The Glymphatic System: New Discoveries On Sleep And The Aging Of The Brain
Our Brain’s Newly Discovered Lymphatic System
Somehow, despite thousands of neurosurgeries and thousands of brain images, we missed it: there is a system of drainage vessels buried under the dura mater, the leather-like outer layer that surrounds the brain. It was theorized to exist in 2015 and definitively found in 2017. The glymphatic system is the lymphatic system of the brain, responsible for removing pathological proteins, including amyloid, that build up during the course of the day. The glymphatic system functions primarily during sleep, and mainly during the deeper phases of sleep, medically termed “N3” sleep. As we age, our other two systems of brain “cleaning” slow down, our sleep quality deteriorates, and metabolic debris, along with amyloid, begins to stack up… another challenge of aging.
Sleep And Healthy Aging Of The Brain
It is impossible to overstate the importance of sleep quality and quantity for healthy aging of the brain and avoidance of neurological illness. Sleep dysfunction is directly linked to reduced glymphatic function. The vast percentage of glymphatic activity occurs during N3 sleep. During this stage of sleep, slow oscillatory brain waves increase glymphatic clearance up to 90% relative to the waking state. As we sleep, levels of norepinephrine (a form of adrenaline) decline leading to the relaxation of glymphatic vessels, which in turn decreases resistance and increases cerebrospinal fluid flow, which bathes the brain and spinal cord, refreshing nutrients and sort of washing away metabolic waste. Taurine is an amino acid which may be neuroprotective by improving glymphatic activity via reducing stress hormones and neurotransmitters like norepinephrine. Also taurine, by acting on brain fluid receptors, protects against molecular stress conditions by “refolding” proteins, preventing the build-up of amyloid and other protein aggregates that accumulate during aging.
Glymphatic Activity: Optimizing Brain Wellness
In addition to addressing sleep practices and optimizing brain wellness through consistent and efficient glymphatic activity, vascular health (blood vessels) is another important component of glymphatic function. The dynamics of the glymphatic system are based in part on arterial wall pressure in small blood vessels in the brain. Disturbances in the brain’s vascular network due to atherosclerosis or plaque build-up or hypertension will reduce the elasticity of smooth muscles and harm glymphatic function. This dependence likely explains the co-morbidity between cardiovascular disease, cerebrovascular disease, and risk of neurodegeneration. So, to take care of our brains, we have to care for our blood vessels too.
Many dietary and lifestyle choices can help or hurt the glymphatic system and the brain. Oleuropein aglycone, the main polyphenol found in olive oil, is best known for its blood pressure-lowering effect, but also has a neuroprotective function, by preventing the toxic aggregation of both amyloid beta and tau proteins. The active polyphenols contained in extra virgin olive oil (oleuropein, tyrosol, and hydroxytyrosol) also have strong anti-inflammatory effects which have been shown to reduce inflammatory cytokines, including TNF-α, IL-1β, and IL-6. This in turn helps to improve the circulation in blood vessels surrounding the glymphatic system, helping to relax vasoconstrictive pathways in the brain and thereby promote brain wellness. Adequate intake of omega-3 fats (found in fish oil), minimal alcohol exposure, proper stress management, exercise, introduction of some fasting, along with many plant foods, are all factors that promote the care and cleaning of the brain through augmenting glymphatic clearance.
HVLM: Committed to Health Brain-Aging
In our practice at HVLM, we are committed to aging healthfully with all of our mental faculties intact. This is not something we can take for granted. We evaluate all of the foundational habits relating to brain aging. We can help you quantitate and assess your deep sleep, measure your omega 3 level in your cells, develop an intermittent fasting plan that is achievable, design an exercise program, and build a dietary plan that incorporates brain-healthy foods. Just like our cars, our homes, and our computers, our brains need attention before the “check engine” light alerts us that we have a problem!
Resources
Scientists Somehow Just Discovered a New System of Vessels in Our Brains [By James Hamblin, The Atlantic]: https://www.theatlantic.com/health/archive/2017/10/scientists-somehow-just-discovered-a-new-system-of-vessels-in-our-brains/542037/
The Sleeping Brain: Harnessing The Power Of The Glymphatic System Through Lifestyle Choices
[Oliver Cameron Reddy and Ysbrand D. van der Werf, National Library of Medicine]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7698404/
Not All Sleep Is Equal When It Comes To Cleaning The Brain [University of Rochester Medical Center, Science Daily]: https://www.sciencedaily.com/releases/2019/02/190227173111.htm
