If you are going to take one supplement, it should be Vit D.  Especially because we live north of the 37th to 38th parallel, along with the population center of the United States.

At or above this parallel our skin makes no Vitamin D for approximately one half of the year. 

Vitamin D is crucial for:

1. Calcium absorption
2. Bone health
3. Immunity
4. Mood regulation 
5. Muscle function
6. Heart health
7. Cancer risk reduction

Get your Vit D level checked, and do that annually.

And if you are going to get some of your Vit D from direct sunlight, always put on sunscreen.

Wishes for a great day,

Each one a gift,

David/