Multiple concussions, particularly when sustained within a short period of time, can lead to chronic inflammation in the brain.  A recent study exploring the effects of repeat concussions found that there is a “strong association between a previous traumatic brain injury and the risk of dementia.” (1)  A pretty frightening conclusion for those who participate in high risk sports.

A key player in the increased risk for dementia is the chronic activation of microglia cells.  Microglia cells function as the “housekeepers” of the brain.  They clean up debris, refine neural circuits, and play a major role in brain plasticity.  Microglia help shape and maintain a healthy brain.  The major tasks of the microglia cells can be broken down into:

1. Immune response to injury and infection. This state is pro-inflammatory. 

2. Housekeeping. This state is anti-inflammatory. 

When there is no active infection or injury the microglia are in housekeeping mode - keeping neurons healthy and playing an important role in memory formation and learning.  When a concussion occurs, the microglia switch into a pro-inflammatory state.  Inflammation is great for responding to an infection or injury, but can cause damage when it does not “quiet down.”  Clinical and experimental studies show that this pro-inflammatory state can last for months to years after a single concussion. (2)   This means that even a single concussion can lead to chronic inflammation.  If you get another blow to the head, even a mild one, while the microglia are still in a pro-inflammatory state, the microglia will produce even more inflammation for an even longer period of time.  The cumulative effect of multiple concussions results in microglia that are in a constantly activated, inflamed state.  Chronically activated microglia are associated with a whole host of disease processes including dementia, depression, Parkinson’s, Chronic Fatigue Syndrome, Fibromyalgia and Alzheimers.  

Countless research papers on the pathophysiology of concussions conclude that calming down overactive microglial cells is a promising therapeutic target.  To my knowledge, there are currently no medications that can do this safely and effectively.  Fortunately, there are safe, natural compounds that can.  One of the most powerful categories of compounds with the ability to calm down overactive microglial cells are Nfr2 activators. (3) The Nrf2 pathway regulates the expression of a set of antioxidant, anti-inflammatory and detoxification genes, protecting the body from oxidative stress.  A variety of natural substances including green tea extract, curcumin, sulforpphane (found in cruciferous vegetables), and specially designed supplements like Nrf2 Catalyst have been shown to activate the Nrf2 pathway, calm down microglial cells, and protect the brain.