Part 1: Health advice can be harmful

Download Part 1: Chapters 1 to 4.

Chapter 1: This book could save your life

Health information can be misleading for many reasons. You cannot always rely on the popular sources of health advice, such as the media, family and friends. Even health professionals are not always well informed about the benefits and harms of tests and treatments. Sometimes new health interventions are introduced before their benefits and harms have been properly established. Conversely, years may pass before tests and treatments of proven benefit become widely used.

This book aims to help you become more informed about your health care and health decisions. It will equip you with some simple tools for distinguishing between reliable and unreliable health advice.

It is not intended to be used as a do-it-yourself guide to becoming your own doctor. We hope instead that it will encourage you to work in partnership with health professionals, whether you are seeing a doctor, psychologist or naturopath.

Chapter 2: Be Sceptical

What has not been examined impartially has not been well examined. Scepticism is therefore the first step towards truth.
(Denis Diderot, Pensee Philosophique)


Many people are more gullible than they realise. Becoming a critical thinker and more aware of your own biases and decision-making processes may help you to make better health decisions. This chapter reveals some of the tricks that marketers and advertisers use to promote products. Just because something works on rats or on cells in a laboratory test tube or for a celebrity does not mean it will improve your health. Nor should you believe everything that is reported in the media about health. What you need is reliable evidence proving that a product works in humans. The evidence should also be relevant to your needs and situation.

Chapter 3: Bad evidence

I'm always certain about things that are a matter of opinion.
(Charlie Brown, Modern Philosopher)


There are many factors to consider when assessing research findings. When a study shows that two health events or characteristics occur together, this does not necessarily mean that one causes the other. Nor can you assume that one person’s experience with a treatment or illness will have any relevance for other people. Even if someone makes a miraculous recovery after a certain treatment, you cannot assume that the treatment deserves the credit. Many problems get better on their own and it is impossible to know whether a treatment ‘worked’ unless you know what would have happenedwithout that treatment. The placebo effect is powerful, and people often report an improvement on almost any therapy, even a placebo (a biologically inactive intervention). Screening tests that detect diseases early are not always beneficial as they can lead to people living more years with disease rather than leading longer lives. Randomised controlled trials - where subjects are randomly allocated to various interventions or a placebo - help address many of these problematic issues.

Chapter 4: Do not always rely on the experts

Medicine is indeed in the middle of an intellectual revolution. Methods of reasoning and problem solving that might have worked well in the past are not sufficient to handle today’s problems. (David Eddy, Medicine, Money and Mathematics)

Many people make the mistake of assuming that experts always get it right. But health care is so complex, with an ever-expanding array of treatments and research findings, that it is impossible for any one expert to stay abreast of all the latest developments. Even those who specialise in a particular field can find this difficult. Traditionally, many experts have based their opinions on unreliable sources - such as advertisements and the opinions of other experts - rather than the results of good-quality studies. To obtain the best possible health care for your needs requires a mix of things, including your practitioner’s clinical skills, the best evidence from the research literature, and a sound understanding of your own preferences based on the chance of benefits and harms from any intervention.