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Melatonin

Melatonin is a hormone produced by the brain that plays a role in the body’s natural sleep-wake cycle. It can also be produced by the amino acid tryptophan. Concentrations of melatonin increase in the body as night approaches, with concentrations being 10 times higher at night versus the day. As night approaches, signals are sent to the brain to produce more melatonin, and this can cause the onset of sleepiness. Therefore, melatonin is often promoted as a sleep aid.

 

Claimed Health Benefits

  • Aids in sleep

  • Helps with jet-lag

  • Slows the aging process

  • Increases sex hormone concentrations

  • Acts as an antioxidant

 

Food Source

There are some foods that contain small amounts of melatonin. Oats, sweet corn, and rice are the best sources of melatonin. However, to get the same amount of melatonin that is found in a supplement pill, you would need to eat about 20 bowls of oats. Ginger, tomatoes, bananas, and barley also contain small amounts of melatonin.

 

Dosage

Typically, 1-3 mg of melatonin is prescribed 2 hours before bedtime, although other reports say that between 1-10 mg are effective.

 

Evidence for Health Benefits

Studies have shown that supplementing with melatonin induces sleep in several groups of individuals such as jet-lagged travelers, the elderly, military pilots, those suffering from delayed sleep disorder, and night-shift workers.

Another study has shown that melatonin is helpful for blind individuals who have disturbances in the natural sleep-wake cycle.

Melatonin has also been shown to act as an antioxidant in the body by decreasing oxidative damage to DNA, lipid membranes, and proteins of cells.

 

Cautions

Taking high doses of melatonin (~50 mg) may interfere with female fertility, causing irregular menstruation. Such levels should only be taken under the supervision of a doctor.

Side effects could include grogginess, drowsiness, sleepwalking, and disorientation.

Melatonin may increase severity of depression.
Individuals at risk of cardiovascular disease should not take melatonin without a doctor’s permission, as it can cause high blood pressure.

The National Institutes of Health has issued warnings of the severe side effects of melatonin supplementation including female infertility, decreased male sex drive, interaction with hormone replacement therapy, damage to the retina of the eye, and hypothermia.

It is recommended that those who are pregnant, breast-feeding, those suffering from depression or schizophrenia, and those with autoimmune diseases such as lupus should avoid melatonin until more long-term studies are completed.

 

References

1. Consumerlab.com (2003) Independent tests of herbal, vitamin, and mineral supplements http://www.consumerlab.com/results/melatonin.asp Accessed December 15, 2003.

2. SupplementWatch, Inc. (2002) Supplement Decisions Made Easy. http://www.supplementwatch.com/supatoz/supplement.asp?supplementId=199 Accessed December 15, 2003.

3. Healthnotes, Inc. (2003) Helping People Lead Healthier Lives. http://www.healthwell.com/healthnotes/healthnotes.cfm?ContentID=2883002 Accessed December 15, 2003.