---
title: "Book review: “Self Defence – A Myth-Busting Guide to Immune Health”"
date: "2026-10-22T10:41:08+01:00"
modified: "2026-10-22T10:41:54+01:00"
url: "https://newhumanist.org.uk/articles/book-review-self-defence-a-myth-busting-guide-to-immune-health/"
post_id: 11046
---

# Book review: “Self Defence – A Myth-Busting Guide to Immune Health”

![](https://newhumanist.org.uk/wp-content/uploads/sites/2/2026/10/9781847927569-1-1200x830.jpg)***Self Defence – A Myth-Busting Guide to Immune Health*** (Vintage Publishing) by Daniel Davis

I can’t quite place when I first heard that vitamin C was good for the immune system, but I know I was young. So young that I vividly remember a day at school when I started feeling ill and bought myself a glass of orange juice at the cafeteria. I drank it all, convinced it would make me feel better straight away. It didn’t. My dad had to pick me up, and I stayed in bed for a couple of days to recover.

It turns out I was a victim of the long-lasting myth that vitamin C can cure a cold. The idea has been around for decades, boosted by popular researchers who cherry-picked data to prove a point. Immunologist Daniel Davis sets out to debunk this and other health myths in his latest book, *Self Defence*.

Are we more likely to get ill when we’re stressed? Can exercise help prevent cancer? And can we really boost our immune systems by drinking probiotic yoghurts? Davis tackles these questions and others, and he does so with a clear commitment to robust, evidence-driven science.

*Self Defence* offers an open window into the complexity of the immune system. Davis highlights what we know while carefully working through the nuance and uncertainty of areas we don’t yet fully understand. This means the book explores some clear-cut truths: stress does affect our immune system, a good night’s sleep supports immune health, and ageing shapes it in multiple ways. It also looks into some ideas that are simply not evidence-based: gut microbes are important, but it’s unlikely that yoghurt drinks can really “boost” your immune system to stop you getting ill. There’s also no clear evidence that sitting is the “new smoking” and that it harms our health as much as some headlines claim.

*Self Defence* also examines what remains unclear. For example, the effects of exercise on immune health are not straightforward; probiotics may influence the microbiome, but it is difficult to test whether they meaningfully support immune function. These open questions run throughout the book.

It is in these messier areas – the knotty, unresolved science – that Davis is at his most compelling. He builds layered explanations, drawing on a wide range of studies that he presents with care. Readers are made aware of caveats, potential conflicts of interest, and even the size of study samples, all of which shape how conclusions should be interpreted.

This makes *Self Defence* a demanding work of non-fiction. It rewards slow reading and a willingness to pause to take in new knowledge. This density, however, feels justified. Like many areas of science, immunology is inherently complex. Even the simplest definitions – what an immune cell is, what it does – require patience, especially for those who have not engaged with science for some time. And it is precisely through these slower, more detailed chapters that the book delivers its greatest impact.

Reading *Self Defence* led me to a renewed appreciation of the human body and its underlying biology. Take senescence: over a lifetime, cells that become damaged can switch into a kind of dormant, “zombie” state rather than continuing to multiply. It’s a smart safety mechanism our bodies have. I also learned that T cells, the immune system’s specialised attackers, undergo inspection before they circulate. And gut microbes are in constant dialogue with the immune system, producing molecules that calm it down and prevent it from overreacting. Learning all of this deepened my understanding while reinforcing just how intricate immune processes are. The book does not flatten that complexity; it instead asks the reader to sit with it and appreciate the body’s defence mechanisms.

Ultimately, Davis achieves what he set out to do: careful, satisfying myth-busting. In an age of social media, misinformation and AI slop, books like *Self Defence* matter – and they surely do more good than any glass of orange juice ever could.