Sunlight is a major source of Vitamin D, which is essential to good health. Vitamin D helps build strong bones and teeth, and ensures muscle and nerve function. It is available in fortified dairy products, fish and organ meats, but sunlight is its primary source. It is known that added light can help in very specific ways for a limited number of specific problems. Research shows that adding brighter, whiter light to dimly-lit factories and other workplaces increases productivity, especially in areas where work is done at night.
Research also indicates that good light improves efficiency in offices.
Keeping a regular sequence of day-night hours can aid circadian rhythm consistency, which helps develop better overall good health. The use of light boxes in light therapy is a proven method of treating SAD and is often used by psychiatrists for that purpose. Light boxes are sometimes used to treat jaundice in infants, and for some skin conditions. A dermatologist should be consulted, however, before using light box therapy for any skin condition. There is no clinical evidence to support claims that light therapy can treat cancer, headaches, digestion, or hyperactivity in children.