Is Vitamin D Good for the Heart, Longevity, and Atrial Fibrillation?

Get Your Life Back in Rhythm

Is Vitamin D Good for the Heart, Longevity, and Atrial Fibrillation? My answer to is vitamin D good for the heart, longevity, and atrial fibrillation is changing based on the most recent studies. While low vitamin D levels are definitely associated with heart attacks, heart failure, atrial fibrillation, longevity, cancer, infections, premature death, dementia, etc. it is becoming increasingly clear that taking a vitamin D supplement may not decrease the risk of any of these bad things happening. So what do the latest studies say and should we still take a vitamin D supplement for low vitamin D levels? Read on to learn more. The Vital Trial The main findings of the Vital Trial were published in 2019. This was a randomized controlled trial (RCT) which is the highest quality study you can do. It was also published in the most prestigious medical journal, The New England Journal of Medicine. The Vital Trial enrolled 12,987 patients and through a complex randomization process specifically evaluated whether taking 2,000 IU of vitamin D or a placebo could prevent cancer, heart attacks, strokes, or a cardiac death. To get into the Vital Trial you had to be age 50 or older if male and 55 or older if female. The reason why they picked an older age group is that at these ages the risk of heart disease and cancer start really going up. As you might suspect, for those randomized to 2,000 IU of vitamin D, their 25-hydroxyvitamin D levels did somewhat increase from 29.8 ng/mL to 41.8 ng/mL. For those not familiar with 25-hydroxyvitamin D levels, normal is 30 to 100 ng/mL. With this in mind, you can see that the people studied didn't really have that low of vitamin D levels, to begin with. Regardless, researchers then following these 12,987 patients for the next 5.3 years to see if this slight increase in vitamin D levels could prevent cancer, heart attacks, strokes, or a cardiac death. Sadly, 2,000 IU of vitamin D daily did none of the above. There was no statistical difference in the number of cancers, heart attacks, strokes, or cardiac deaths between the vitamin D supplement group and the placebo group. And a just-published sub-study from the Vital Trial also showed that a 2,000 IU vitamin D supplement did nothing to prevent atrial fibrillation. Surprisingly, even in the group with super low vitamin D levels (less than 20 ng/mL) a daily vitamin D supplement still didn't prevent atrial fibrillation. Vital Trial and Atrial Fibrillation Risk So what did all these millions of dollars spent on this study really teach us? Well, we learned that even though low vitamin D levels have been shown to be associated with an increased risk of atrial fibrillation, a supplement doesn't seem to fix anything. Of course, one could argue that only increasing 25-hydroxyvitamin D levels from 29.8 to 41.8 ng/mL is simply not enough to make a difference in arrhythmias. And it's certainly possible that many episodes of atrial fibrillation during the 5 plus years of follow-up were probably missed as these people were not continuously monitored for arrhythmias. And given that the mean age of this study was 67, one could also argue that the results may not apply to younger patients. Our 2011 Vitamin D Atrial Fibrillation Study When trying to assess the results of the atrial fibrillation Vital Trial, I have to put in a plug for our 2011 vitamin D atrial fibrillation study. In this study, we looked at the impact of vitamin D on 132,000 patients within the Intermountain Healthcare system in Utah and Idaho. In our study, the average age was 52 and 71% of the patients were women (as opposed to the 50/50 male-female mix in the Vital Trial). One finding of our study was that there was a trend toward low vitamin D levels being associated with atrial fibrillation (14% increased risk that didn't quite reach statistical significance). However, the key finding of our study was that over-supplementation with vitamin D,