24 Good Reasons Why You May Need Vitamin Supplements
21. Lack of Sunlight
People whose exposure to sunlight may be minimal may suffer from insufficient quantities of vitamin D needed for calcium metabolism, without which rickets and osteoporosis have been observed. The trigger for vitamin D synthesis in the skin is ultraviolet light. Clouds, rain, smog, cigarettes, ordinary window glass, curtains, and clothes block it. 400 i.u. is the overall recommended dietary dose of vitamin D supplements.
