Skip to comments.Excessive Vitamin D Intake May Elevate A Fib Risk
Posted on 02/04/2012 12:51:48 PM PST by neverdem
ORLANDO People with an excessive blood level of vitamin D from overdosing with supplements had a 2.5-fold increased incidence of atrial fibrillation(A Fib), based on a study of 132,000 residents of Utah and southeastern Idaho.
The finding "suggests the need for caution with vitamin D supplementation and the need for careful assessment of serum levels if high doses [of vitamin D] are used," Megan B. Smith said at the annual scientific sessions of the American Heart Association.
The finding also suggests that patients identified with new-onset atrial fibrillation should be evaluated for a possible extremely high vitamin D level, said Ms. Smith, although in the results she reported, the high blood level of vitamin D linked with a significantly elevated incidence of atrial fibrillation, greater than 100 ng/dL, was extremely unusual, occurring in just 291 of the 132,000 people (0.2%) included in the study.
Although the mechanism linking such an extremely elevated blood level of vitamin D to a markedly increased rate of new-onset atrial fibrillation remains unclear, a likely explanation is the hypercalcemia that vitamin D toxicity can cause. Hypercalcemia can, in turn, reduce cardiac conduction velocity and shorten cardiac refractory time, said Ms. Smith, a dietician at Utah State University in Logan.
"Utah [residents have] tremendous use of supplements. From what weve seen in the charts we have, excessive use of vitamin D supplements is the primary driver" of the high levels seen, said Dr. T. Jared Bunch, director of electrophysiology research at the Intermountain Medical Group in Murray, Utah, and lead investigator for the study. "The few patients [with very high vitamin D levels] who I have seen got vitamin D in their milk, from a multivitamin, and from vitamin D pills. They get it from multiple sources," but added that the low prevalence of levels above 100 ng/dL also showed that it is a difficult level for a person to reach.
"Utah has an enormous problem with vitamin D deficiency, so we had this large group of people" who were members of Intermountain Healthcare, and had their vitamin D level measured once as part of their routine care. A survey by Dr. Bunch and his associates showed that unless asked, people dont usually tell their physician that they take a vitamin D supplement, and that physicians at Intermountain Health do not usually ask patients about their vitamin D intake.
The measurement numbers documented the extent of the vitamin D deficiency problem, with 38,000 of the 132,000 people measured (29%) having a blood level below 20 ng/dL. This group with vitamin D deficiency showed significantly elevated prevalence rates of diabetes, hypertension, coronary artery disease, heart failure, and depression, compared with people in the designated "normal" vitamin D range of 41-60 ng/dL. But notably the incidence of atrial fibrillation in the deficiency group was not significantly different than the rate in the reference group with a normal vitamin D level at baseline.
"There is something unique" about the excess, toxic level, for atrial fibrillation incidence, Dr. Bunch said in an interview.
To better examine the potential role of vitamin D in elevating atrial fibrillation risk, Dr. Bunch and his associates are now regularly measuring blood vitamin D levels in Intermountain Healthcare members and prospectively tracking their atrial fibrillation incidence.
The results reported by Ms. Smith came from a retrospective analysis of the one-time vitamin D measurement by an immunoassay, and atrial fibrillation incidence tallied over an average 584 days of follow-up based on ECG testing and ICD-9 codes in each persons medical record. The most common vitamin D level measured was 21-40 ng/dL, in 73,547 people (56%). Another 17,234 people (13%) had a level of 41-60 ng/dL, which the researchers considered normal and which they used as the reference group.
During follow-up, the incidence of new-onset atrial fibrillation was about 1.5% in all subgroups based on their baseline vitamin D level, except for those with a level above 100 ng/dL, who had an incidence of about 4%. A multivariate analysis that controlled for baseline differences in demographics identified a significantly elevated atrial fibrillation rate only in people with a baseline vitamin D level greater than 100 ng/dL.
Ms. Smith and Dr. Bunch said that they had no disclosures.
See comment# 1.
I take 10,000 IU daily and can’t remember the last time that I was sick. I started taking it when my PSA was at 5.6 and today it is 0.2.
That's only one potential cause of many, obviously.
Wisconsin residents: this is not what you think! (WI-IL joke)
Actually I saw the author took one sentence to note most of the problems are not having enough. But the whole slant of the article is too much. This just falls along the same lines of other articles that are anti-supplement, people cant be trusted to take care of themselves with supplements crap.
Bottom line - supplements are far safer than OTC and prescription drugs, hands down. You can take a whole bottle of vitamin D and it won’t kill you. You can’t say the same for regular tylenol. Or just about any other drug. Supplements are far safer, and have far fewer and milder side effects, if any. Most you pee the excess out. Not so with drugs.
You were pinged for two reasons. First, there can be too much of a good thing, i.e. vitamin D. Second, for the newer members of the diabetes list, there can be too little of a good thing, i.e. vitamin D. The blood test is called serum 25-hydroxyvitamin D. You may find variations on that, e.g. 25-hydroxyvitamin D, 25hydroxyvitamin D, 25-hydroxyvitaminD, 25hydroxyvitaminD, etc.
I also would like to know the safe dosage
God knew what He was doing when He made food, and added vitamins in very, very small doses.
Frankly, I don’t find this report at all persuasive. There are numerous benefits to taking vitamin D, and this article does not persuade me of the contrary.
The effect being investigated is said to be “extremely unusual, occurring in just 291 of the 132,000 people (0.2%) included in the study.” Zero point two percent. I would imagine that that is less than the margin of error.
Not only that, but they never explain what “excessive” means. I take about 4,000 i.u. daily in the winter, and I doubt that that is excessive, although it is above the recommended dosage—which was based on research from ten or twenty years ago, and very cautious as well. And I gather from some of the comments that excessive is probably, well, quite a lot more than that.
Sounds suspiciously like a Big Pharma scare story to me.
Don’t believe this. Or, if it’s true, the percentage of people affected is so low it doesn’t make a difference.
I have been taking 5000IU of D3 per day for years. The only side effect I’ve noticed is a complete lack of illness. My Dr. thinks I’m nuts. But, then, he has a stake in my having to visit him when I’m sick.
White or chocolate?
Cue the little "That's racist" guy
You are not the only one! LOL
Tell I dug into the story.
AF is linked to several cardiac causes, but may occur in otherwise normal hearts. Known associations include:
Hypertension (High blood pressure)
Primary heart diseases including coronary artery disease, mitral stenosis (e.g. due to rheumatic heart disease or mitral valve prolapse), mitral regurgitation, hypertrophic cardiomyopathy (HCM), pericarditis, congenital heart disease, previous heart surgery
Lung diseases (such as pneumonia, lung cancer, pulmonary embolism, sarcoidosis)
Excessive alcohol consumption (”binge drinking” or “holiday heart syndrome”). Even otherwise healthy middle-aged women who consumed more than 2 drinks daily were 60% more likely to develop AF.
Carbon monoxide poisoning
Dual-chamber pacemakers in the presence of normal atrioventricular conduction.
A family history of AF may increase the risk of AF. A study of more than 2,200 AF patients found that 30 per cent had parents with AF. Various genetic mutations may be responsible.
I would add rapid hypertensive medication titration to the above Wikipedia list.
I have a mild cold right now. I don’t remember the last cold I had but it’s been quite a while. I have taken 5000 IU Vit. D3 for 3 years.
Yeah, you can get sick, but with your blood d at 60 you won’t unless it’s really infectious or you’re run down a little. My athlete son got hit with a stomach bug too.
I always wonder why docs never advise vit d. Not even for children who are constantly sick. It really helps.
You have to go get a blood test first. Then add some supplementation if it’s low. Then after a couple months, go test again. Adjust your dose if you start getting a lot of sun too.
Thanks for the ping. I have suspected that vitamin D may adversely effect the heart. I sure hope they do more research into this since so many docs recommend this supplement to their patients.
Short of carbon monoxide poisoning, everything on that list is caused by mag deficiency. Magnesium makes approximately 350 other nutrients, enzymes, etc., work in your body. We are almost ALL deficient in mg as they no longer fertilize with it, we drink too much filtered water and we eat too much processed food.
There is a fantastic book out by Dr. Carolyn Dean called ‘The Magnesium Miracle’ that really gets deep into the benefits of mag.
I know the tendancy for some is to minimize it’s positive effects but I can tell you the list of every day ailments many of us suffer from are directly related to low mg.
My doctor is in a group that recommends Vit D and even sells it in 1500 unit gel caps over their counter at check out