When ultraviolet rays from the sun comes in contact with ergosterol, a fluid found just under the skin, they convert it to vitamin `D`, which is absorbed into the bloodstream. Ten minutes of daily exposure to sunlight will supply us with the entire vitamin `D` that we need. The principal function of vitamin `D` is to promote calcium absorption in the gut and calcium transfer across cell membranes. This contributes to strong bones and a contented nervous system. Ultraviolet light converts cholesterol in the skin to vitamin `D`. This vitamin is essential for the proper handling of calcium in the body and thus in the prevention of rickets and adult osteomalacia. Interestingly, people cant overdose on natural vitamin `D` from the sun, even with day-after-day exposure, whereas synthetic vitamin `D` supplements can easily cause vitamin `D` toxicity.
Osteoporosis afflicts greater numbers of women at a younger age each year. Recent Mayo Clinic statistics reveal that one of every four women older than 45 and nine of 10 women over 75 suffer from varying degrees of osteoporosis. It is caused by stress and changes in the endocrine system, and is accelerated by the lack of calcium, protein, vitamins, minerals and essential enzymes needed by the bones to stay solid. Nutritionist Sam Zeiler says a healthy diet, physical exercise and sunshine (vitamin `D`) are essential to get rid of problems in the endocrine system.