Sunlight exposure is the best way to get Vitamin D. The body regulates naturally the quantity of Vitamin D produced from sunlight. The process is complex and deals with cholesterol regulation (control and conversion) and sweat.
According to http://www.vitaminsinamerica.
Don’t be afraid to get sweaty in the sun. And don’t rush to take that shower. Your body is busy producing vitamin D, the sunshine vitamin.
The benefits if vitamin D are numerous : healthy teeth, stronger bones, regulating immune defense system, improve cognitive functions, help maintain healthier body weight, and protect from radiation damage.