Sunlight on the skin causes vitamin D to be formed in the body. For white individuals, as little as 15 minutes of sunlight a day on the skin is usually enough. It is probably worthwhile for those who get little sunlight to take a supplement. Dark-skinned and black individuals do not convert sunlight into vitamin D so they need to get vitamin D in their food or supplements. Calcium comes in many forms and dosages.
Calcium carbonate is the cheapest and safest.
The simplest thing is to drink a quart of vitamin D fortified milk each day. Choose the low-fat type. For those compulsive individuals who want to know the exact recommendation, the following 1997 guidelines have been published by the Institute of Medicine. For further information on calcium, go to the Diet Section of Patient Education and click on Osteoporosis Diet . You don't have to worry about these as there is plenty in the regular foods you eat.