New Study Warns Against Excessive Intake of Vitamin D
Fellows - As a long time member of Life Extension Foundation I have come to learn a lot over the years. I read their monthly magazine cover to cover and for most of us here I believe it would be a great value to you as well. Dr. Crisler offers a free years subscription here: http://www.lef.org/lpages/drj
I just received this email alert from LEF re D3 levels and it's possible correlation to atrial fibrillation, albeit, as you will read, may be more associated with hypothyroidism.
Nevertheless, most of us all here supplement with D3 so I thought it relevant to post this for your edification.
Also, get your free subscription to Life Extension Magazine...you can thank Dr. Crisler later;)
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Dear Member,
At the annual conference of the American Heart Association held last week, a study was presented that measured 25-hydroxyvitamin D blood levels in a very large group of Americans.1
The data corroborates what was previously published showing that those with higher vitamin D blood levels have substantially lower risks of degenerative disease. For example, those whose 25-hydroxyvitamin D level ranged from 61–80 ng/mL had a 52% reduction in diabetes risk compared to those with deficient levels (below 20 ng/mL).1
Those whose 25-hydroxyvitamin D levels ranged 81–100 ng/mL had a 36% reduction in hypertension incidence when measured against the deficient group. Compared to people in the deficient range, those with higher blood levels of 25-hydroxyvitamin D had significantly lower risk of heart failure, depression, coronary artery disease, kidney failure and prior stroke.1
There was a warning issued, however, when 25-hydroxyvitamin D exceeded 100 ng/mL. These individuals showed a much higher risk of atrial fibrillation.
Even though the data presented at the American Heart Association conference is not yet published, we are sending this advisory to our members to ensure they maintain sufficient 25-hydroxyvitamin D levels to protect their health, but not exceed upper limit levels long ago established by Life Extension® and mainstream medicine.
How This Study Compares to Life Extension's Protocol
In the January 2010 issue of Life Extension Magazine®, we reported startling findings that 85% of our members had less than optimal levels of vitamin D in their blood (as measured by 25-hydroxyvitamin D).
Based on a large volume of published data, we recommended that the optimal range of 25-hydroxyvitamin D to protect against disease is between 50–80 ng/mL. Yet the vast majority (85%) of our dedicated members were below 50 ng/mL.
A young person who spends many hours in the summer sun often has 25-hydroxyvitamin D levels greater than 60 ng/mL, yet as people age their skin converts less sunlight into vitamin D. There are also absorption problems aging people encounter that usually requires they supplement with 5,000–7,000 IU of vitamin D a day to get their 25-hydroxyvitamin D level over 50 ng/mL.
In the study presented at the American Heart Association conference, 25-hydroxyvitamin D blood levels were measured in 132,000 patients. Out of this large group, a small number (291 or 0.22%) had 25-hydroxyvitamin D levels over 100 ng/mL. This level exceeds what Life Extension (and most others) have long recommended.
As you'll read next, those whose 25-hydroxyvitamin D level exceeded 100 ng/mL had an atrial fibrillation incidence 2.5 times greater than those who were in the safe ranges (below 100 ng/mL).
Atrial Fibrillation and Excess Vitamin D Status
As the population ages, an increasing percentage develops an irregular rhythm in the upper chambers of the heart called atrial fibrillation. It is the most common type of heart arrhythmia and approximately 5% of persons over 65 years of age are expected to be diagnosed with it.2
The 132,000 subjects in the most recent study were defined by the following categories:
Definition of Vitamin D Status 25-Hydroxyvitamin D Levels
Low Less than 20 ng/mL
Low-normal Between 21–40 ng/mL
Normal Between 41–80 ng/mL
High-normal Between 81–100 ng/mL
Excess More than 100 ng/mL
In patients with low, low-normal, normal and high-normal levels of vitamin D, there was no increased risk of atrial fibrillation. Those with excess levels of vitamin D had 2.5 times greater risk of atrial fibrillation compared to those with normal blood levels.
The authors of this study recommended that people have their blood tested to ensure they are taking the proper dose of vitamin D. We at Life Extension long ago noted a wide dose-response variability with vitamin D and recommended 25-hydroxyvitamin D blood tests to ensure one is in the optimal range of between 50–80 ng/mL.
Most members are surprised that even taking 5,000 IU a day (or more) of supplemental vitamin D does not always get them above 50 ng/mL. In rare instances, however, doses of less than 5,000 IU result in blood levels greater than 100 ng/mL.
These real world findings confirm the importance of checking one's vitamin D blood status after initiating a daily dose significantly higher than 2,000 IU to establish how much vitamin D is individually needed to achieve optimal ranges (50–80 ng/mL) and not excess levels (over 100 ng/mL).
Symptoms, Concerns, and Causes of Atrial Fibrillation
Atrial fibrillation is usually accompanied by symptoms related to a rapid heart rate. Rapid and irregular heart rates may be perceived as palpitations or exercise intolerance. Sometimes atrial fibrillation symptoms produce angina and shortness of breath (in response to strenuous activity) or edema. An electrocardiogram test can usually diagnose atrial fibrillation.
Some common (and often preventable) causes of atrial fibrillation are:3
Hypertension (high blood pressure)
Coronary artery disease
Mitral stenosis (rheumatic heart disease or mitral valve prolapse)
Mitral regurgitation
Hypertrophic cardiomyopathy
Pericarditis
Previous heart surgery
Excessive alcohol consumption ("binge drinking")
Hyperthyroidism (excess thyroid hormone secretion)
The primary danger of atrial fibrillation is that it can create an abnormal blood clot to form in the left atrial chamber that breaks away and travels up the carotid artery causing a stroke.4 Patients with atrial fibrillation are usually prescribed anti-arrhythmic and anti-coagulant drugs to reduce this risk.
Ideally, the underlying cause of atrial fibrillation is identified and corrected so the problem goes away. Some cases of atrial fibrillation resolve themselves and require no treatment, or the patient takes steps to correct lifestyle choices that bring on atrial fibrillation.
We would expect anyone who may have developed atrial fibrillation in response to excess blood levels of 25-hydroxyvitamin D would be able to reverse the problem by lowering their vitamin D dose. Since vitamin D is fat-soluble, we would recommend that someone who had been taking 10,000 IU a day of vitamin D and whose blood levels of 25-hydroxyvitamin D are over 100 ng/mL should reduce their dose to no more than 2,000 IU a day for two-three months and then take another 25-hydroxyvitamin D blood test. If 25-hydroxyvitamin D levels drop below 50 ng/mL, they may want to initiate supplementation with an additional 2,000 to 5,000 IU a day and re-check their blood within the next three months.
It is interesting to note that in patients with excess amounts (greater than 100 ng/mL) of 25-hydroxyvitamin D in the study presented at the American Heart Association conference, a significant increase in hypothyroidism (sluggish thyroid function) was noted by the researchers. While hyperthyroidism (hyperactive thyroid function) is a well-known contributing factor in atrial fibrillation, in fact hypothyroidism is an underappreciated cause of heart disease, high cholesterol, and atrial fibrillation. The high prevalence of hypothyroidism in those with excess 25-hydroxyvitamin D represents an underappreciated risk factor for atrial fibrillation in this observational trial. In other words, it may have been hypothyroidism that caused the increased incidence of atrial fibrillation and not the vitamin D.5-7 We nonetheless continue to recommend that members keep 25-hydroxyvitamin D levels below 100 ng/mL.
Excess Vitamin D Intake Relatively Rare
Life Extension meticulously tracks its members' blood test results to look for trends that may indicate beneficial or detrimental events occurring in their bodies.
Before members started supplementing with higher doses of vitamin D, the majority (85%) had less than optimal levels, placing them at higher risk for contracting degenerative disease.
Since members have been taking higher vitamin D doses, this insufficiency has been largely corrected with relatively few results above 100 ng/mL, which can be easily reversed by reducing the daily dose.
The more common challenge is someone taking 5,000 IU (and higher) of vitamin D3 a day and still not being able to reach 50 ng/mL.
In as much as conventional medicine's upper limit reference range for 25-hydroxyvitamin D is 100 ng/mL, anyone who had their blood tested should have been able to adjust their vitamin D downward if their reading was above this level.
Do You Know What Your 25-hydroxyvitamin D Level Is?
If you've had your blood tested through Life Extension's convenient blood testing service and misplaced your results, just call us at 1-800-208-3444 and we will tell you what your past results have been.
If you are taking more than 2,000 IU of supplemental vitamin D and have never had your blood tested, we highly recommend it and are making the 25-hydroxyvitamin D test available at a special discount price.
The regular member discount price for the 25-hydroxyvitamin D blood test is $47. If you order it by De***ber 31, 2011, we'll give you the comprehensive CBC/Chemistry Panel at no extra charge.
The CBC/Chemistry Panel includes critical markers of health such as glucose, cholesterol, triglycerides, LDL, HDL, calcium, liver function, kidney function, and blood cell counts. The usual member price for the CBC/Chemistry Panel is $35, but you can get it free when you order a 25-hydroxyvitamin D blood test for only $47 by De***ber 31, 2011.
Based on the findings reported at the American Heart Association conference, we have further confirmation that the optimal ranges of 25-hydroxyvitamin D (50–80 ng/mL) we have recommended are safe and significantly effective in protecting against common age-related problems. There is now a basis (not yet published) to ensure that one does not exceed 100 ng/mL, which can be readily accomplished via low-cost blood testing.
What We Are Doing to Follow Up
Based on a review of members' blood test results and our in-house tracking systems, Life Extension has not seen a correlation between vitamin D levels in excess of 100 ng/mL and reported incidences of atrial fibrillation. We nonetheless urge members to maintain their 25-hydroxyvitamin D levels in the optimal range (50–80 ng/mL), as levels higher than this do not appear to confer additional benefit.
In as much as this was an unpublished study, Life Extension is in discussion with the authors who made this presentation at the American Heart Association meeting to verify what methodologies were used to establish a relationship between excess vitamin D and atrial fibrillation.
Unique Benefits of Using Life Extension's Blood Testing Service
Since 1983, Life Extension has recommended that members have comprehensive blood test panels at least once a year.
In 1996, we initiated a low-cost service whereby members could request their own blood tests, walk in for their blood draw (usually at their convenience), and be sent the results to show their doctor, or make lifestyle changes like altering their diet if results showed elevated glucose, triglycerides, LDL, etc.
A benefit that many may not realize is that our computer database readily enables us to go back and identify members whose results are not in proper ranges. So when a new finding appears that we can corroborate, such as where safe and optimal 25-hydroxyvitamin D levels should be, we can notify those who are above or below these ranges so they can take corrective actions.
No organization is more concerned about the health and longevity of its members than Life Extension. We have not heard of any other program that mines historical blood test data to notify individuals of new findings that can affect their health.
Life Extension retains copies of its clients' previous blood tests dating back to the year 2008 so we can quickly send them via e-mail or in paper form at no charge to you or your doctor. I think many of you have endured the bureaucracy that occurs whenever you have to interact with the medical establishment, as they erect barriers to the simplest patient request.
It is sometimes important to review previous blood test results in order for your doctor to identify trends that may indicate either a benign situation or one that requires medical attention. I recall sitting at lunch with a member who called his doctor and asked to obtain a copy of previous blood tests results. This member was told the cost would be $250 and results would not be produced right away. I told this member he could call Life Extension anytime and obtain previous blood test results at no charge with a turnaround time of less than two days.
To order any of Life Extension's Blood Test Panels, including the special offer of a free CBC/Chemistry Panel when ordering a 25-hydroxyvitamin D test for only $47, call 1-800-208-3444 (24 hours) or click here to order online.
If you have any questions about your vitamin D supplement program, feel free to call one of our health advisors at 1-800-226-2370 weekdays from 8 a.m. to 1 a.m. and weekends from 9 a.m. to 1 a.m. ET.
For longer life,
William Faloon
