To make it more confusing every so often my blood pressure would randomly drop back to normal and stay there for a few days so it was clear that my high blood pressure was not due to obstructed arteries or kidneys.
As so often happens, my family doctor did one round of tests and then sent me to a nephrologist who was supposed to be an expert in blood pressure. The nephrologist did another round of tests and sent me to my endocrinologist. The endo did yet another round of tests that came up blank and then told me that such cases were extremely difficult to diagnose and that my insurer would not pay for the next step which involved going to an expert at a major hospital outside of our rural region.
Fortunately, a health news item came across my screen that gave me some insight into what was going on. It described a condition called "Milk Alkali Syndrome" which after many years of nonexistence had come roaring back. The syndrome causes high blood pressure and kidney problems.
You can read about Milk Alkali Syndrome in this summary posted on Diabetes in Control:
Calcium Supplements Can Increase Risk of Kidney Failure
Though the study makes it sound as if the problem is caused by calcium supplements, close reading reveals that it caused by the combination of high calcium and high Vitamin D and that the recent spike in cases has been caused by the recent fad of people supplementing with high levels of Vitamin D.
I have been supplementing with Vitamin D for three years at my doctor's suggestion because I am a melanoma survivor and there's some data suggesting Vitamin D fights melanoma. I had achieved a level of 39 ng/ml a year ago, taking 1000 IU a day so I had raised the dose to 2000 IU because I'd been influenced by some vocal online doctors to believe that higher was better.
When I dug out my many recent lab tests I found that my family doctor had tested my calcium level. It was NOT flagged as abnormal. The range for blood calcium went up to 10.3. But even so, My blood calcium was 10.3. So while my calcium level was normal, it was just barely normal.
Further research revealed that taking diuretics (which I was doing in an attempt to lower my very high blood pressure )lowers blood calcium. So that "normal" reading was almost certainly lower than the blood calcium level I'd had a few weeks before.
Hunting for previous values I found one from before I supplemented with Vitamin D which was in the 8s. Much more normal.
I do not supplement with calcium. I stopped after reading about the Aukland Study described further on in this post). But I do eat a lot of cheese. I had already noticed that there seemed to be some link between my blood pressure and my cheese intake, but I had thought this might have something to do with a factor found in aged cheese that has also been associated with elevated blood pressure. As a result, I'd cut back on aged cheese, but not all cheese.
When I looked at my latest Vitamin D test I found it showed my Vitamin D to be 55.8 ng/dl. The test a year and a half earlier when I'd been taking only 1000 IU a day had been 39 ng/dl. My doctor had thought 55.8 an excellent level, but recent research suggests that more is not necessarily better when it comes to Vitamin D levels.
All of a sudden, my mysterious symptoms started to come into focus. I had two "normal" lab results that were no more "normal" than a 2 hour glucose tolerance test result of 139 mg/dl (a result that often ignores a one hour value well over the 200 mg/dl level diagnostic for full fledged diabetes).
When I read on further, I learned that the safe ranges for Vitamin D were drawn from studies done on White males of European ancestry--and that some data suggests that people from Non-Northern European ethnic heritages have adapted to lower Vitamin D levels and that they do poorly when they attain the high blood levels suggested for White males.
More interestingly, a decently conducted three year study of older women given high dose injections of Vitamin D to avoid osteoporosis discovered that levels of blood Vitamin D corresponding to mine correlated with more not less bone fractures. You can read that study here:
Annual High-Dose Oral Vitamin D and Falls and Fractures in Older Women: A Randomized Controlled Trial. Kerrie M. Sanders. JAMA. 2010;303(18):1815-1822.
(Note that the units used in this study were nmol/L not the ng/dl labs use in the United States. Converting the units shows that these women started out deficient with average Vitamin D levels of 19.63 ng/dl, but after the Vitamin D shots their levels went up to an average 48.08 ng/dl.) We know that too much blood calcium is linked with bone brittleness, too.)
Another recent study, The Aukland Study, had found that women supplementing with calcium had more heart disease (presumably linked to calcification in their arteries) than women who didn't.
Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial. Mark J Bolland. BMJ. 2008;336:262-266 (2 February), doi:10.1136/bmj.39440.525752.BE (published 15 January 2008)
And a disturbing comment in yet a brand new study commenting on the Aukland Study really got me thinking.
there is substantial epidemiological evidence that serum calcium levels in the upper part of the normal range are a risk factor for vascular diseaseThe combination of this information with the information that Milk Alkali syndrome (high blood calcium caused by high calcium and Vitamin D intake) caused high blood pressure suggested to me that I might have found the explanation for my blood pressure problems--and that I had been, once again, the victim of another doctor-caused medical disaster!
Once I had sorted this out, I stopped taking the 2000 IU a day of Vitamin D I had been taking for the past year. I cut out all cheese from my diet--which made me realize just how much cheese I'd been eating--much more than I thought!
I had read it takes about 2 weeks to eliminate HALF the excess vitamin D in the blood and that more Vitamin D is stored in fat and slowly released, so I figured it would take a while to restore truly normal calcium levels. Even so, after ten days it looks like I might be onto something. My blood pressure has already come down--it's in the 120s over 80s rather than the 140s over 90s when I wake up and has been staying in that range most of the day instead of spiking higher.
I will be avoiding cheese for another month and tracking how my blood pressure does. When I see my endo for my regular appointment in October I'll ask for repeat Calcium and Vitamin D tests. Since I did well at the 39 ng/ml Vitamin level I'll shoot for that--but only if I can sustain that level without elevated calcium. Meanwhile, I hope I haven't inadvertantly deposited damaging amounts of calcium in my arteries and kidneys.
WHAT DOES THIS MEAN FOR YOU?
For those of you reading this who have been supplementing with Vitamin D thanks reading all the doctor-inspired hype, my message here is NOT that you should not take Vitamin D.
Instead, what I'm saying is that if you are supplementing Vitamin D you need to get your blood levels of both Vitamin D and Calcium tested periodically so you can avoid dangerous Calcium levels. 1000 IU appears to be a safer level for supplementation than anything higher, and if you don't know what your levels are you should not supplement with more until you can check those levels out.
My other point is this: if you are eating a low carb diet and also taking white, chalky pills--prescription or other supplements), be aware that you may be getting much more dietary calcium than you realize.
Since it is looking like high normal calcium levels damage both your arteries and kidneys maintaining truly normal calcium levels is probably most important than obsessing about cholesterol.
UPDATE 8/5/10: Two months after stopping ALL Vitamin D supplementation and avoiding cheese my calcium levels are back to normal and my blood pressure is far more stable. I'm gong to stick with this regimen for a few more months and only supplement D in the fall after I stop gardening each day. I'll stick with the 1000 IU level which worked well for me in the past.