Here in Boston, we tell people they need a more reliable source of vitamin D than the sun, especially during the winter months. A cup of milk contains about 100 international units of vitamin D , so four cups a day is ideal. But don't count on other dairy products, such as cheese, yogurt or ice cream, to fulfill your vitamin D needs. Unlike milk, these foods are not fortified with vitamin D . Do not exceed the recommended dosage of 400 international units, however.
Vitamin D is toxic in high amounts.
Graze far and wide. Bones are not made from calcium alone. They're an amalgam that includes zinc , boron and copper , among other minerals. If you smoke, stop. Monitor your medications.