How Vitamins Work(2/2)

We're learning more all the time about the many ways vitamins benefit our bodies

A lot to learn about vitamins
Why do we need to "take" these molecules? You can see that the human body is equipped to create its own vitamin D, but our lifestyles have changed. People "in the wild" lived outdoors and they got sun exposure every day. Modern humans can often spend days at a time indoors, especially in the winter, with very little sun exposure. So to prevent rickets, we add vitamin D to milk and other foods just in case a child isn't getting enough naturally.
The case of vitamin C is even more interesting. You have probably noticed that dogs have absolutely no need for citrus fruits. On the other hand, human beings tend to enjoy them. In fact, if you were to become vitamin C deficient , you would think that something like an orange tastes fabulous, to the point where you might even eat the skin. The reason why dogs don't have any interest in citrus fruits is because they, like most animals, produce their own vitamin C molecules inside their own bodies. Humans, however, must get vitamin C from food.
Although we know the basics, we still have a lot to learn about vitamins. For example, we know for sure that if you don't get any vitamin C, you will die. But many people believe that if you take massive amounts of vitamin C, there is a health benefit. Is this true? Recent research suggests that it probably is not true. Vitamin K wasn't really understood until the 1970s, and we are still learning about it. There may be a few other vitamins lurking out there waiting to be discovered.

Vocabulary Focus
in the wild (prep. phr) ---in natural conditions, or in an area that is not cultivated and has few people living in it
just in case (adv. phr) ---because of a possibility of something happening or being needed
the basics (n. phr) ---the simpled and most important facts, ideas or things connected with something
lurking out there (phr. v) ---to exist although it is not always noticeable