Metabolic clearance of vitamin D after heart attack
This week, Dr. Julian Barth, and colleagues, of the University of Leeds, discovered that vitamin D levels do not decline after a heart attack. At least they do not decline beginning 2 days after the heart attack. This implies vitamin D is not being “used up” or metabolically cleared during the healing of the heart attack.
Dr. Barth studied 48 patients with an acute myocardial infarction (MI) and measured 25(OH)D levels after 2 days, 7 days, 30 days and 90 days post-MI. Inflammation was occurring during this time, as evidenced by rise and fall of CRP, but they found no relationship between CRP and 25(OH)D.
They did not measure vitamin D levels before the heart attack (understandably), so we don’t know if 25(OH)D levels declined from before to after the heart attack (that is, during the acute event). We do know they don’t decline when a damaged heart is healing. Dr. Barth cited a study that found the same thing with an acute malarial infection: vitamin D levels don’t decline during the acute phase of a malaria infection.
(The good news is that people in Leeds are going outside more than during the sun scare. In the winter average 25(OH)D levels were 9.6 ng/ml; in the spring, 15.8; in the summer 30; and in the fall 18 ng/ml, although the numbers were small.)
Compare the lack of metabolic clearance of vitamin D after a heart or malaria attack to what occurs after a knee replacement. Dr. Reid and colleagues of the University of Glasgow found 25(OH)D fell dramatically after a knee replacement. I have reported on this before.
Reid D, Toole BJ, Knox S, Talwar D, Harten J, O’Reilly DS, Blackwell S, Kinsella J, McMillan DC, Wallace AM. The relation between acute changes in the systemic inflammatory response and plasma 25-hydroxyvitamin D concentrations after elective knee arthroplasty. Am J Clin Nutr. 2011 May;93(5):1006-11. Epub 2011 Mar 16.
They measured 25(OH)D before and after a knee replacement on 33 subjects and found 25(OH)D reduced by 40% from before to 2 days after the surgery. Even at three months, 25(OH)D was still 20% lower than preoperative levels indicating, perhaps, the healing knee was “using up” or metabolically clearing the vitamin D. Again, since we don’t know what the 25(OH)D levels were before the MIs in Dr. Barth’s paper, we don’t know if acute MI’s metabolically clear any vitamin D. I suspect they do, although nothing like a knee replacement, which involves major damage to a large joint.
While we only definitively know about the effects of knee replacement surgery on 25(OH)D, I think in the meantime it’s important to be sufficient in vitamin D for lots of reasons when going to the hospital. The take home message is that if you are going into the hospital for any reason, especially surgery, make sure you have plenty of vitamin D reserves by having your 25(OH)D at around 50 ng/ml before admission.
The above article was authored by Dr John Cannell of The Vitamin D Council.