Melatonin is a hormone naturally produced in the brain. It is manufactured in the pineal gland and regulates the body's circadian rhythm, or internal clock. It is circadian rhythm that keeps the body on its 24-hour sleep and wake cycle. Melatonin also helps regulate other hormones in the body, including the female reproductive hormones that signal the beginning, end and duration of the menstrual cycle. Melatonin is also synthesized in lab and sold as a dietary supplement, being used as a sleep aid and to combat jet lag. Some side effects are associated with its use.
Melatonin and the Brain
The pineal gland is located deep within the third ventricle of the brain and is often referred to as the "third eye." It is shaped like a small pine cone and functions to convert the essential amino acid tryptophan into serotonin, which is then converted into melatonin. Receptors in the retina send light signals to the pineal gland. The pineal gland then produces more or less melatonin depending on the amount of light impulses being sent from the retina. More melatonin is produced in the darker hours of nighttime, and less in the daytime.
Uses
Melatonin dietary supplements are most often used to treat insomnia. Night shift workers in particular are often plagued with insomnia due to disrupted circadian rhythm. Melatonin is also used to combat jet lag, which also causes a disruption in circadian rhythm; it can be very effective when someone has to cross five or more time zones. People who are blind and those with low levels of melatonin, including senior citizens, children with ADHD and schizophrenics, often find melatonin beneficial in improving sleep patterns. More studies are needed, but MayoClinic.com reports melatonin may provide some benefit in fighting macular degeneration, prostate cancer and breast cancer.
Side Effects
MedlinePlus, an online resource of the National Institutes of Health, lists melatonin as likely safe for doses up to 5 mg when taken for short periods of time. Melatonin can produce extremely vivid dreams and nightmares. It can cause daytime drowsiness if taken in large doses and increase the symptoms of depression. There is conflicting evidence, but there may be an increased risk of developing seizures. Melatonin causes headaches, mood changes, sleepwalking, dizziness and confusion in some. Heart effects include decreased blood pressure, increased cholesterol levels and irregular heartbeat and it may cause increased blood sugar levels in diabetics. Other side effects include gynecomastia in men, nausea, vomiting and decreased libido.
Precautions
Consult your doctor about the need for melatonin, making sure to discuss all other medications and supplements you are taking. It should only be used under medical supervision in pre-adolescent children. Women who are pregnant or breast-feeding should not take melatonin. Do not take melatonin if you are taking blood pressure medications, antidepressants, nonsteroidal anti-inflammatory drugs, diabetes medications or anti-coagulants. Tobacco, caffeine and alcohol can lower melatonin levels, so avoid them if taking melatonin supplements.
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