What about Vitamin D?
Vitamin D is essential for bone health and increasingly is suspected to play a role in other health aspects, too. It is very efficiently made in the skin when exposed to UVB – just 15 minutes of exposure on the arms 3 times a week in the summer is sufficient to have enough. There is no benefit in trying to get more as the body does not store it. It is not usually in high enough concentrations in food, so the best bet is to take a supplement. The NHS recommend 10 mcg a day. This is far safer than trying to obtain it from sun exposure.