I really enjoyed the fact how informative of your post is, but I disagree with one thing about it. Vitamin D supplementation may be needed even for the "average" person, especially during winter time in Northern countries. At this time of the year it's practically impossible to get adequately sunlight for vitamin D synthesis, since sunlight isn't a self-evidence. Therefore many people suffer from vitamin D deficiency in winter. So, supplements aren't always that bad but rather beneficial. :)