INFLAMMATION is a crucial tool of the immune system. As the body鈥檚 first line of defence against injury or invaders, it traps bacteria and viruses, heals wounds and signals to other cells for help, resulting in symptoms such as pain and swelling. Once a threat is remedied, inflammation, along with its ensuing discomfort, disappears 鈥� or at least it should.
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In her debut book A Silent Fire: The story of inflammation, diet and disease, gastroenterologist Shilpa Ravella explains how inflammatory responses can turn against us. Crucially, she shows how chronic inflammation plays a role in many common conditions, such as diabetes, heart disease and cancer, and why Western diets are at least partially to blame.
This primer sees Ravella start with some fascinating history, travelling all the way back to the 1st century, when Aulus Cornelius Celsus first described four of the five main signs of inflammation: pain, heat, redness and swelling. The fifth, a loss of function, was identified in the mid-1800s.
Ravella spends a lot of time with Victorian scientists, such as 茅lie (Ilya) Metchnikoff, who won a Nobel prize in 1908 for discovering immune cells called phagocytes that engulf pathogens and particles. Eventually, she moves on to modern-day researchers like Charles Serhan, who helped identify molecules known as resolvins that turn off inflammation.
This lays a proper foundation for the book鈥檚 second section, which connects these discoveries to inflammation鈥檚 possible role in disease. Low levels of inflammation have been found in people with conditions such as cancer. While inflammation is a normal response to injury and disease, persistent inflammation is now being viewed as a potential cause of illness.
Ravella speculates that inflammation can contribute to conditions like depression (see page 38) and Alzheimer鈥檚 disease, though as a responsible medical professional, she provides important caveats and stresses the need for more research.
The most damning evidence links inflammation to autoimmune conditions 鈥� which occur when the body damages its own cells 鈥� such as rheumatoid arthritis. Characterised by long-lasting, low levels of inflammation, these conditions increase susceptibility to other problems like bone loss, heart disease and kidney disease.
The book wraps up by detailing how factors like diet and exercise can contribute to inflammation as well as help dampen it. For many, this won鈥檛 be new, but what may be illuminating is Ravella鈥檚 explanation of lifestyle鈥檚 significance.
For instance, she devotes a whole chapter to the gut microbiome, describing how processed foods and animal products, like red meat and dairy, disrupt microbial composition, setting off a chain of events that leads to increased inflammation. She then explains why fruits, vegetables and whole grains can help undo these effects.
A Silent Fire is no quick read: it is packed with information, combining medical history, innovative research and first-hand clinical experiences. At times, it feels over-ambitious, as Ravella crams in as much as possible rather than clearly connecting the various topics. It can also be difficult to keep track of all the different microbes, scientists and immune cells involved, especially if you lack a scientific or medical background.
But Ravella鈥檚 writing style keeps even the most dense page engaging. She breathes life into biological functions, at one point describing types of white blood cells as 鈥渟ophisticated warriors鈥� that 鈥渧oraciously gobble up鈥� particles. Ultimately, the book is perfect for those looking to delve deeper into the history and intricate workings of immunology, diet and disease.
