334 Glymphatic System [31 August 2015]

Last week I listed adequate deep sleep as one of the ways we can reduce our risk of developing dementia. It deserves a closer look.

The brain comprises 2% of our body by weight but consumes 25% of our energy (no wonder thinking makes us tired!). The brain therefore creates a proportionately larger amount of waste products that need to be removed.

If you look at a chart of the lymphatic system, one of whose functions is the removal of waste products from our cells, you will notice that there are no lymphatic vessels in the brain. How then does the brain clear its waste?

New imaging methods allowed researchers at the University of Rochester Medical Center to finally answer that question. They discovered that the cerebral spinal fluid (CSF), which surrounds the brain and spinal cord, periodically flushes through the brain. The CSF follows along the blood vessels – in along the arteries and out along the veins – thanks to special brain cells called glial cells. This flushing, called the glymphatic system, removes the waste products from the spaces between the brain cells. Surprisingly the researchers discovered that this flushing activity occurs almost exclusively during sleep when the brain cells shrink by 60% and the interstitial spaces are larger. Furthermore this flushing activity appears to be most effective during deep sleep.

One of the waste products removed by this CSF flushing is a protein called amyloid beta which is normally produced in the brain. A buildup of this protein forming amyloid plaques is one of the characteristics of Alzheimer’s disease. It appears that lack of sleep could be an important factor in allowing amyloid beta to build up in the brain.

Besides increasing risk of developing dementia, sleep deprivation has more immediate effects – even one night of insufficient sleep can impair our ability to think clearly, solve problems, make good decisions, exercise self-control, cope with stress, and come up with the right words in conversation.

We know from our own experience that a good night’s sleep refreshes the mind (or at least that lack of sleep muddles it!). Clinical studies have linked poor sleep to an increased risk of Alzheimer’s disease. The newly-discovered glymphatic system could explain both, and give us another good reason to ensure we get enough quality sleep every night.

Sources:
Mercola - Sleep & Alzheimer's
Ted Talks - Jeff Illiff, U of R researcher

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.