Many people, men and women, young and old, have Vitamin D deficiency. Most people do not know they have this condition, but it is very common in Western cultures. The problem stems from a lack of sunlight exposure on a daily basis. It can impact a wide range of bodily functions including hair growth and health. The good news is that it can often be fixed with improved access to this nutrient. What should you know about Vitamin D and how should you correct this problem?