It is great to hear that you are taking proactive care of your osteopenia by boosting your Vitamin D intake! There are three different ways to get Vitamin D: food, sunlight and supplements.

However, it can be tough to get adequate amounts of Vitamin D in one's diet, unless one is particularly fond of cod liver oil. (To be fair, there is Vitamin D in egg yolks, beef liver, and fish such as salmon and sardines, as well as certain foods that are fortified with the Vitamin like milk and some breakfast cereals.)

But since most of us don't eat enough of these items to meet recommended amounts (800-1000 IUs for those 50 and older), we can evaluate our exposure to direct sunlight, unprotected by clothing or sunscreen. Even as little as 10 minutes several times a week is considered beneficial, but this may not be a suitable option for those who live in harsh climates or north of the 37th parallel, or who have reason to be especially concerned about skin cancer.

Thus for many people the best solution is a supplement. Unlike calcium, I've never come across strong data on one type of Vitamin D supplement being better than another, but many experts recommend taking the D as its own tablet rather than relying on a multivitamin, which may not have enough of this important vitamin.

Let us know what works for you!