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.
Manufacturers win with vitamin D
For product manufacturers, vitamin D is quite inexpensive to source. To have 1,000 IU in your product would cost about 0.045 cents, according to supplier Dan Murray of Xsto Solutions.
“I think we should fortify at 1,000 IUs per serving if we want to have an ‘impact’-type dose,” said Murray. “More is possible if we are talking a supplement, but for food we should stay a little low. It would not be unreasonable for a food to have 400 IUs and hold itself out as being ‘high’ in vitamin D with 100% of the RDA.”
Murray offered what he called “pantry” research and found the additional price of formulating with higher vitamin D levels as follows:
Nutri-grain Bars—8 bars/8 servings per box so adding 8,000 IUs would cost 0.36 cents per box. 400 IUs would cost 0.14 cents per box.
Cheerios—9 servings per box so adding 9,000 IUs would cost 0.41 cents per box. 400 IUs per serving would cost 0.164 cents per box.
Store brand mac & cheese—2.5 servings per box would add 2,500 IUs and cost 0.11 cents per box. 400 IUs per serving would cost 0.044 cents.
Nestle Hot Cocoa Mix—10 packs/servings would cost 0.45 cents per box. 400 IUs would cost 0.18 cents per box.
- Smuckers Jam—28 servings per squeeze bottle would cost 1.26 cents per squeeze bottle. 400 IUs would cost 0.50 cents per bottle. With regard to percentage of revenue, the cost on this product is $2.85 so the cost to formulate a 1,000 IUs per serving would amount to 0.44 % of the retail cost. Smuckers doesn’t receive revenue based on the retail cost but assuming they get 40-50% of retail, the cost is still about or less than 1% of product cost.