The pineal gland releases less and less melatonin as we age, and thus blood and brain levels of melatonin decline very significantly as we age. Numerous studies now show that the decline in melatonin is a major factor in making our brains more prone to memory loss, dementia and Alzheimer’s disease in the aging process. As such, a number of investigations and clinical trials have been performed in recent years to see if melatonin supplementation given to adults can block steps in Alzheimer’s disease development and/or help improve memory loss problems in patients with existing Alzheimer’s disease or mild cognitive impairment, which is the step prior to developing Alzheimer’s disease. Animal studies have been very clear in showing that animals that are bred to develop Alzheimer’s disease or where Alzheimer’s disease has been induced via the administration into the brain of the toxic drug streptozotocin (STZ), that melatonin supplementation blocks many of the steps in Alzheimer’s disease and improves or restores memory function.

More specifically, melatonin has been shown to help prevent several key aspects of Alzheimer’s disease development:

1. Blocks the synthesis of toxic beta amyloid plaque in the brain
2. Enhances the clearance of beta-amyloid plaque from the brain
3. Blocks the synthesis of toxic neurofibrillary tangles by maintaining normal tau protein structure and function
4. Helps prevent shrinking of the hippocampus (where short-term memory becomes consolidated into long-term memory in the brain)
5. Helps to maintain the volume of the lamina cribosa (LC) of the optic nerve. A reduced volume of the LC is highly correlated with atrophy of the hippocampus and Alzheimer’s disease development

As reviewed in the 2020 publication in the Medical Science Monitor, clinical trials on humans have now shown that melatonin supplementation can reverse early-stage memory loss (mild cognitive impairment) in a significant percentage of cases.

Melatonin supplementation has also been shown in human imaging studies to help maintain the volume of the hippocampus and the lamina cribosa. As well melatonin supplementation administered to early-stage Alzheimer’s patients has, in many cases, improved their memory and has helped to improve sleep quality and duration and has reduced feelings and expression of agitation in the late afternoon, defined as sundowning.  For me the take-away message is very clear – by age 40 or 45 most of us should consider taking 1-2 mg of melatonin (about an hour before bedtime) to help restore more youthful blood and brain levels of melatonin. Not only does it help to improve sleep quality, but it helps prevent free radical damage to the brain, blocks key steps in Alzheimer’s disease development as I have outlined, it helps preserve more youthful functioning of our immune system (helping to reduce risk of infections and cancer), it has some direct and indirect anti-cancer properties, and it turns on the longevity genes in our cells, known as Sirtuin genes, which are linked to longer and healthier lifespan.

I personally take a melatonin supplement that also contains 5HTP, GABA and Bacopa monnieri, as they all work together to improve memory, mood and sleep quality, and the melatonin confers the other benefits I have described in this update. I have included the key references for melatonin and Alzheimer’s disease in the text below.

References:

Xu L et al. Dietary Melatonin therapy alleviates the lamina cibrosa damages in patients with mild cognitive impairments: A double-blinded, randomized controlled study. Medical Science Monitor. May 7, 2020. Medical Science Monitor | Dietary Melatonin Therapy Alleviates the Lamina Cribrosa Damages in Patients with Mild Cognitive Impairments: A Double-Blinded, Randomized Controlled Study – Article abstract #923232

Li Y et al. Melatonin regulates beta-amyloid plaque production/clearance balance and beta-amyloid neurotoxicity: A potential therapeutic molecule for Alzheimer’s disease. Biomedicine & Pharmacotherapy. December 2020. Volume 132. Melatonin regulates Aβ production/clearance balance and Aβ neurotoxicity: A potential therapeutic molecule for Alzheimer’s disease – ScienceDirect

Andrade M et al. Melatonin reduces beta-amyloid accumulation and improves short-term memory in steptozoticin-induced sporadic Alzheimer’s disease model. IBRO Neuroscience Reports. Han 26, 2023. Melatonin reduces β-amyloid accumulation and improves short-term memory in streptozotocin-induced sporadic Alzheimer’s disease model – PMC

Eat Smart, Live Well, Look Great,
Dr. Meschino