Life Extension Magazine September 2012
Beyond Sleep: 7 Ways Melatonin Attacks Aging Factors
By Claudia Kelley, PHD, RD, CDE
#5: Help Delay Alzheimer's Disease
Another unique and powerful property of melatonin is its ability to cross the blood-brain barrier. Oral intake of melatonin has been shown to increase levels of melatonin in the brain.76 Melatonin also protects the blood brain barrier particularly in cases of hypoxic injury that may cause increased permeability of the blood brain barrier and lead to more damage to the delicate brain tissue as compounds that normally would be kept out by a functioning blood brain barrier gain entrance to the brain.77 Intensive research over the past decade has indicated melatonin's beneficial effects in experimental models of neurodegenerative disorders, specifically those linked to oxidative damage.78 In fact, melatonin's broad spectrum antioxidant activity in many central nervous system neurodegenerative diseases has been well-documented and reviewed.78,79
Specifically, melatonin can help delay the onset of Alzheimer's disease (AD) and help protect vital cellular structures, such as mitochondria, from oxidative damage and decay.80 Declines in mitochondrial function are a hallmark feature of many neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and Huntington's disease.81 Melatonin may also promote improved sleep patterns and prevent cognitive impairment and improve the confusion and restlessness that often occurs in the evening (called sundowning) in AD patients.80,82,83 Preclinical studies revealed that melatonin exerts pronounced neuroprotective effects against beta amyloid plaque, one of the specific underlying causes of Alzheimer's disease.84-86
More recent investigations show that melatonin may prevent brain cell death while maintaining energy and oxygen metabolism in highly stressed neuronal mitochondria.87,88 Interestingly, decreased night time melatonin levels have been associated with the severity of mental impairment in dementia patients, and disturbed circadian rhythms seem to be correlated with cognitive performance in elderly and Alzheimer's patients.81,89,90 It is important to note that while melatonin may prove beneficial in earlier stages of Alzheimer's disease, it is much less effective in late stage Alzheimer's and may fail to improve sleep or agitation.92,93
#6: Combat Obesity with Melatonin
In recent years, dietitians and medical experts have recognized that obesity is often associated with stress, emotional eating, sleep-deprivation, and hormonal changes later in life. A recent study in women with night eating syndrome (an eating disorder characterized by late-night binge eating) added further confirmation to this. It found that women suffering from this disorder had pronounced circadian melatonin rhythm disturbances, which also affected levels of cortisol (a stress hormone that can be a factor in weight problems) and ghrelin (a hormone that stimulates hunger). It also affected a variety of other behavioral and physiological circadian markers involved in appetite and neuroendocrine regulation.94
While no human weight-management trials using melatonin have been published thus far,95 preclinical trials are encouraging. In middle-aged rodents, daily melatonin administration was found to suppress abdominal fat, plasma leptin levels, and insulin levels, while also reducing body weight and food intake.96,97 Other researchers reported that melatonin was associated with decreased intra-abdominal fat, decreased plasma insulin and leptin levels, and the absence of age-related weight gain.95,98
Furthermore, laboratory investigations discovered melatonin's ability to activate brown adipose tissue, which encourages your body to burn fat instead of storing it.99-101In recent years, brown fat has increasingly become a target for halting the global obesity epidemic.102 In a rat model of pre-diabetic, diet-induced obesity, supplementing obese rats with 4mg/kg/day of melatonin resulted in reductions in body weight, belly fat, serum insulin levels, and triglycerides.103 In humans, the equivalent dose is 48 mg for a 165 lb adult, which is a very high dose that could produce next day drowsiness. Typical human doses for melatonin range from 300 micrograms to 10 milligrams at bedtime.
#7: Help Prevent Osteoporosis
Data derived from animal research suggests that melatonin has beneficial effects on bone repair and remodeling, and bone mineral density,104 which would make it an ideal candidate for the prevention of osteoporosis or as adjuvant after bone fractures.
A very small, yet compelling recently published double-blind, placebo-controlled pilot study investigated the effects of melatonin on bone health and quality of life in 18 perimenopausal women (ages 45-54) for 6 months. It found that melatonin improved physical symptom scores (e.g., feeling and sleeping better), increased osteocalcin (a marker for bone formation), and decreased levels of Type-I collagen cross-linked N-telopeptide (a marker for bone resorption), indicating that melatonin may restore imbalances in bone remodeling and prevent bone loss.105 However, while the results from this small study appear clinically relevant, further investigation is warranted.
Aging is a multi-factorial process, involving a heavy load of free radicals, metabolic, hormonal, and changes in immunity. Although there is currently no direct clinical evidence demonstrating that melatonin may prolong the human life span, there are several reasons to postulate its role in the aging cascade:
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