Sino Gallo, associate professor of nutritional sciences in the College of Family and Consumer Sciences, spoke with GQ about how much vitamin D3 people should be taking each day.
Foods like fatty fish, egg yolks and beef liver all contain vitamin D3.
“Some research has suggested D3 can raise and maintain blood vitamin D levels more effectively and for longer than D2, although if taken daily they likely act similarly. Both forms need to be converted to the active form, calcitriol, to have any biological activity in the body,” Gallo said.
This is why vitamin D3 supplements are often recommended over vitamin D2.
Getting vitamin D from the sun is more complex. UV-beta rays from the sun create a compound called dehydrocholesterol. This compound is found in the skin and is then converted to vitamin D3.
“This way of getting vitamin D is not a safe nor sustainable source of vitamin D because of its potential for skin cancer,” Gallo said.
Vitamin D3 is the preferred form of vitamin D in supplement form because it raises vitamin D levels in the body more efficiently.
“The general guidance for most healthy adults is between 600 and 800 international units a day, which is likely sufficient to prevent bone diseases. But some experts suggest higher amounts may be necessary to have any effects on non-bone health outcomes,” Gallo said.