A few years ago, pediatrician Dr. Judith Owens noticed a disturbing pattern. A professor of neurology at Harvard Medical School at Boston Children's Hospital, many of her patients are children who have trouble sleeping. “I’ve been in practice for 40 years,” she says. “There has been a dramatic change in the number of patients I see, especially in the sleep clinic, who are now taking melatonin.” Now she rarely sees a sleepless child whose parents have not at least tried to give him the hormone.
It's not just children. Between 1999 and 2018, the number of adults taking melatonin, which is sold over-the-counter as a supplement in the United States, increased. more than five times. It is often marketed as a natural sleep aid—almost like a vitamin. However, because it is classified as a supplement and not a drug, the US Food and Drug Administration does not require (and does not) evaluate these claims. What's more, “The American Academy of Sleep Medicine does not recommend melatonin for insomnia,” says Marie-Pierre St. Onge, director of the Center of Excellence in Sleep and Circadian Rhythm Research at Columbia University.
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The effects of taking the hormone daily over a long period of time have not been well studied. In November, preliminary unpublished results were presented at a meeting of the American Heart Association. found a connection in adults, there is a gap between taking melatonin for more than a year and heart failure. While this study may be less informative about melatonin than it is about the link between heart disease and insomnia, it highlights the fact that relatively little is known about using melatonin in the way that a growing number of people are using it.
This gap worries many sleep doctors, including Owens. “It’s a hormone that has a lot of powerful effects,” she says.
What does melatonin do?
In the evening, your body begins to produce melatonin, which is produced primarily by the pineal gland. Melatonin levels peak in the early morning and decline after sunrise. This hormone is believed to give the body a sense of the length of the night and help synchronize biological processes with the sun.
However, when melatonin floats around, it affects more than just sleep. Several decades ago, scientists were surprised to discover that this adjusts the immune systemstrengthening and reducing various forms of inflammation. Melatonin deficiency leads to increased fat accumulation in the liver of mice. There is evidence that tissues other than the pineal gland including bone marrowproduce their own melatonin and a list of cell types with receptors that allow them to sense melatonin turns out to be huge. Hormone also appears to help control cell deathSo scientists are curious what role it might play in aging in general.
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Careful studies of melatonin and its metabolites in the blood and urine of people have shown that there are a number of diseases in which its levels are impairedincluding depression, schizophrenia, bipolar disorder, type 2 diabetes and some types of cancer. Some people with Alzheimer's disease may have a very small daily melatonin cyclewhich may contribute to the sleep problems that are a feature of the neurodegenerative disorder.
Taking melatonin as recommended by a doctor may be helpful for people in such situations. Research has also shown that blind people whose natural melatonin cycles are disruptedleaving them with constant jet lag may benefit from supplements. Children with autism can sometimes benefit from melatonin, Owens said. It is also being studied as a potential treatment for heart attacks, according to Dr. Tom Scammell, a professor of neurology at Harvard Medical School and a physician at Beth Israel Deaconess Medical Center.
How People Actually Use Melatonin
There's a big gap between how researchers and doctors think about melatonin and how many people use it. To try to trace the connection between long-term melatonin use and other diseases, some researchers have turned to electronic medical records.
November 3, excerpt from the American Heart Association The meeting described unpublished research using this type of data. It included some startling numbers: over five years, adults who were prescribed melatonin and took it for a year or more had a 90% greater risk of heart attack than people with similar health conditions who did not take melatonin.
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“Melatonin supplements may not be as benign as is commonly believed. If our study is confirmed, it could impact how physicians counsel patients about sleep medications,” said Dr. Ekenedilichukwu Nnadi, lead author of the study and chief resident in the department of internal medicine at SUNY Downstate/Kings County Primary Care, in a statement. statement.
However, melatonin is not necessarily the cause of the heart failure seen in this study. In fact, Scammell notes, insomnia and heart disease often co-occur: 50% of people with heart failure have insomnia, compared with 15% in the general population.
So people who suffer from insomnia and who are given melatonin by doctors in an attempt to cope with it may already be on the path to developing more serious heart problems.
“It is possible that the poor sleep triggered by melatonin use was an early sign of heart problems,” says Scammell.
More data needed
However, the study is an attempt to answer the larger question of how long-term melatonin use affects the body.
Does taking melatonin as a supplement affect the body's ability to produce melatonin naturally? “It's still an open question,” Owens says. But as a pediatrician, she worries that children who take melatonin regularly for months or even years may suffer long-term effects that may only become clear later.
“Melatonin affects the immune system, bone growth, the reproductive system. It's always been a big concern whether it affects sexual development,” she says. While short-term studies have found no immediate effect, there are no studies looking at the long term, she continues.
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Dr. Marcel Smits, a neurologist at Gelderse Valley Hospital in the Netherlands, is studying the use of melatonin in children with ADHD and other diagnoses. He and his colleagues found that after an average of 3.7 years, these children who took the medication regularly at doses determined by their doctors showed no side effects.
But in these cases, it is necessary to accurately calculate the dosage and monitor patients, he says. In adults and children, taking too much melatonin can disrupt the body's circadian rhythm, potentially impairing sleep or causing other effects. What's more, some people break down melatonin more slowly than others, and even a moderate dose may stay in their system longer than desired, he says.
In the UK, melatonin is only available by prescription and is intended for use for short periods of time under medical supervision. The fact that melatonin is readily available in the U.S. may contribute to misuse, St. Onge says: “When it's sold over the counter, people feel like it can't hurt. If it can't hurt, a lot may be better than a little.”
“This is something we need to understand more about and really appreciate what it means to take melatonin long-term,” she continues.
If you're having trouble sleeping, your best bet, St. Onge and Owens agree, is to try to change your bedtime behavior. Cognitive behavioral therapy for insomnia or CBT-Iis the gold standard treatment for insomnia in both children and adults. Research shows that this modification, which involves a series of steps designed to prepare you for better sleep, has longer-lasting and better effects than any sleeping pill.
There is something to sleep on.
