Most of our foods fall into that category. It's unfortunate. But, yes, natural sources are best. If we could get milk straight from the cow (non-pasturized), we'd be a lot healthier. Any natural foods (not gmo) that have the vitamins we need, in this case D, are the best things for our bodies and our minds. We are fortunate that our bodies can produce the vitamin D naturally from what the sun gives us.
We need to spend MORE time outside and less time kept trapped away in our homes and workplaces. Freedom = Health = Overall Happiness