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Taking out the Brain Garbage
The glymphatic system only works at night
While researching information on the brain and its need for cholesterol, I ran across a topic I’d never heard of before: the glymphatic system within the brain. That took me down a rabbit hole, which resulted in this substack.
The central nervous system (CNS) is the only organ in the entire body that lacks its own, defined lymphatic drainage system. As a result, the Great Architect created unique adaptations for achieving fluid balance and waste removal called the glymphatic system.
The glymphatic system, which is short for glial-dependent lymphatic transport, was only recently discovered (2012). It is a waste clearance system that utilizes a unique system of channels formed by astrocytes to promote the elimination from the central nervous system (CNS).
Importantly, the glymphatic system functions during sleep and is mostly quiet during wakefulness. The biological need for sleep across all species reflects that the brain must enter a state of inactivity. During sleep it eliminates neurotoxic waste products, including β-amyloid.
In addition, the glymphatic system, and hence sleep, contributes to the reduction of brain lactate. The accumulation of lactic acid (lactate) in the brain promotes deposits of Aβ proteins, the main feature of Alzheimer’s Disease. Excessive transmission of lactic acid into neurons in the brain leads to acidity (lactic acid quickly becomes lactate + hydrogen atoms [H+]). This acidic environment leads to mitochondrial function failure and cell death (apoptosis), both have an adverse impact on brain function. The mitochondria are the organelles that produce the energy (ATP) needed by all cells to live. All data presented within several reports support the notion that glymphatic clearance plays a key role in lowering brain lactate concentration and improves brain health.
The Importance of Sleep
Why do we spend one-third of our lives asleep? Why does the daily sleep amount decrease from birth to maturity in all terrestrial mammals? And why do we have two kinds of sleep, rapid eye movement (REM) and non-REM (NREM) sleep? Brain energy metabolism only declines by 25% during sleep suggesting that sleep does not simply function to conserve energy. Multiple studies indicate that sleep enhances memory, however, the biological need for a specific quantity of sleep is unclear.
There are no shortage of theories to explain the functions of REM and NREM sleep.
How is sleep defined? Sleep is a state of relative immobility in which there is greatly reduced responsiveness. It is distinguished from a traumatically induced or a anesthesia-induced coma by its rapid reversibility.
An additional defining characteristic is that when sleep is prevented, the body tries to catch up on the lost hours. While sleep is essential for all mammals, the decreased alertness increases the chance of being targeted by predators. The argument that sleep serves a vital function is compelling. Sleep deprivation in rodents and fruit flies can cause death more quickly than food deprivation.
As previously mentioned, the central nervous system (CNS) is the only organ system lacking lymphatic vessels to assist in the removal of cellular and metabolic waste products. The glymphatic system is constantly filtering toxins from the brain, but during wakefulness, this system is barely working at all. Besides waste elimination, the glymphatic system also helps to distribute glucose, lipids, amino acids, and neurotransmitters throughout the brain, all important for optimizing brain function.
The role of sleep in glymphatic clearance has been conclusively demonstrated. Sleep is a primary driver of the macroscopic removal of brain toxicities. However, research on lifestyle choices such as sleep quality, sleep quantity, sleep hygiene, physical exercise, chronic stress, intermittent fasting, omega 3s for brain nutrition, and the effect of low doses of alcohol have only recently begun to emerge.
Options for Improving Sleep
If you don’t sleep well, or don’t sleep through the night, it’s important to re-evaluate your sleep plan. It’s obvious by learning about the glymphatic, to decrease your risk of Alzheimer’s disease by assisting in the removal of neurotoxic β-amyloid. One mouse study showed that head position during sleep also modifies flow through this pathway: laying on the side cleared toxicities better than laying on the back or stomach.
I can assure you that after researching the glymphatic system, which I knew little about, I have a whole new appreciation for sleep quality and sleep quantity. Quite honestly, I’ve always looked at sleep as a “necessary annoyance” rather than an essential part of health, particularly brain health. From the time I was very young, I never needed much sleep. In fact, when I was in elementary school, and when I was deciding to become a doctor, I made the claim - more than a few times! - I wanted to go into research to develop the pill that you’d never have to sleep. Afterall, it took up so much time, and there were so many things I’d rather do!
I’m seeing it differently. Especially now.
Since this stroke, I do my best to get at least 7 hours of sleep each night, often more, and I take naps when I’m tired. About an hour before my intended sleep time, I take three Opti-Natural ZZZs along with Melatonin 3 mg, which comes as a pill or a lozenge in our store.
I also take phosphatidylserine. This nutritional supplement promotes better cognitive function and memory. This is especially important as we age, supporting how our brain cells communicate and enhancing the ability to metabolize glucose and lactate for brain energy. Since very little phosphatidylserine is found in food, the compound must be supplemented to provide what is needed for optimal brain health. Our super clean soft gels provide 100 mg of purified, high-concentration phosphatidylserine sourced from sunflower oil, making it easy to achieve therapeutic dosing.
I then make sure my bedroom is dark, cool, and quiet, and Teegan, my puppy, is settled in for the night! If you’re a night owl like I have been my whole life, it may be time to take sleep a little more seriously.