, Fortified / analysis
  • Humans
  • Intestinal Absorption*
  • Lactones / metabolism
  • Orlistat
  • Risk Factors
  • Sucrose / analogs & derivatives
  • Sucrose / metabolism
  • Vitamin D / analogs & derivatives*
  • Vitamin D / metabolism
  • Vitamin D / pharmacokinetics*


  • Ergocalciferols
  • Fatty Acids
  • Lactones
  • Vitamin D
  • Cholecalciferol
  • Sucrose
  • sucrose polyester
  • Orlistat
  • 25-hydroxyvitamin D