By Claudia Kelley, PHD, RD, CDE
While melatonin is involved in regulating our internal body clock, that's just the beginning of its health-promoting benefits. Based on extensive research, scientists have discovered that this hormone has beneficial effects on everything from heart disease and diabetes, to bone health and obesity. And best of all, emerging science now suggests that it may protect our genetic material and guard against age related disease and decline.1
Preclinical studies found that melatonin increased the life span of animals by up to 20%—prolonging their youthful character in the process.2-4 Scientific evidence now suggests that melatonin plays a crucial role in a variety of metabolic functions,5 including antioxidant and neuroprotection,6,7 anti-inflammatory defense,8 and immune system support.9
Because melatonin production reduces with age,10-14 experts believe that its decline contributes to both the aging process and a generalized deterioration of health.5,15-17 Years ago, scientists could only speculate at the underlying mechanisms behind melatonin's anti-aging properties. A growing body of evidence reveals how melatonin is able to play such a major role in the combating aging process.18-20
#1: Antioxidant Defense—Combat Free Radical Damage While You SleepSince its discovery over 50 years ago, melatonin has demonstrated itself as a functionally diverse molecule, with its antioxidant properties being amongst its most well-studied attributes.26,27 Since then, a vast amount of experimental research has revealed its vital role in the body's defense against numerous cell-damaging free radicals—and for good reason.27-30 Melatonin has been found to possess 200% more antioxidant power than vitamin E.31 Melatonin has been found to be superior to glutathione as well as vitamins C and E in reducing oxidative damage.6
As such a potent antioxidant, melatonin plays a powerful role in fighting free-radical-related diseases—from cardiovascular disease to cancer and practically everything in between.
In post-menopausal women, for example, melatonin has been found to inhibit lipid peroxidation (damage to your fat cells caused by free radicals), thus leading to decreased levels of low-density lipoprotein (LDL) cholesterol,31 one of the primary ingredients for the formation of atherosclerosis. A newer study on men confirmed these findings, suggesting that melatonin leads to overall lower levels of oxidative stress in humans.32 In individuals undergoing cardiopulmonary bypass surgery, melatonin exhibited a higher reduction in lipid peroxidation and improvements in red blood cell membrane stiffness.33
Other widely feared free radical diseases, such as age-related macular degeneration (AMD),34 acute respiratory distress syndrome (ARDS),35 glaucoma,36 and sepsis37 have also been responsive to increased melatonin levels.
#2: Melatonin Fights Back Against America's Major Killer
Other investigators reported that it decreases total cholesterol and LDL levels and increases HDL cholesterol levels.33,34 Scientists have discovered that individuals with metabolic syndrome have a lower melatonin production rate compared to healthier counterparts without metabolic syndrome and that individuals with metabolic disturbances in blood pressure, cholesterol, and blood sugar management (all classic features of metabolic syndrome) possess lower melatonin levels than those with normal metabolic function.47 Additional in-vivo studies have confirmed that melatonin can lower blood pressure levels.44-48
#3: Cancer Therapy Adjuvant and Immune RegulatorEmerging research suggests that melatonin has anticarcinogenic properties—that is, it has the ability to prevent cancer from occurring, or to induce the cancer cell death if it does occur. This has been attributed to melatonin's antioxidant, anti-inflammatory, anti-proliferative, and hormone-modulating properties.49,50
Melatonin's ability to interfere with cancer cell multiplication and growth ("proliferation"), as well as inducing cancer cell death ("apoptosis"), has been documented in cancer patients.51, 52
It has been successfully used in individuals with advanced stage cancers undergoing conventional anticancer therapy, by either slowing disease progression and/or decreasing treatment side effects.53-60 In a review of 8 randomized, controlled clinical trials evaluating the benefits of melatonin as an adjuvant therapy for cancer patients with solid tumors undergoing chemotherapy or radiation therapy, researchers found that concurrent use of 20 mg of melatonin once daily versus conventional treatment alone, improved the rate of complete or partial remission by nearly 50%, increased the one-year survival rate by 45%, and decreased the devastating side effects of conventional therapy such as low platelet count, neuropathy, and fatigue by 89%, 83%, and 65% respectively.59 What's more, these effects were consistent across different types of cancer and there were no adverse events reported.59
Melatonin's anticarcinogenic properties can also be attributed to its effect on your immune system. Laboratory studies revealed that melatonin can activate T-helper cells, which triggers other immune cells in order to help kill off foreign invaders or pathogens.61,62 Additionally, melatonin stimulates natural killer cell, monocyte, and macrophage synthesis, and has been found to facilitate healthy cell-to-cell communication, which enhances the body's appropriate immune system response to foreign invaders.63,64 Based on available evidence, leading experts suggest that patients with cancers and particularly metastatic solid tumors, might benefit from melatonin use, potentially leading to improved therapeutic outcomes.62-70 Certainly, more research is warranted.
#4: Protect Against Diabetic Complications
Melatonin has also been shown to protect pancreatic beta-cells and several diabetes-affected organs (including kidney, retina, brain, and vasculature) from free radical damage.75 In studies, melatonin treatment has produced reductions in blood glucose, hemoglobin A1c, and cholesterol.75
Scientists see great promise for melatonin's potential to improve quality of life by alleviating many of the complications associated with diabetes, such as retinopathy, nephropathy, and cardiovascular disease.49,74,75