Melatonin, a popular sleep aid supplement, has been linked to an increased risk for heart failure in a new study.
The research, which is scheduled to be presented at the meeting of the American Heart Association this weekend and has not been peer reviewed, suggests that chronic use of melatonin supplements could be a warning sign of heart failure among people with insomnia.
For the study, researchers looked at electronic health data for more than 130,000 people who had been diagnosed with insomnia and categorized them into groups based on whether or not they had been prescribed melatonin and for how long they'd taken the supplement.
Among those who had used melatonin, more than 65,000 had used it chronically, meaning for more than a year. And those who were taking melatonin for at least a year were almost twice as likely to experience heart failure in the next five years compared to those who did not use melatonin.
Those who took melatonin for at least a year had a 4.6% risk for heart failure within the next five years compared to 2.7% for those who did not use melatonin.
Melatonin is hormone that the body makes on its own naturally and is also found in some foods. It plays a major role in regulating your sleep and waking cycle, and supplements containing melatonin are a popular over-the-counter sleep aid, as TODAY.com explained previously.
While melatonin supplements are generally safe, they don't work for everyone and can come with side effects. And, as the new research suggests, using melatonin supplements frequently may be a sign that underlying health issues, like heart failure, are going untreated.
Those in the melatonin group were also more likely to be hospitalized for heart failure and to die from any cause within five years compared to those who were not taking melatonin.
“Melatonin supplements are widely thought of as a safe and ‘natural’ option to support better sleep, so it was striking to see such consistent and significant increases in serious health outcomes, even after balancing for many other risk factors,” Dr. Ekenedilichukwu Nnadi, lead author on the new research and an internal medicine resident at SUNY Downstate/Kings County Primary Care in New York City, said in a AHA press release.
Do Melatonin Supplements Cause Heart Failure?
The study does not prove that melatonin directly causes heart issues. Instead, the results suggest that the need to take melatonin frequently on a long-term basis may be a sign that underlying health issues are hidden or not being managed well.
“Insomnia can increase blood pressure, stress hormones and inflammation,” Nnadi told NBC News.
So chronic melatonin use may indicate that insomnia is severe enough to be causing additional health issues.
“While the study examined insomnia as a risk factor for developing heart failure, the reverse can also be true,” said Dr. Kanika P Mody, a heart failure and transplant specialist at Hackensack University Medical Center.
On the other hand, “Difficulty sleeping can be a symptom of existing heart failure," Mody explained in a press release. This can be due to disease-related anxiety, medication side effects, or breathing difficulties like shortness of breath when lying down that are common in heart failure patients, Mody added.
Another limitation of the research is that the data, which includes patients in multiple countries, only captures those who received a prescription for melatonin supplements. These supplements are also available over-the-counter in the U.S., so the research likely doesn't represent the full picture of melatonin use in the U.S.
And it's not clear how well the results would apply to those who use melatonin only for the occasional bout of sleep trouble.
For those who have a hard time getting consistent, good sleep, experts told TODAY.com previously that supplements generally shouldn't be your first option.
Melatonin can come in handy for people dealing with jet lag or night shift work, for example,, Naima Covassin, Ph.D., sleep disorder expert and assistant professor of cardiovascular medicine at the Mayo Clinic in Rochester, Minnesota, told TODAY.com recently.
But it shouldn’t be used to treat ongoing insomnia.
“There have been quite a few clinical trials, and most of them fail to find melatonin is better than a placebo,” Philip Richard Gehrman, Ph.D., an associate professor of clinical psychology at the Hospital of the University of Pennsylvania in Philadelphia, told TODAY.com previously.
“If it has any effect as a sleeping pill, they are very modest,” Gehrman said. Instead, evidence-based treatments for insomnia include cognitive-behavioral therapy, lifestyle changes and, sometimes, prescription medication.
And, in general, experts have told TODAY.com again and again that you should consult a doctor before adding a new supplement to your regimen — and to check in if it becomes a frequent habit. While they may seem harmless or "natural," supplements can have unintended consequences and may even interact with prescription medications.
“My concern is that insomnia may actually be masking signs and symptoms of early heart failure in some of these cases," Mody said. "So this research also highlights this importance of ruling out different causes of insomnia, particularly since the treatment market for insomnia aides is not strongly regulated.”
As the Council for Responsible Nutrition, the trade association for supplement companies, noted in a response to the new study, melatonin supplements should only be used occasionally. And those who are experiencing long-term sleep difficulties, you should talk to a medical professional before turning to melatonin.
