Vitamin D2 versus Vitamin D3

A friend asks:
I'm puzzled about vitamin D. I have been taking D3, as widely recommended, but now I hear I should be taking vitamin D2. What's the story?
As far as science knows at this time, our body treats D2 and D3 exactly the same. The only difference is that D3 comes from animal sources, such as sheep fat, and D2 comes from plant sources, such as mushrooms or algae. (Note, only a very specific and specially raised mushroom contains D3.)
With many vitamins, the number at the end can signify an entirely different purpose. Vitamin K1, for example, coagulates blood. Vitamin K2 directs where calcium is stored in the body (making the difference between hard arteries or healthy bones). So K1 and K2 are entirely different!
With vitamin D, the actual function in the body is the same as far as science can tell right now, it is just that D2 is better for the environment and doesn't contribute to animal cruelty.
The most incredible things I've ever learned from reading, I learned from stories. Stories are more memorable. They create images and time-lines in our minds. They give us all the background information that lead up to a great moment, a great realization, a great break-through.
In reality, we only truly grasp ("grok") something through personal experience. We can not add to our experience through reading dry data. But we really can and do add to our experience with stories. The more detailed, authentic, and dynamic the story, the more there is for us to learn from it. The more it resonates with us and touches us, the more we retain what we've learned.
It is because of this that I'm writing my own life as a series of autobiographical novels. If this interests you, please sign up at left and visit my patreon page for exclusive access to my personal revelations, diary entries and autobiographical novels as I'm writing them. You'll also get a lot of other awesome perks, which you can read about here: www.patreon.com/Raederle.