Every place on earth has its own endemic health hazards. You're going to need protection strategies wherever you live. As protection strategies go, taking vitamin D pills is unusually cheap, safe and effective.
So for every place on earth a different pill?
How about adjusting lifestyle to living conditions?
Vitamin D pills are in no way a surrogate for outside activities. Those give you fresh oxygen, nature, exercise, sun and so much more than any superficial pill.
But some places don't have enough sunlight for people to get adequate vitamin D, and some people (pregnant women; people with very pale skin; children under 5) don't get enough time in the sun to get vitamin D.
Combine that with advice (which is perhaps being taken a bit too rigorously by some) to avoid skin cancer and you can understand that a few people are not getting enough vitamin D.
It's great if someone can get 15 minutes of bright sunlight every day. But if they can't there's nothing wrong with a supplement.
People living in Scotland are at risk of too little vitamin D, especially during the winter months, especially if they are fair skinned or if they wear clothing which restricts sunlight (burqas etc).
I agree that overdose is a risk. I'm not suggesting mega dosing with vitamin supplements. I'm suggesting that a few people (the few people who don't have access to 15 mins bright sunlight per day) would benefit from Vitamin D supplements.
Fair skin helps absorb vitamin D. But people with fair skin are warned more heavily about sunburn, and they tend to cover up and use sun block.
But you're right, I should have been clearer. People in Scotland (where the sun is only strong enough between April and September) with dark skin are also at risk of not enough vitamin D.
