|
|||||||||||||||||||||||
 |
Melatonin |
|
|
|||||||||||||||||||||||||||
|
Melatonin
The hormone melatonin is now a popular therapy for jet-lag and disturbances of sleep. Claims are made for improved sex-life, longevity and even lowering of blood pressure. Melatonin is a hormone secreted by the pineal gland in the body. It is generally secreted at night, where in most people, levels are the greatest during the normal hours of sleep. The level of melatonin in the body rapidly increases in the late evening, peaks after midnight and decreases toward the morning. It promotes sleep by fixing abnormalities in sleep-wake cycles and by releasing a direct soporific effect, namely when taken during the day. However, melatonin supplements should be taken in the evening. Studies also suggest that Melatonin affects the immune response to cancer, possibly by creating effects on cytokines, which inhibit the growth of tumors by killing infected cells. How it Works in Your Body:
Cautions:
Consult your doctor if you: Over 55
years old:
Pregnancy:
Breastfeeding:
Infants and Children:
Storage:
Safe dosage:
Toxicity:
Side Effects: Sleep Tight with Melatonin Andy Coghlan New Scientist September 16,2000 People who are totally blind don't sleep too well at night. Their body clocks go awry because they can't sense any light, so they can't tell night from day. Now researchers have found a treatment: the anti-jet-lag hormone, melatonin. "Light is the major time cue in humans," says Debra Skene of the University of Surrey in Guildford. In sighted people with normal body clocks, levels of melatonin in the blood peak at around 4 am. In totally blind people, melatonin peaks at a different time each day. Their sleep suffers, so they often nap during the day to compensate for their disturbed nights. Skene wondered if the body clock of completely blind people could be reset with daily doses of melatonin. In an experiment on seven totally blind volunteers with severe sleep disruption, she found that the melatonin treatment gave most a better night's sleep, with fewer daytime naps. Later she found that the treatment only reset the clock if it was timed correctly in relation to the subject's own melatonin peak. "Melatonin can work, but we need to know the status of the clock before we begin treatment," she says. New Scientist, September 16, 2000
Winter Depression Linked With Melatonin Cycle People with seasonal affective disorder (SAD) instinctively shift their melatonin levels with the seasons, paralleling the hibernation patterns of mammals. This does not appear to be true for those who don't react to shorter days and longer nights with deepening depression. In patients who had SAD, the duration of melatonin secretion became longer in winter and shorter in summer, just as it occurs in other mammals. That could be controlling this panoply of changes that occurs in people when they get depressed in the winter. Seasonal affective disorder, or "winter depression," is a psychiatric disorder that strikes during winter months, when daylight hours are naturally shortened. The disorder in humans seems to mimic the behavior exhibited by hibernating animals, such as increased sleep and decreased activity. Melatonin, a hormone produced by the pineal gland in response to the darkness of nighttime, promotes sleep and helps regulate the body clock. Hibernation in mammals is triggered when the brain responds to the body's increase in melatonin production. Prior research suggests that people with seasonal affective disorder are unable to use artificial light to readjust their body clock, but remain susceptible to the seasonal rhythms of shorter daylight hours during wintertime. Healthy individuals were immune to shifts in the natural daylight, with their melatonin levels remaining stable throughout the seasons. However, those with winter depression had a moderate decrease in the length of time they produced melatonin during the summertime. The duration of active melatonin secretion was about 9 hours in the control group, whether in winter or summer. In the SAD group, active melatonin secretion was 9 hours in winter and 8.4 hours in summer. Archives of General Psychiatry December 2001;58:1108-1114
Lack of Daylight May Cause Insomnia Lack of exposure to sunlight might explain why sleep disturbances grow more common as people age, researchers in Japan suggest. In a study of 10 nursing home residents with insomnia, investigators found that increasing the residents' exposure to light improved their sleeping patterns. The dose of brightness also increased their production of the melatonin, a hormone believed to help regulate sleep. Some, but not all, research suggests melatonin production declines with age, and that melatonin supplements may combat insomnia. The researchers then exposed the patients to 4 hours of bright, artificial light at midday for 4 weeks -- roughly equal to the normal light exposure of the young control group. The investigators found that the extra light sent the elderly patients' melatonin production to a level similar to the young group's, and improved their sleep quality. Journal of Clinical Endocrinology and Metabolism January 2001;86:129-134
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||
