Monday, October 12, 2009


The pineal gland, located in the middle of the brain, receives light signals from our eyes, and has been called “the third eye” in times past. The pineal gland secretes a hormone called melatonin, synthesized from the amino acid tryptophan. Melatonin regulates the sleep-wake cycle, making you sleepy and lowering your body temperature as night comes on. Ever since the development of the electric light, we have been changing our sleep-wake cycle, our “chronobiology”, making sleep a problem for many people. Darkness increases melatonin production, while light, especially the blue part of the spectrum, inhibits its production. It’s not surprising that reading or working in bright lights until late at night makes it hard to fall asleep. Scientists at John Carroll University have developed blue-blocking glasses to wear in the evening to facilitate melatonin output. There are also blue-blocking nightlights, to assist you without disturbing your subsequent sleep.. (Blue-blocking glasses and lights are easily available on the internet.)

Insomnia As darkness stimulates melatonin outflow, it is wise to turn down the lights a few hours before bedtime, and/or wear blue-blocking glasses, which can be worn over reading glasses. Vigorous exercise at night blunts the outflow of melatonin, but exercise earlier in the day is known to improve sleep. According to Chinese traditional medicine, a ten minute slow walk in the dark can be helpful to promote sleep; they call it “a thousand steps at bedtime”. Over-the-counter melatonin tablets can be used on occasion for serious insomnia - start with dissolving ½ mg under the tongue about 30 minutes before going to bed. People differ in the dose they need to ensure sleep. Children with chronic sleep problems have also benefited from better sleep and better daytime behavior with occasional very low doses of melatonin. Talk to your pediatrician first!.

Jetlag Travelers across time zones find it useful to use melatonin at the new bedtime, and to expose themselves to bright light, a walk in the sun, in the morning. Long acting melatonin tablets may be the most helpful; start with a low dose such as 1.5 mg, and take more if needed.

Cancer Studies on lab animals suggest that giving melatonin reduces the incidence of breast cancer and slows its growth if the animal has been exposed to chemical carcinogens. Human breast cancer cells implanted into rats showed greater growth when the rats’ melatonin was suppressed. In humans, women who work night shifts – with increased exposure to light at night and corresponding melatonin suppression - show an increased incidence of breast cancer. The growth of prostate cancer cells is also suppressed by adding melatonin to lab cell cultures. Researchers at McMaster University in Toronto looked at multiple European studies on the use of melatonin in different solid cancers, and found that 10-40 mg/day was associated with increased survival rates and beneficial effects on sleep. Other anti-cancer treatments were used at the same time. Melatonin supplements are not regularly given to people with cancer in the US – if you want to try this approach, you should talk to your oncologist about adding melatonin to other treatments.

Sleeping Pill Withdrawal Many people are accustomed to taking a pill in the valium family (a so-called benzodiazepine) or Ambien/Lunesta for sleep on a regular basis. If you are taking a sleeping pill regularly, check with your doctor or pharmacist about its type, and its addictive potential. After a week or two of nightly use, it can be difficult to quit many prescription pills because of the resultant insomnia and nervousness. Withdrawal can cause serious problems and should be managed in gradual steps by a doctor who understands the problem. Some doctors find that melatonin tablets are helpful with the insomnia and anxiety of withdrawal from prescription sleeping pills. There are few good studies on whether melatonin is addictive, but it is believed to be safe in this regard.

Cautions with melatonin Melatonin tablets can make you drowsy, so avoid drinking alcohol after taking them, and avoid driving or operating heavy machinery. Do not take melatonin if you are pregnant or breast feeding. Do not give melatonin to children without the advice of your doctor. Melatonin supplements are associated with vivid dreams in some people.

The best approach to sleep is to do everything you can to let it occur naturally. Melatonin will be released from your pineal gland and give you restful sleep most of the time if you follow certain guidelines. Avoid caffeine and alcohol close to bedtime. Some people metabolize caffeine slowly and need to avoid it entirely or after breakfast. Exercise every day doing something you enjoy, but not too close to bedtime. Try using blue-blocking glasses in the hours before sleep, or listen to music with really dim lights. Many people sleep better after having an orgasm. If you need a sleeping pill occasionally, melatonin is one of the safer formulations, used at the lowest possible dose – such as ½ (0.5) mg. Avoid taking any sleeping pill every night; that way you should avoid addiction.

Sadja Greenwood, MD – past issues at Columns will resume in November.

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