a nutrient that the body needs in small amounts to function and stay healthy. vitamin d helps the body use calcium and phosphorus to make strong bones and teeth. it is fat-soluble (can dissolve in fats and oils) and is found in fatty fish, egg yolks, and dairy products. skin exposed to sunshine can also make vitamin d. not enough vitamin d can cause a bone disease called rickets. it is being studied in the prevention and treatment of some types of cancer. also called cholecalciferol.
出典:Wiktionary
出典:『Wiktionary』 (2026/05/07 13:11 UTC 版)
From vitamin + D (“4th letter”). From being the fourth vitamin discovered. Coined in 1922 by Elmer McCollum, who discovered the vitamin.
vitamin D (uncountable)
出典:Wikipedia
出典:『Wikipedia』 (2011/08/02 05:49 UTC 版)
Vitamin D is a group of fat-soluble secosteroids. In humans Vitamin D is unique both because it functions as a prohormone and because when sun exposure is adequate the body can synthesize it (as Vitamin D3). Measures of the serum levels refect endogenous synthesis from sun exposure as well as intake from the diet and it is believed that synthesis may contribute generally to the maintenance of adequate serum concentrations. The evidence indicates that the synthesis of vitamin D from sun exposure works in a feedback loop that prevents toxicity but, because of uncertainty about the cancer risk from sunlight, no recommendations are issued by the Institute of Medicine for the amount of sun exposure required to meet vitamin D requirements. Accordingly the Dietary Reference Intakes for Vitamin D assume that no synthesis occurs and that all of a person's vitamin D is from their diet.