Melatonin supplements may reduce the risk of developing age-related macular degeneration (AMD), the most common cause of severe vision loss in people over 50 years old.
Researchers discovered this link after analyzing electronic medical records collected between 2008 and 2023 from patients in the United States.
Scientists reviewed the records of more than 238,000 people over the age of 50 with no history of AMD, of whom about 121,000 reported taking melatonin. From this data, scientists estimated that people taking melatonin were 58% less likely to be diagnosed with AMD over the 15-year study period than those who did not take it.
The first group had to have reported to their doctor that they were taking melatonin at least four times over the 15-year period, with a minimum interval of three months between these reports. In the United States, melatonin is considered a dietary supplementit can therefore be purchased without a prescription.
Related: Melatonin consumption by children ‘extremely common,’ Colorado study finds
Although it revealed an interesting link, the study has some major caveats.
Notably, over-the-counter melatonin supplements can vary considerably in terms of purity and concentration of the ingredients included. Studies have suggested that melatonin gummies sold in the United States often contain much higher doses than those indicated – or more rarely, they contain no melatonin. This means that the actual dose of melatonin people were taking in this study is unknown.
But despite this, the research, published June 6 in the journal JAMA Ophthalmologysuggests that melatonin could potentially help prevent a very common form of vision loss.
“I think the potential for this inexpensive, widely available supplement to reduce the risk of AMD is potentially exciting,” Dr. Glenn Yiu, professor of ophthalmology at the University of California, Davis Health, who was not involved in the research, told Live Science in an email. Keeping the caveats of the current study in mind, “I will be curious to see if other, more rigorous studies confirm these interesting results,” he added.
Melatonin and vision loss
In the human eye, the retina contains light-sensitive cells that send messages to the brain. The macula, the central part of the retina, allows us to see objects that are directly in front of us. AMD affects vision because it gradually damages the macula. People with AMD may experience blurred or distorted vision in the center of their visual field, but the disease does not cause total blindness.
There are two main types of AMD: dry AMD and wet AMD. Dry AMD is the mildest form of the disease which occurs in 80% of cases and is caused by the progressive breakdown of light-sensitive cells in the macula. Wet AMD also involves abnormal growth of blood vessels under the retina, and these blood vessels may start leaking fluiddamaging cells and leading to severe vision loss. Between 10% and 15% of patients with dry AMD will develop wet AMD.
In addition to looking at people without AMD who later developed the disease, the researchers wanted to see if taking melatonin could prevent the progression from dry to wet. So in a second analysis, the team surveyed the medical records of about 128,000 patients diagnosed with dry AMD, of whom about 66,000 were taking melatonin and 62,000 were not taking melatonin. They found that those who took melatonin were 56% less likely to develop wet AMD over a 15-year period than those who did not take it.
In both analyses, similar trends were observed in patients in their 50s, 60s, and 70s, the team found.
Because the study only looked at associations between melatonin and AMD, it cannot prove that melatonin directly opposes the biological processes that cause the disease. The authors also acknowledge that people’s lifestyle habits and access to health care may have influenced their risk of AMD, rather than melatonin, but they did not take these factors into account.
The results reaffirm previous research on rodents And humans which suggest melatonin, which is often prescribed for treat sleep disorders such as insomnia, could target some of the key biological processes that cause AMD. This includes an increase inflammation and oxidative stress, or a buildup of free radicals in the body that can damage cells. This is important given that there is currently no cure for AMD, and preventive interventions are often limited to lifestyle changessuch as maintaining a healthy diet and quitting smoking.
“The potential benefits of new treatments to prevent AMD are enormous from a public health perspective,” David REINsenior public health researcher at the National Opinion Research Center (NORC) at the University of Chicago, who was not involved in the research, told Live Science in an email.
Gold standard clinical trials are still needed to determine whether melatonin actually prevents the development or progression of AMD. These trials would compare people who take melatonin to those who don’t, and the doses and quality of the supplements would be carefully monitored.
It is important that these trials are completed before doctors make recommendations regarding patients using melatonin for eye health, Dr. Rajendra Aptéprofessor of ophthalmology and visual sciences at Washington University in St. Louis, who was not involved in the research, told Live Science in an email.
This article is for informational purposes only and is not intended to offer medical advice.
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