Every now and then a book comes along that I feel is worth sharing, and The Angel and the Assassin: The tiny Brain Cell that Changed the Course of Medicine, by Donna Jackson Nakazawa is one of those books. Jackson Nakazawa takes a complicated topic—the function of a specialized brain cell called microglia—and breaks down her message into a fascinating story that reads a little bit like a detective novel.

As she explains it, microglia are a type of glial cell in the brain that function like microphages—themselves a type of white blood cell that consume unhealthy substances in the blood.  They compose about 10% of all brain cells, and yet their function was overlooked until the past few years.  Scientists have now realized that the brain has an immune system response, and microglia are the brain’s version of white blood cells, swooping up what doesn’t belong.

When microglia are functioning well, they secrete what is needed to stimulate the growth of new neurons and make new synapses, as well as the growth of myelin—the protective sheath around brain cells that works like the protective cord covering the wiring on all electrical devices.  These important functions are what help keep our brains healthy.

Interestingly, The Angel and the Assassin looks at what happens when microglia get overactive. Microglia can start consuming parts of the brain that should not be consumed, much like white blood cells can get overactive, leading to auto-immune disorders.  The scientists Nakazawa Jackson interviews point to overactive microglia as inflammation in the brain and show how this, and not the long-debunked chemical imbalance theory, is behind mental health disorders. She points to several promising approaches to resolving this, such as fasting-mimicking diets, transcranial magnetic stimulation, and neurofeedback.

I will be keeping a copy of this fascinating book in my office for clients who wish to borrow it, and I encourage anyone who knows someone who suffers from mental health problems to pick up a copy of this book. It’s likely to change how you look at mental illness and physical wellness.