The supply of vitamin D to the German population is concerning: A study from 2008 showed that more than half suffer from vitamin D deficiency; among those over 65, even 75% are under-supplied. Such a deficiency can have consequences as severe as obesity, lack of exercise, and smoking. Just a few minutes of morning sunlight each day are enough to prevent a deficiency, a dose that is completely safe even for light-sensitive people with fair skin! It has long been known that vitamin D protects children from rickets and adults from osteoporosis. Recent studies show that vitamin D also prevents many diseases, such as cancer, heart attack, stroke, high blood pressure, diabetes, depression, and arthritis. Recently, vitamin D has been used to treat these diseases.