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Although melatonin does many things to try and maintain homeostasis in our bodies, the decline of melatonin as we age doesn't allow melatonin to do this job as effectively as it did when we were younger.
So in thinking about this, I have considered that perhaps melatonin is actually a molecule mechanism built into the body to help prevent population overgrowth. An age related decline of melatonin would help to ensure that people do not live too long as living too long would quickly promote overpopulation of the planet and would result in insufficient food to feed the overpopulated planet. This idea brought forth the question of how the body would know that it needs to reduce melatonin production in order to help prevent overpopulation.
One way that I thought of is through calorie intake. When the body regularly receives a healthful caloric intake, that means there is plenty of food available and prospects are good for continued survival and the body responds to this by decreasing melatonin production at the rate we currently see. On the other hand, if caloric intake declines significantly, as in people are starving, melatonin levels decline even further by 20% in just one week or less as discussed in the following study :
Here is a relevant quote from the study, keeping in mind that this study comes closest to the caloric restriction seen in starving, but not actually starving, as mild to moderate caloric restriction has been shown to have life extending effects :
' Short-term voluntary fasting by total rejection of food or with very limited intake of energy (<300 kcal per day) from 2 to 7 days reduces melatonin concentration in the blood by about 20% (26–28). '
A reduction of melatonin by 20% would significantly lessen the pro health and pro survival effects of melatonin and a very likely outcome from such a scenario would be shortened life expectancy due to increased inflammation, oxidative stress, increased cardiovascular disease, increased cancer rates and reduced total antioxidant capacity. This in turn would likely increase mortality at an earlier age, thereby reducing planet population growth until healthful caloric intake could be restored.
In contrast, increased melatonin intake to try and offset the natural age related decline of melatonin will significantly reduce the number one cause of death in the world, cardiovascular disease (CVD) as I previously discussed here :
https://www.earthclinic.com/cures/melatonin-for-cardiovascular-disease.html
If you significantly reduce the number one cause of death in the world, CVD, it seems a reasonable expectation that people are likely to live longer. When you add the organ protective effects and bone protective effects of melatonin to that equation, increased life expectancy also seems a reasonable conclusion. Adding further to this, when you also take into consideration the multiple anticancer mechanisms of melatonin as discussed in the following link, it seems longer life expectancy due to melatonin is a reasonable idea :
Here is a relevant study quote regarding some of the ways that melatonin works against cancer :
' Melatonin inhibits proliferation of cancer cells through triggering cell cycle arrest and causes cell death by induction of apoptosis. Melatonin suppresses metastasis angiogenesis, and proliferation of cancer cells through affecting various signaling pathways in tumor cells. Melatonin also regulates autophagy pathway in cancer cell by affecting oxidative stress condition in tumor cells. These findings suggest that melatonin may increase the sensitivity of cancer cells to anti-cancer agents and may be a potential treatment for cancers either alone or in combination with other anti-cancer drugs. '
Studies that actually test if long term use of melatonin can extend life expectancy are lacking due to the length of such a study of many years, but given the above effects of melatonin, it seems illogical to think that melatonin would not extend overall life expectancy. So far melatonin has only been used in animal and insect studies in terms of life extension. The following study discusses melatonin and how it showed life extending effects in a small mammal :
https://www.sciencedaily.com/releases/2009/06/090622064807.htm
This is a relevant quote from this 2009 study :
' Under normal conditions, this animal shows the first signs of aging after reaching 12 months, mainly through the loss of circadian rhythm in its activities. By continuously administering melatonin, starting a little before 12 months, the appearance of these first signs was delayed by at least 3 months, which is a considerable period in relation to the lifespan of this shrew*. '
The following study discusses some of the known mechanisms of melatonin by which it can potentially extend life expectancy :
Here is a relevant study quote describing some of the mechanisms by which melatonin may offer life extension :
' MT plays an anti-aging role by upregulating the expression of silent information regulator 1/Sirtuin 1 (SIRT1). SIRT1 is a histone deacetylase, and its physiological function is to remove acetyl groups, bind DNA strands together, and silence a target gene. In 2008, a study reported that MT increases the level of SIRT1 in a mouse model of accelerated aging (SAMP8 mice), demonstrating a positive correlation between MT and SIRT1 for the first time.9 This positive correlation was supported by two other studies.10, 11 MT enhances the deacetylation of SIRT1 substrates by upregulating SIRT1 expression and thus inhibits premature senescence '
Given all of the above information, it would appear that if you get extra melatonin through supplementation or natural means it can be healthful and possibly life extending, but if you continuously have low and or declining levels of melatonin, it may shorten your time to death. Overall, melatonin should make your stay here on earth a more healthful one!
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