Posted on 03/08/2010 5:33:34 PM PST by neverdem
SNOWMASS, COLO. — Serious questions exist about the safety and efficacy of the popular practice of high-dose vitamin D supplementation across a broad swath of the population.
One of these concerns is that not all of the extra calcium absorption promoted by boosting vitamin D is going into bone to prevent fractures. Some of it may actually be taken up by atherosclerotic plaque, increasing the risk of cardiovascular events, Dr. Lenore M. Buckley cautioned at a symposium sponsored by the American College of Rheumatology.
This is of particular concern in patients with known coronary disease and for those at high risk, including individuals with rheumatoid arthritis, systemic lupus erythematosus, diabetes, or psoriasis, added Dr. Buckley, professor of internal medicine at Virginia Commonwealth University, Richmond.
Discussing findings from a recent cross-sectional study involving 340 African American patients with type 2 diabetes, Dr. Buckley said that serum 25-hydroxyvitamin D levels were positively associated with increased calcified atherosclerotic plaque in the aorta and carotid arteries (J. Clin. Endocrinol. Metab. 2010 Jan. 8, 2010; [doi:10.1210/jc.2009-1797]
“The effects of supplementing vitamin D to raise the serum 25-hydroxyvitamin D level on atherosclerosis in African Americans are unknown. Prospective trials are needed,” the investigators said.
Recently, a large prospective randomized trial assessed the effects of using calcium supplements on vascular event rates, but it did not involve African Americans. The trial involved 1,471 healthy postmenopausal New Zealand women who were randomized to receive either supplemental calcium or placebo.
By 5 years of follow up, there were a total of 101 myocardial infarctions, strokes, and sudden deaths in 69 women in the supplemental calcium group compared with 54 such events in 42 control subjects (BMJ 2008;336:262-6).
The numbers needed to treat (NNT) were “particularly disturbing,” in Dr. Buckley's view.
The NNT required for 5 years of supplemental calcium to cause one additional MI, compared with placebo, was 44. The NNT for one stroke was 56. And the NNT to cause one additional cardiovascular event was 29. In contrast, the NNT to prevent one symptomatic fracture was 50.
The vascular event rate was higher in women with high compliance with calcium supplementation. The event rate was also higher during months 30-60 of follow-up, which is consistent with an initial latent period during which undetected vascular damage may occur.
There is a noticeable, if anecdotal, increase in the number of physicians ordering serum vitamin D tests to screen for deficiency. The vitamin D assay has become one of the most-ordered lab tests in the U.S., despite the assay's questionable reliability, its $40-$200 cost, and considerable unresolved debate as to what constitutes an optimal blood level.
In fact, the Centers for Medicare and Medicaid Services is considering denying Medicare coverage for vitamin D tests for screening purposes, according to Dr. Buckley.
There is solid evidence that vitamin D supplementation reduces fracture risk in the elderly, especially in those with low serum levels. But the impetus for the upsurge in vitamin D screening and supplementation is the hope that it might protect against a broad range of chronic diseases, including cancers, dementia, autoimmune diseases, and cardiovascular disease. However, that hope is driven mostly by epidemiologic data, which must be viewed as hypothesis-generating rather than definitive.
The classic example of how misleading epidemiologic associations can be is the expectation that estrogen replacement would reduce cardiovascular risk in postmenopausal women; when the Women's Health Initiative and other prospective trials were eventually carried out, it turned out just the opposite was true, Dr. Buckley noted.
“The question we have to ask is: What does that low serum vitamin D level mean? Is it the thing that predisposes, or is it somehow a byproduct of illness?” she said.
There is intriguing evidence to indicate the optimal level of vitamin D to promote bone health, muscle strength, immunity, and other key functions may vary by race. Data from the National Health and Nutrition Examination Survey show that very few white children aged 1-12 years are vitamin D deficient using the classic threshold of 15 ng/mL. In contrast, about 10% of non-Hispanic black 1- to 6-year-olds are vitamin D deficient, as are close to 30% of those in the 7- to 12-years-old age bracket (Pediatrics 2009; 124: e362-70 [doi:10.1542/peds.2009-0051]).
Many observers see this racial disparity as a public health problem reflecting unequal access to services. But there is a conundrum here: If vitamin D deficiency is rampant in black children, why do they have greater bone strength and muscle mass, on average, than white children?
Such observations make “one wonder whether the definition of normal levels should vary by race,” according to the rheumatologist.
Support for this theory comes from studies showing that pushing serum vitamin D levels to 30 ng/mL or higher in whites reduces their parathyroid hormone levels, while pushing levels above 20 ng/ml in African Americans—young or old—doesn't further decrease parathyroid hormone or increase bone density.
Asked by audience members what she does about vitamin D in her own practice, Dr. Buckley said she generally tries to get patients into the 20-29 ng/mL range, while in African Americans and patients with known cardiovascular disease she aims for 15 ng/mL or slightly more—“and I worry that might be too high sometimes.”
Dr. Buckley added that she reserves expedited supplementation—50,000 IU weekly for 8 weeks—mainly for vitamin D deficient elderly patients at high risk for fracture or fall. That's where there is supporting evidence of benefit. There is no evidence to support supplementation in young or middle-aged patients whose increased fracture risk is decades away.
Like many others, Dr. Buckley eagerly awaits fresh guidance in the form of updated recommendations on vitamin D from the Institute of Medicine.
Rumor has it that the IOM report, due this spring, will recommend an increase in the currently recommended supplemental 400 IU/day for 50- to 70-year-olds not getting sufficient vitamin D from the sun. Her hope is the IOM will address the thorny issues of who should receive supplementation, and how fast it should be done.
Dr. Buckley reported having no financial conflicts of interest relevant to her talk.
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http://www.tahomaclinic.com/articles.shtml
You should go and read some of Dr. Wright’s articles....he’s Harvard educated and a Naturapath...and my doc.....and yes, I take Vit K....can’t tell you right now how much...50mg Vit K2, and 500mg Vit K1....
Dr. Wright saves peoples lives! Including mine.
The separate K2 is probably the best for anyone who wants more than the 1000 units of D3 in the combination tablet.
Oops...meant to take out the “can’t tell you right now how much”....cause I did tell you!
I also take a lot of Vit D3....probably about 6000-7000 a day.....will cut back when my levels reach where they should be....you can’t backfill Vit D3 under the recommended amount (about 50) with little amounts....until you reach the recommendation you usually have to take larger amounts....but check with a REPUTABLE doc who knows about Vit D3 (most don’t)
“recommended amount” should be....recommended LEVELS
I am a Type 2 Diabetic on Insulin
Also have Coronary Disease and arthritis.
I tried taking 1000IU of D3, no effect. Upped it to 2000IU per day and saw slightly better blood sugar readings. I went to 5000IU of d3 and I had the best sugar control I have had in 2 years. The downside was I also had constant diarrhea. That ended my experimentation with D3. [grumble]
I went over this with my Endo. My next blood draw (later this month) will include a test for vitimin D levels.
Maybe McCain can outlaw Vitamin D to protect us from our own free will.
Cod Liver Oil also has Vitamin A. Too much Vitamin A can be toxic, and different brands of Cod Liver Oil have different amounts. Better to get Vitamin D from the sun, and second, from a supplement (Cholecalciferol-Vitamin D3).
Cod liver oil: http://www.vitamindcouncil.org/newsletter/2008-december.shtml
I don’t think science is the only reason we live good long lives.
I think good behavior is another reason.
Some of the antipathy towards Science! is that we have been sold global warming by its bigwigs for a number of years. Science! pushes global population explosion theories, it warned of the coming ice age in the 70s, and I ate margarine exclusively as a child because “butter is bad for you.”
So most of us want to take what Science! says with a grain of salt, and be cautious about accepting everything we are told as inspired truth. It’s fallible, and frequently changes, and we want that acknowledged.
Vitamin D,like A, is one that is stored up. In fact, you can get a toxic amount in your system.
More and more it seems that an attempt to treat one thing, only leads to an imbalance elsewhere. And, that correlation does not prove causation. Does a low level of D cause illness, or is there something that causes some people to be unable to maintain a certain level of D in their systems? Dr. Hadler has a chapter in his book, Worried Sick, that says you are NOT what you eat. I think he may be right. All this worry over what we eat or don’t eat may have much less effect on our health than what we would wish. There is no magic diet, food, pill, or exercise that will make us live forever.
This article also seems to go back and forth between D and calcium. From what I could tell, it was the calcium supplementaion that caused the increase in MI.
Looks like the best way to get your D is to get out in the sun a bit every day.
HA....ever been to Oregon? Sun? (Although we did have some today!)
Try a different brand. My D3 supplements have 6 other ingredients.
Well, I tried. ;-)
Re: Vitamin D, health improvement, likewise.
I’m and almost senior citizen. Now being treated by a more naturopathic Osteopath.
He does his own vitamins and supplements in small batches so they’re fresh.
He put me on D and fish oil last year and I have been around sick grandkids and husband and was only mimimally affected.
Works for me.
INDEED.
I THANK GOD for it . . . I used to have chronic respiratory stuff. Rarely now.
63 years old.
thx.
In oil is supposedly more efficacious.
Anyone know where to get Vitamin B-17?
Noting.
Thanks tons. Have you had good results with that source?
Now, what was B-17 so good for?
I’ve forgotten! LOL.
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