There’s more than just milk in your carton. Take a look at the ingredients on your milk jug, you’ll likely see vitamin D listed, even if the milk doesn’t advertise that it’s been fortified with a vitamin. These days, milk is almost always fortified with vitamin D and the reason dates back to the 1900s.
Rickets ,a childhood bone disorder that can lead to weak and soft bones, stunted growth and sometimes skeletal deformities, was rampant in the early 1900s. Approximately 80 % of children in Boston suffered from it. The cause of rickets is a deficiency in vitamin D or calcium. Vitamin D is synthesized in our bodies when our skin takes in the sun, and our bodies need Vitamin D to be able to absorb calcium.
“Rickets became an epidemic as you had the Industrial Revolution and with it, childhood labor,” explains Patsy M. Brannon from the division of nutritional sciences at Cornell University. Children were simply not exposed to enough sun. Since vitamin D does not naturally occur in many foods, deficiencies became widespread.
Foods that naturally contain vitamin D are cod liver and fatty fish like tuna, swordfish and salmon. But even that would not provide your body with enough vitamin D, explains Brannon. That’s why the fortification of milk with vitamin D, which began in the 1930s, still continues today ― despite it being an entirely voluntary addition from dairy companies.
According to the National Institute of Health Office of Dietary Supplements (NIH), the recommended daily intake of vitamin D is 600 International Units (IUs) for people between the ages of 1 and 79.
Source:The Huffington Post