I have been studying and applying therapeutic nutrition for many years. I was very excited to hear the new information on Vitamin D a few years ago, so I started taking about 1,500 to 2,000 IU per day. Five years ago at 70 I found I had shrunk from 5’5” to 5’4 1/2”, so increased my intake then. I just had a complete physical, 76, and have not shrunk any more. My mother had severe osteoporosis and by my age had shrunk 2 or 3 inches. Vitamin D is very helpful for “winter depression.” I am concerned that you are taking a toxic amount, so am enclosing a link regarding toxic levels. If you are an average sized male, 2,000 should be good unless you have some unusual problem.
http://www.vitamindcouncil.org/about-vitamin-d/am-i-getting-too-much-vitamin-d/#
A can of tuna fish has about the same content of D, as 1/2 the recommended daily amount of fortified milk. There are better dietary/fish sources as shown on the list below. I looked at about 6 lists and this seemed to be the best laid out, although I disagree with their recommended allowances. Perhaps this was composed before the more recent increase in suggested amounts.
http://www.dietitians.ca/Your-Health/Nutrition-A-Z/Vitamins/Food-Sources-of-Vitamin-D.aspx
A one time the VA had me on 50,000 IU of vitamin D daily.
I'll report back on the results and conclusions from todays meeting.
BTW, I'm 71.
Doctor said reduce vitamin D3 to 20,000 IU daily, lab results are trending to the high side.