What is in this article?:
- Vitamin Dâ€”can you take too much?
- Manufacturers win with vitamin D
Here's how product developers of supplements, foods and beverages can take advantage of new vitamin D research—whatever it might say.
America’s favorite letter vitamin, the sunshine vitamin D, is continuing to make news in the research front. Only this time, the TV broadcasters alerted, “Too much vitamin D can cause heart problems.”
The study in question was a presentation at a meeting of the American Heart Association on November 16. In it, researchers followed 132,000 adult Utahns (average age 52 years old) for 20 months.
Earlier this year, the Institutes of Medicine came out with revised vitamin D recommendations that declared blood levels below 20 ng/ml as too low.
Most vitamin D researchers, as well as progressive physicians, said that number is far too conservative, with the minimum being at least 30 ng/ml, with optimal levels ranging from 40-80 ng/ml.
In the study, those with 25-hydroxyvitamin D levels between 61 and 80 ng/ml had a 52 percent reduced risk of diabetes compared to those with deficient levels, described as below 20 ng/ml. Those with 25-hydroxyvitamin D levels between 81 and 100 ng/ml had a 36 percent reduction in hypertension incidence compared to the deficient group. The higher-D group also had significantly lower risk of heart failure, coronary artery disease, kidney failure, depression and prior stroke.
So shouldn’t the headlines have said something decidedly different?
Turns out there was a small subset of 291 people of the 132,000 who had 25-hydroxyvitamin D levels above 100 ng/ml. These people had an increased occurrence of atrial fibrillation – irregular heartbeats – compared to lower vitamin D levels. The rate was 3.8 percent of this tiny subset with high vitamin D levels who had atrial fibrillation, compared to 1.4 percent of those with normal vitamin D levels.
So if you are in the 0.22 percent of people with wildly high vitamin D levels, you may want to back off on your supplementation.
For the 99.78 percent of other people on the planet, you are likely not taking enough vitamin D. Because vitamin D intake does not necessarily correlate to blood 25-hydroxyvitamin D levels, getting a blood test from your doctor can inform you on your current blood levels of vitamin D. Then, after supplementing with more than you currently are, get a re-rest in six months to see what your new levels are. If you can get your levels higher than 60 ng/ml, according to this study, you can expect reduced risk of diabetes, reduced incidence of heart failure, coronary artery disease, kidney failure, depression and repeat strokes in patients who have already suffered a stroke.
Meanwhile, in another vitamin D study just published in the American Journal of Cardiology, researchers following 10,899 patients (mean age 58, 71 percent women) found mean vitamin D levels of 24.1 ng/ml. The researchers found that more than 70 percent were deficient—what they defined as 25-hydroxyvitamin D levels lower than 30 ng/ml, a full 50 percent higher than the IOM recommendation.
These researchers found vitamin D deficiency led to significantly higher incidence of cardiovascular disease and all causes of death.