Most people think of melatonin as primarily—or even exclusively—a sleep remedy. Melatonin, of course, is critical for healthy sleep. The body’s own melatonin production is essential to circadian rhythm regulation and the maintenance of daily sleep-wake cycles.
As a supplement, melatonin has grown tremendously popular, largely on the basis of its reputation as a sleep promoter. Indeed, melatonin is among the most used in the United States, according to the National Institutes of Health. Between 2007 and 2012, use of melatonin doubled among adults in the US, rising to slightly more than three million.
Here’s what’s fascinating: Some of the most broad and potent benefits of melatonin may lay outside the sleep realm. As this interesting Medscape article explains, scientists are learning more and more about the role melatonin can play in treating and preventing disease. At the same time, the effectiveness of melatonin’s most well-known use—sleep—remains something of an open question in the scientific community, even as millions of people take melatonin regularly for sleep.
Read on to learn what the latest science is telling us about how melatonin’s therapeutic reach may extend way beyond sleep, and how I think melatonin can be deployed most effectively in treating sleep problems.
Potential health benefits of melatonin beyond sleep
It’s almost getting easier to ask: what chronic diseases don’t melatonin play a role in? Recent years have seen a flurry of studies showing the protective and therapeutic benefits of melatonin in the fight against the most significant chronic diseases of our time—heart disease, cancer, dementia, diabetes. It’s role as an antioxidant and anti-inflammatory, as an anti-tumor agent, and its importance in maintaining circadian clock timing are some of the critical ways melatonin appears to have a far-reaching impact on health and disease, especially as we age.
Melatonin protects cardiovascular health. Melatonin has powerful antioxidant capabilities. Antioxidants work to protect cells and genes from damage, which can lead to dysfunction and the onset of disease. Antioxidant action reduces harmful inflammation and limits cellular and DNA damage from a process known as “oxidative stress,” which occurs when volatile chemicals known as “free radicals” proliferate in the body. Substances that function as antioxidants can neutralize the damaging effects of free radicals to hurt the integrity and proper functioning of cells and genes.
Melatonin’s antioxidant abilities are one mechanism by which this hormone may prevent and treat the damage of chronic and age-related diseases, from cardiovascular disease to cancer and neurodegenerative diseases like Alzheimer’s. (More on the melatonin-cancer connection in a minute.)
Recent research continues to demonstrate that melatonin may protect against and treat a range of cardiovascular conditions, including heart attack, stroke, high blood pressure and atherosclerosis (the accumulation of fat and cholesterol in the arteries).
Melatonin affects diabetes risk. Melatonin has been shown to have an influence over both blood sugar and insulin, key markers for metabolic health and drivers of metabolic disease, particularly type 2 diabetes. The science of melatonin’s role in diabetes risk and treatment is complicated and not yet well enough understood. There’s a robust body of research that indicates melatonin has a protective effect over metabolic health and can lower diabetes risk. The body’s own natural nighttime levels of melatonin have been linked to risk for developing diabetes. According to research, maintaining healthy nocturnal melatonin levels may cut one’s risk for diabetes in half, compared to people with low nighttime melatonin production. And other recent research has shown that supplemental melatonin may help to regulate blood sugar, keeping it from rising too high.
Still, other recent research has shown melatonin may complicate risk for diabetes by interfering with insulin, a hormone that helps cells access glucose from the bloodstream, thereby regulating blood sugar levels. Elevating levels of melatonin, in some people, may reduce the ability of specialized cells to release insulin, leading to higher blood sugar levels. These insulin-limiting effects of melatonin were shown to be particularly strong in people with a specific genetic variation that affects melatonin receptor cells. That same genetic variation has also been linked to a higher risk for type 2 diabetes.
Melatonin protects against age-related brain disease, including Alzheimer’s. Melatonin levels have been associated with Alzheimer’s disease for decades. People with Alzheimer’s tend to show lower levels of melatonin compared to age peers without the disease. And melatonin loss continues to escalate as the neurodegenerative disease progresses. A growing body of research shows melatonin has significant neuroprotective capabilities and may help to prevent Alzheimer’s in part by slowing or stopping the accumulation of damaging amyloid plaque and other harmful proteins in the brain, which many scientists think are behind the onset of the disease. Other research suggests that supplemental melatonin may help to reverse cognitive decline when Alzheimer’s disease is already present.
As it does throughout the body, melatonin functions as a powerful antioxidant in the brain.
Oxidative stress that damages brain cells is believed to be one significant contributing cause for age-related cognitive problems, and a factor in the development of neurodegenerative diseases including Alzheimer’s disease and others. Another likely reason for melatonin’s ability to protect brain health, according to scientific study? Its role in keeping circadian rhythms in sync.
Melatonin is an anticancer agent. Exciting research over the past several years has demonstrated the many ways that melatonin halts the onset and progression of several types of cancer. Studies have shown that melatonin can:
- Suppress cancer cell and tumor growth.
- Inhibit cancer metastasis.
- Help boost the effectiveness of cancer treatment, including for some treatment-resistant cancers.
- Reduce the severity of side effects from radiation and chemotherapy.
- Prevent cancer from developing in the first place.
Why is melatonin so effective in combating cancer at every phase of its development, from prevention to limiting progression and improving treatment? Scientists are still unpacking the complicated answer to that big question. Melatonin’s influence over circadian rhythms is one likely important factor. So is melatonin’s role in protecting cellular health, including limiting the effects of oxidative stress and promoting the orderly death of damaged and aged cells—a biological process known as “apoptosis.” When cells die in an orderly, systematic way, it eliminates damaged and dysfunctional cellular actors in the body, reducing the risk for cancerous cells to grow and replicate.
Next week we will discuss some more things to know about melatonin use.