For decades, doctors have been looking for a surefire way to prevent atrial fibrillation, an arrhythmia that can be fatal. Now, a new, high-quality study has ruled out two possible competitors: vitamin D and fish oil supplements.
The study, called VITAL-Rhythm, was the focus of a recent virtual conference organized by the American Heart Association (AHA), the nation’s largest professional body of doctors who focus on the heart and the cardiovascular system.
“Atrial fibrillation is a very common condition and difficult to treat,” said Dr. Christine Albert, lead author of the study and chair of the cardiology department at the Smidt Heart Institute in Cedars-Sinai. “There are an estimated 33 million people in the world with atrial fibrillation.”
Doctors said it was a relief to see such high quality evidence because they could focus on new areas of research and not be able to prescribe unnecessary pills for their patients.
Previous studies have identified a possible association between these supplements and rates of atrial fibrillation, but it was not clear whether these differences were caused by the supplements themselves or some other inexplicable factor, such as:
Albert and her research team started an extensive study of 25,000 volunteers who were randomly selected to receive vitamin D, fish oil, or a placebo pill.
Dr. Erin Michos, director of womens cardiovascular health and assistant director of preventive cardiology at the Ciccarone Center for the Prevention of Cardiovascular Disease at Johns Hopkins University Medical Center, said the study was commended at this year’s American Heart Association conference for being one high quality study in which different volunteers participated. This means that the results are applicable regardless of race or gender.
“They looked at vitamin D at 2000 IU per day versus placebo while also examining 840 milligrams of marine omega-3s per day versus placebo. This was a randomized clinical trial and it was blinded so participants didn’t know if they were taking a dietary supplement or a placebo, “Michos said.
In the past, large studies have fallen victim to underrepresentation and diversity, making it difficult for clinicians to apply these studies to their actual patient population. This study, meanwhile, represented a larger population of African Americans and women.
An undated photo of fish oil supplements.
Michos said the importance of having strong African American representation in this process was critical. Many have lower levels of vitamin D in their blood due to the darker skin pigmentation, resulting in poor absorption of UVB light, which is necessary for active vitamin D to be made and to reap its benefits.
“I applaud the study’s investigators for their diversity efforts in this study,” Michos said. “Twenty percent black enrollment means they were over-represented relative to their proportion of the US population.”
In addition, Michos said that women are often underrepresented in cardiovascular studies, which usually limits doctors’ understanding of whether a drug or treatment works as well in women as it does in men.
“However, this was not the case in the VITAL-Rhythm study,” said Michos. “51% women took part in the VITAL study.”
In recent years, research has shown a behavioral change in some Americans towards an increase in supplement use: an estimated $ 120 billion industry.
However, researchers say the real health benefits of diet supplements are often overstated.
“The vast majority of dietary supplements seem to be of no use. Again, more is not better if you are not deficient in nutrients. Some high-dose supplements can even cause harm,” Michos said.
There is growing evidence that dietary supplements fail to prevent primary or recurrent cardiovascular disease. Another debut study at the AHA, the OMEMI study, showed no benefit in adding marine polyunsaturated n-3 fatty acids to prevent a second heart attack.
However, what has been shown repeatedly is the benefits of diet and exercise in preventing, or sometimes even reversing, conditions such as atrial fibrillation.
“We tend to look for the magic nutrient so we don’t have to eat good food,” Albert said.
Albert said the most effective prevention is to maintain a healthy weight, reduce alcohol consumption to 1-2 drinks a day, and maintain healthy blood pressure.
Michos agreed, advising that a healthy lifestyle and eating habits can prevent not only atrial fibrillation but heart disease as a whole.
“Moderate exercise, a healthy diet, and maintaining a normal weight can all reduce the risk of atrial fibrillation. I think people would be better served if they saved their money on failed supplements and their time and money instead for activities that promote a healthy lifestyle, “she said.
Lily Nedda Dastmalchi, DO, MA, is an intern in internal medicine at George Washington University and a member of the ABC News Medical Unit.