Known as the “sleep hormone” melatonin plays a big role when it comes to brain health. Melatonin deficiency is linked to Alzheimer’s disease and Parkinson’s disease. In addition, melatonin appears to lower risk of strokes and protecting the brain after traumatic injury.
What is Melatonin?
Melatonin is a hormone produced in the pineal gland, a pea-size gland that sits in the center of the brain. Melatonin regulates our sleep. It is produced at night when the sun goes down and its production is shut off in the morning as the sun comes up. Melatonin enables the pineal gland to regulate our circadian rhythms or internal clock that regulates many biologic processes.
Melatonin is also a very powerful antioxidant, and it’s through its antioxidant capabilities that is protects the brain from oxidative stress that contributes to neurodegenerative diseases like Alzheimer’s and Parkinson’s, and the oxidative stress that results from strokes and traumatic brain injury.
Melatonin and Oxidative Stress
It is unique among the many other antioxidants in that melatonin crosses the blood-brain barrier (makes sense since it is produced in the brain). This means it is one of the few antioxidants that protect the brain from oxidative stress.
Melatonin production declines during our middle years weakening the brain’s natural defense against oxidative stress. Individuals over age 80 have melatonin levels half that of young, healthy individuals. Levels in Alzheimer’s patients are one-fifth that of young, healthy individuals. Melatonin protects the brain from two abnormal proteins produced in individuals with Alzheimer’s – beta amyloid and tau proteins that lead to brain cell death.
Higher melatonin levels are associated with lower risk of strokes, plus melatonin minimizes the damage caused by stroke secondary to its antioxidant properties. Melatonin can also lower LDL cholesterol and blood pressure.
Melatonin improves brain plasticity – the ability for brain cells (neurons) to assume the function of the damaged brain cells following a stroke.
In patients with mild cognitive impairment melatonin supplementation has been shown to improve cognitive function.
Symptoms of Melatonin Deficiency
Symptoms of low melatonin include insomnia, restlessness, and sundowning. Sundowning is a disturbance of the circadian rhythm in which the body tends to rev up in the evening rather than calm down. This leads to agitation, restlessness, and in some cases confusion. Sundowning is common in individuals suffering from Alzheimer’s disease and other forms of dementia.
Some prescription drugs used for anxiety and insomnia actually lead to melatonin deficiency and include Xanax, Valium, and Ativan. These drugs are called benzodiazepines. Furthermore, individuals who use benzodiazepines are at a 50% greater risk of developing dementia later in life as reported in an study published in the British Medical Journal.
In the United States melatonin is available over the counter as a nutritional supplement. It most commonly comes in 1 mg and 3 mg doses, though doses as low as 500 mcgs (0.5 mg) can be found. In Europe melatonin is a prescription drug.
Melatonin supplementation is most beneficial for individuals over age 45 with sleep disturbances. Most individuals under age 45 make enough melatonin, but they may benefit from it for treating jet lag on a short term basis.
For treating insomnia the dose can vary greatly from one individual to another. It’s generally wise to start with 0.5 mg to 1 mg at night and increase by 0.5 mg to 1 mg every two to three nights until sleep is improved. Most people need no more than 3 mg. Too high a dose can cause a “hangover” effect or groggy feeling the next morning. Some individuals report more vivid dreams, too.