I take vitamin D3-2000 and Centrum vitamins for adults over 50 which has 400 IUs of vitamin D. I recently purchased Caltrate 600 with Vitamin D3, 1600 IUs per day. Is this a toxic amount of vitamin D? Or, should I ditch the Vitamin D3-2000, taking the Caltrate 600-D and Centrum vitamins only?

I think it depends on how your body processes Vit D. I was on a prescription strength 100,000IU a week for several months. I've been on 50,000IU every other week for several years and my level is barely normal. I've recently added 5,000IU a day to try to get my levels up to where I stop having body aches. My levels are still low because my body doesn't process it correctly. I don't think 1,600IU per day is that much. It takes 50,000IU daily over several months to build up a toxicity (source: Mayo Clinic).