Melatonin is a hormone in the same category as estrogen and testosterone and should not automatically be used as liberally as its current availability suggests. It is manufactured from tryptophan by the pineal gland in the brain and secreted in small amounts. Melatonin plays an important role in the sleep cycle, the trigger for melatonin secretion being decreased light exposure: as sunlight exposure decreases, melatonin secretion begins. Melatonin is sometimes called the "Dracula of hormones" – it only comes out in the dark.
Melatonin influences the immune system and evidence is accumulating that it is a regulator of sex hormone production and useful in several male and female conditions. Melatonin deficiencies have been seen in patients with in cancer, heart disease, ulcers, Alzheimer's, and SIDS, although some of these correlations don't appear to be particularly strong.
Low melatonin levels are found in those with Seasonal Affective Disorder, and those with bipolar disorder have low melatonin levels at night and high levels in the morning – opposite to what it should be. The anxiety of PMS, or anxiety in general, can be associated with low melatonin levels. Schizophrenics also tend to have low melatonin levels, perhaps caused by their medications. Low melatonin levels are also found in those with breast or prostate cancer, decreased blood flow in the heart, Alzheimers disease, and other dementias.
The following can help boost melatonin levels:
Increase consumption of sources of melatonin's precursor, tryptophan. For example, oats, rice, barley, pumpkin seeds, almonds, peanuts, soybean, spirulina seaweed, brewers yeast, sweetcorn, tomatoes, ginger, bananas, milk, yoghurt, cottage cheese, turkey, chicken, chicken liver.
It seems as though melatonin encourages some level of restorative function during sleep. There is moderately good evidence from controlled experiments that melatonin will increase life expectancy in some cancer patients.
For more information, see the following books:
Melatonin: Nature's Sleeping Pill, by Ray Sahelian
Melatonin, by Russel Reiter, Ph.D. and Jo Robinson
A history of light, anxious, restless sleep is often evidence of low melatonin levels.
Melatonin can exhibit strong effects on the reproductive system, and the activity of the female hormones estrogen and progesterone is closely tied with its regulation of the sleep-wake cycle. Abnormal biological rhythms and sleep-wake cycle disturbances are often a primary feature of periodic depression, another common characteristic of PMS. Melatonin imbalances have been specifically linked to PMS.
A study reported finding that women with PMS had an earlier decline in melatonin secretion, resulting in a shorter overall secretion time. "The data demonstrate that women with premenstrual syndrome have chronobiological abnormalities of melatonin secretion... The fact that these patients respond to treatments that affect circadian physiology, such as sleep deprivation and phototherapy, suggests that circadian abnormalities may contribute to the pathogenesis of premenstrual syndrome." [Arch Gen Psychiatr 1990;47(12): pp.1139-46]
Melatonin levels were found to be generally lower in patients with Night Eating Syndrome.
One of melatonin's roles is the reduction of estrogen production in the body, and probably also reduction of the number of estrogen receptors. Studies have shown that the protective, estrogen-reducing effects of melatonin are significantly reduced by excessive exposure to light (including late night TV viewing) and probably electromagnetic fields, chemical pollutants such as pesticides and fungicides, and many commonly prescribed drugs, such as beta blockers for heart disease, high blood pressure and headaches.
There is evidence that a lack of melatonin could significantly increase the risk of developing gallbladder stones. Melatonin inhibits cholesterol secretion from the gallbladder, helps convert cholesterol to bile, and as an antioxidant can reduce oxidative stress on the gallbladder. [Digestive Diseases and Sciences. 2008;53(10):pp.2592-603]
A 1998 study found an extraordinarily strong correlation between melatonin level and endometrial cancer. Women were selected who appeared that they might have endometrial cancer. The women who in fact did not have endometrial cancer had an average melatonin level of 33. The women who had endometrial cancer had an average melatonin level of 6. There was little overlap between groups – by using melatonin levels alone, 94% of the patients could have been correctly categorized. A 1992 report proposed that decreased melatonin levels could contribute to endometrial cancer.
Melatonin declines rapidly as we age, with levels generally minimal by age 70.
Exercise impairs the production of melatonin and exercising in the evening decreases melatonin for up to 3 hours afterwards.
People with higher levels of melatonin might be less likely to develop cancer, and people with lower levels seem to be more likely to develop at least some forms of cancer. At pharmacological levels (5-50mg), melatonin seems to be useful in fighting active cancers. Neither of these effects are huge – a lack of melatonin does not always cause cancer, and a large dose of melatonin does not always cure cancer. However, both effects seem large enough to be important.
Based on questionnaires from 78,562 women participating in the Nurses' Health Study, reports that women who worked 30 or more years on the night shift, with at least three night shifts per month, had an almost 40% greater risk of developing breast cancer compared with those who worked the usual day shift.
A second study reported that nighttime bright light exposure is linked to increased breast cancer risk. It is possible that exposure to more light at night – a common phenomenon in industrialized nations – may account for increased cancer risk in women, independent of night-shift work. Another study found only a suggestion of greater risk with the brightest bedrooms, and no additional risk when turning on a light temporarily during the night. [J Natl Cancer Ins 2001;93: pp.1557-62]
One theory is that decreased levels of the brain hormone melatonin are responsible, since this chemical is known to regulate daily sleep-wake cycles. Previous research suggests that unusually low levels of melatonin, which can be seen if humans are exposed to light during the night, may promote tumor growth. Normally, melatonin levels are highest during nighttime darkness and lowest during the daytime light.
The clinical experience of Dr. Pat Elliott, ND has been that a large proportion of young women with a close family history of breast cancer have low melatonin levels themselves. One researcher noted that for breast cancer, the decline of melatonin corresponds to growth of the cancer. This relationship is correlational, but it does suggest that there might be a causal relationship and that melatonin might fight this cancer.
A more recent study at Brigham and Women's Hospital in Boston also reported that women with the highest levels of melatonin have a breast cancer risk that is 40% lower than those with low levels of melatonin. [Journal of the National Cancer Institute, July 2005] This new study by Dr. Schernhammer and a team at Harvard University was different in that the researchers measured levels of melatonin in the urine of women before and after they developed breast cancer. The researchers found that melatonin levels were sharply lower in women who developed breast cancer, even well before their diagnosis.
Marijuana significantly stimulates melatonin production. Italian researchers found that eight men who smoked a cigarette containing THC (the active ingredient in marijuana), had dramatically higher melatonin levels twenty minutes later. After two hours, their melatonin levels were 40 times higher than baseline. [Lissoni, P., Resentini, M., and Fraschini, F. "Effects of Tetrahydrocannabinol on Melatonin Secretion in Man." Hormone and Metabolic Research 1986; pp77-78.]
The fact that smoking marijuana is accompanied by a dramatic increase in melatonin production may explain some of the drug's other positive effects.
Eating regular meals in the recommended hearty breakfast / medium lunch / modest dinner pattern can improve melatonin production. It is important to eat a lighter meal at night because the digestive process slows as melatonin levels begin to rise.
Proper exposure to light and dark can improve melatonin production by 50-200%. For optimum melatonin levels you need at least 30-60 minutes of outdoor light daily, preferably in the morning, and you need a very dark room at night. Sunglasses can confuse the brain, so reducing or eliminating their use is recommended. If you can not be outside or you live in a dark, gloomy climate, full spectrum indoor light can help. If you cannot darken your bedroom, use a sleep mask.
Regular and adequate sleep is the major controlling factor in maintaining normal melatonin levels.
Exercising in the evening decreases melatonin levels for up to 3 hours afterwards, at precisely the time of day when they should be rising. Decrease exercise and/or try to exercise earlier in the day.
Saliva testing is currently the most widely available test and several laboratories offer it.
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