http://www.reuters.com/article/2014/07/09/us-health-cancer-bowel-idUSKBN0FE15L20140709

I like to keep my patients' Vitamin D in the top third of the "normal" range. This, and many other studies, are validating the health benefits of this very important hormone, Vitamin D. The amount of vitamin D you take should be based on lab testing. If you are unable to get your vitamin D level checked, I recommend 5000 units daily (one of our capsules daily ) until you can get your levels checked. I like to keep most of my patients Vitamin D levels between 70-100, depending on their needs and other conditions.