Show Summary Details
Page of



Tom R. Hill

, and David A. Bender

Page of

PRINTED FROM OXFORD MEDICINE ONLINE ( © Oxford University Press, 2021. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 03 March 2021

The vitamins are a disparate group of organic compounds that are required in small amounts (mg or µg per day) for the maintenance of normal health and metabolic integrity. Four vitamins (A, D, E, and K) are lipid soluble, while the others are water-soluble. Determining how much of any particular vitamin is required for health is not straightforward, a standard technique being to deprive volunteers of the vitamin in question until there is detectable metabolic change and then replete with graded doses of the vitamin until normal metabolism is restored, with the reference intake (recommended daily intake or amount or recommended dietary allowance) set at 2× standard deviation above the average requirement.

Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Public users are able to search the site and view the abstracts for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.