Hello~Yes, it is true. Vitamin D deficiencies are common and can cause all kinds of issues. I have posted about Vitamin D on this thread, it might be under yours in fact. I highly suggest seeing a doctor (or better yet, a naturopathic physician) that truly understands and knows about the benefits of this vitamin, ask to be tested and make sure it if for D3 as that is the important one. In my opinion, it is very safe to take up to 5000IU of it daily, and to make sure the calcium isn't upset or unbalanced by it, add K2 to it as well, this should help your issues. It actually brought my husbands high blood pressure down. It is a wonderful vitamin sadly ignored by most.