Andrew Papanikitas is Deputy Editor of the BJGP.
On the face of it, the book appeared to be a very specialised kind of popular science text about the immune system in relation to health. When I stated reading, however, I found myself intrigued, outraged, and occasionally laughing out loud. And this makes sense because our immune system is a complex and story-laden set of ideas with implications for how we live our lives. Naturally, all manner of amusing and occasionally annoying myths abound. It is nice to read a well balanced, or dare-I-say healthy, approach to health messages in this book.
The book takes its myth-busting duty seriously warning the reader early about hype, correlation, and prejudice. Davis tells us of a UK High Street chain that has 276 products listed under the category of immune-support supplements. Such products tend to be regulated under food law which has a focus on safety, which does not require scientific proof of efficacy to the same standards as would be required for medicines. I wonder how the market would look if they did.
Davis tells us of a UK High Street chain that has 276 products listed under the category of immune-support supplements.
There are some general lessons about correlation. For example we could correlate skin cancer with eating ice cream, given the higher prevalence of skin cancers in sunny countries (I tend to use the one about the vast majority of people in car crashes wearing shoes but arguably ice cream works better in context). This is where immune evidence looks to clearer statistical and mechanical links to disease and therapy including molecular mechanisms.
For example, I am taken with the idea of better understanding about how lifestyle factors such as chronic stress might persistently elevate cortisol and thus dampen down immunity. I also read that obesity is a factor implicated in the risk of cancer. Davis tells us about immunology research which suggests that natural killer cells and killer cells are affected by a high fat diet in mice. These cells subsequently find it harder to attack and kill tumour cells in those mice. He is at pains to avoid a simple one size fits all explanation here. Whilst a high fat diet could be a cancer risk, that doesn’t mean that slim people avoid other risks of cancer. He goes on to discuss the mechanical effects of obesity on illness with a discussion of COVID-19 and flu. This is what we would expect: Excessive fat mechanically limits lung expansion, and thus increases the general risk of complications from respiratory disease. Conversely he cites a 20-year study that followed over 3000 people and found losing weight improved to respiratory health.
If garlic wards off vampires, I thought to myself, could you use vitamin C on zombies?
David also invites us to consider our own prejudices and received wisdom. An infamous example of this is the idea that drinking orange juice will help you get over a cold because of the effect of vitamin C on the immune system. He roundly debunks this. And then I read that in 2023 the computer game Fortnite included a feature whereby characters could go to an immunity station and drink a virtual probiotic yoghurt to boost resilience! As I chuckled, I wondered how many health messages are rightly and wrongly encoded in our media and the way we tell stories to one another. If garlic wards off vampires, I thought to myself, could you use vitamin C on zombies? Or maybe just live yoghurt?
It’s a complicated story but Lewis tells it well with references to current media and to key points in the recent history of medicine -some heroes of medical science come off worse for it. Immunity affects us all differently and there is no one size fits all path to immune health. There are however general threads that lend this book more than just intellectual value. Having read it you may be less likely to waste money on spurious health products. You may be less stressed about letting children play in the garden and you may be better prepared to consider whether advice applies to you.
Featured Book: Daniel M Davis , Self-defence: A myth busting guide to immune health, (also published in paperback under the title Immune health: A myth-busting guide in May 2026). Bodley Head, London, 2025, ISBN 978-1847927569, 304 pages, Hardback, £22
Featured Photo by Denny Müller on Unsplash
