Miten on saatu selville että auringonsäteily synnyttää D-vitamiinia?Iholla.

D-Vitamiinin löysi henkilö nimeltä Elmer McCollum ( https://en.wikipedia.org/wiki/Elmer_McCollum#Discovery_of_vitamin_D )

Ilmeisesti D-vitamiinin kehitys iholla tuli selville, kun tiedemiehet yrittivät löytää parannuskeinoa riisitautiin ja huomasivat että UV säteily sai ihon tuottamaan omaa D-Vitamiinia.

"But the finding still failed to explain why rickets was so predominant in areas of little sun. (Mellanby’s dogs, in addition to eating nothing but oatmeal, had been kept indoors.)

Soon, other scientists began to show that UV light could also cure rickets by prompting the body to make its own vitamin D in the skin.

In Wisconsin, researchers found that they could cure rickets not only by exposing animals to UV light but also by exposing their food. (UV light triggers formation of a “previtamin,” which the body converts to vitamin D.) By 1924, bread and milk were being irradiated throughout the U.S.

Eventually, scientists figured out how to make vitamin D in the lab, and irradiated foods were replaced with those fortified with synthetic D."
https://www.latimes.com/archives/la-xpm-2006-jul-24-he-esoterica24-stor…