Is it true that orange juice can help ward off colds? How does age effect our immune system? Is mental health really connected to inflammation?

We are surrounded by bold claims and quick fixes for ‘boosting’ our immune health. But one thing the science is clear on is that everyone’s immune system is completely unique – what is good for one person may not work well for another. So how do we separate the bogus claims from the useful advice? And given its sheer complexity, is there anything we can do to improve our immune system?

In this expert guide, world-leading immunologist Daniel M. Davis examines the effects of stress, diet, age, exercise, the microbiome and more on the immune system, punctures the key myths, sorts the fact from the fiction and equips us to make informed choices for ourselves.

Praise

Self Defence: A Myth-Busting Guide to Immune Health uncovers how curiosity-driven science can help you truly understand and optimize your immune system—free from hype, misconceptions, and the traps of mistaking coincidence for causation. From the surprising links between cytokines and mood to the effects of stress on immunity, this book reveals how our biology shapes us in unexpected ways. With stories like how a glowing jellyfish transformed medical research, it shows how simple discoveries can lead to profound insights. Dive in to see how thoughtful, evidence-based exploration can lead to better health, resilience, and self-awareness.
Roger Highfield, Science Director, Science Museum

‘The body is hugely complicated. You need a book not a slogan to unravel what helps keep it healthy. Fortunately Davis has written an excellent guide to navigate you through the minefield of theories and speculations about what might boost our immune system. The answer is not easy which is why you want an expert like Davis as your pilot through this difficult terrain.’
Marcus du Sautoy, Simonyi Professor for the Public Understanding of Science at the University of Oxford and author of Blueprints: How Mathematics Shapes Creativity

‘A fascinating guide to the immune system, cutting through the myths with clear, evidence-based science. Daniel M. Davis empowers readers to make informed choices about their health in a world of so much misinformation’
Rhiannon Lambert, Sunday Times bestselling author of The Science of Nutrition

‘A beautifully written overview of the current state of the art in our understanding our immune system. But perhaps even more importantly, this book is an instruction manual which guides the reader through the blizzard of popular science and pseudoscience that inevitably obscures informed discussions about our health.’
Brian Cox

‘Dan Davis’ Self-Defence is a thought-provoking, insightful guide to the immune system’s vital role in protecting our bodies and minds. With clarity and precision, Davis provides a compelling exploration of how we can harness this incredible system to stay well in our ever-evolving world. A must-read for anyone looking to empower themselves with the science of staying well.’
Jenna Macciochi

‘Read this book! Your immune system is notoriously confusing yet vital and thus worth understanding. Fortunately, this succinct, clear, insightful, and fascinating book from one of the world’s experts on immunology will answer your most important questions about how best to help your body defend itself and stay healthy.’
Daniel Lieberman, author of Exercised, The Story of the Human Body, and Professor at Harvard

‘A brilliantly crafted immunisation against the fads, fixes and fraudsters that seek to improve our immune health. Davis draws on the past, present and future of immunology to inform and explain what we can and importantly cannot do. Ultimately what he shows is that the immune system is wondrously complex and that simple soundbites, however persuasive, will have little real impact’
John Tregoning, author of Live Forever? and Infectious

‘The ultimate self-help book. Davis is a captivating and authoritative guide, addressing many seemingly simple questions about our immune health, from vitamins to vaccines, from stress to the microbiome. We learn how to learn about the only thing in the universe that’s arguably more complex than the human brain.

This is genuinely one of the most worthwhile books I’ve ever read.’
Nick Lane

‘Admirably clear, readable and reliable. Davis writes with infectious enthusiasm about the beauty and complexity of human immunity’
Dr Gavin Francis, author of Recovery

‘An engaging and thorough look at the factors affecting our immune health. If you’ve ever been tempted to take steps to ‘boost your immunity’, read this first!’
Sarah Gilbert

‘The immune system holds the key to modern diseases and this great book from a world expert offers practical tips and dispels many myths on how best to enhance it.’
Tim Spector

‘Utterly absorbing. Nearly every paragraph brings a revelation.’
Bill Bryson

‘We all retain some traditional beliefs on what life-styles and everyday remedies are good for us,. This clearly-written book by a distinguish expert tells us which beliefs are grounded in science and which are not. We can all enjoy reading it, and its messages can improve our health’
Martin Rees

‘In a world of sales patter, soundbites and social media videos, scientific rigor, clarity and nuance is much needed. Self-Defence provides precisely that. Davis dissects claims and widely held beliefs surrounding the workings of our immune system, and shines a light on what is myth, hype, uncertainty, or scientific truth. A masterful exploration of what we know (and don’t know) about the workings of this most crucial of bodily functions.’
Guy Leschziner

‘There is so much misinformation in the health and science arena that it can be really challenging to pick the truth out of all that fiction. Self Defence is a perfect antidote to so many of those assumed truths about immune health that have gone unchallenged for way too long. It is a refreshing, expert examination of health myths, beautifully written, packed with science but always accessible. I learned a lot.’
Suzanne O’Sullivan

‘This is the clearest, most authoritative and most honest guide I have seen to the kinds of questions about our health and our immunity that we encounter all the time. What is the best diet? Does exercise help? What does our microbiome really do? Is good sleep so important? With patience, humility, humanity and generosity, Dan Davis provides a primer on immunity that should be on everyone’s bookshelf.’
Philip Ball, science writer and author of How Life Works

‘Cutting through all the myths, marketing hype and simple slogans – this is the best book on immune health I have ever read.Daniel Davis expertly debunks the myths surrounding the immune system – and shares the latest scientific insights into health. The most sensible book on immune health you’ll ever read.’
Alice Roberts

‘In Self Defence, immunologist Dan Davis manages to explain everything that we know about our immune systems with clear, concise, and engaging stories based in the latest science, not hype. So, if you’re tired of all the people trying to sell you things that they swear will improve your immune function, but then never do, this book is for you. Dan walks us through the often complicated answers to all our questions and shows us that they is no such thing as a one-size-fits-all solution to immune health.’
Theresa MacPhail

‘Wellness gets the expert treatment as Davis filters out the bullshit/hype and hearsay in a clarifying sweep to reveal the fascinating complexity around how our body maintains health, and how we can help it.’
Gaia Vince

‘A clear-eyed, myth-busting manual to managing immune health. I learned a lot about what I was doing wrong for so long – and how to set it right.’
James Nestor, author of Breath