Book review: Why Zebras Don’t Get Ulcers, by Robert Sapolsky

Why Zebras don’t get ulcers (affiliate links: UK, US) is an incredibly popular book about stress and how it can effect our health.  However, it suffers greatly from not referencing any of the other recent, important developments in health and nutrition.  It’s also a bit on the long-winded side (you get the impression that the author tends to do a lot of talking) but it’s a great reference work none-the-less.

Happy, stress-free zebras in the wild

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So it’s about stress?

Yes.  Sapolsky tries to cover all of the key issues about stress in one book.  These are the main chapters:

• Glands, gooseflesh and hormones – Sapolsky describes the basic functions of the sympathetic system, the fight or flight response and the basic hormones involved in the stress response.
• Strokes and heart attacks – this chapter covers the basic research on how stress affects heart disease, by increasing blood pressure.  It’s not the best treatment of the subject because it keeps trying to tie cholesterol and the lipid hypothesis into everything despite the lack of evidence.  Malcolm Kendrick’s discussion of this subject is much better.
• Stress and metabolism – Sapolsky briefly covers how stress seems to affect appetite and digestion, by referencing studies.  He fails to really grasp the nettle, though, because he doesn’t consider how glucose affects insulin.  This is a big failure of an otherwise good treatment.
• Ulcers, the runs and hot fudge sundaes – based on the previous chapter’s explanations, this section discusses how stress affects appetite but again refuses to address how the glucocorticoids increase blood glucose and how this might affect appetite.
• Dwarfism and the importance of mothers – in this interesting section, Sapolsky steps away from the contentious issues and discusses the interesting consequences of pre- and post- natal stress and their impact on growing children.  Sapolsky describes the fascinating case of J M Barrie, who wrote Peter Pan, and how he suffered from this ailment.
• Sex and reproduction – as most people know, stress causes a reduction in testosterone levels but it also affects reproduction in a number of other, smaller ways, which are described in this chapter.
• Immunity, stress and disease – despite huge resistance from mainstream science, it has finally been accepted that the way that organisms perceive their surroundings can have an influence on immunity and disease.  Sapolsky still seems a little stunned by this.  However, this is useful, as he goes on to explain in detail how the mechanisms that are understood work.
• Stress and pain – fascinatingly, experiments on rats (as always) have revealed that previously stressed rats suffer from learned helplessness and fail to learn how to avoid new painful stimuli, which unstressed rats can easily avoid.  Also, the basic sensation of pain can be numbed by other stressors.
• Stress and memory – from an evolutionary standpoint, it makes sense to burn those stressful events into the memory and experiments have shown that this occurs with great predictability.  Sapolsky explains how the sympathetic nervous system activates the hippocampus to create more lasting memories of stressful events.
• Stress and sleep – Sapolsky spends a little time going over the evidence and mechanisms for how stress is created by sleep deprivation and how stress stops us from sleeping properly.
• Ageing and death – Sapolsky’s basic thesis that underlies all of the book is that the stress response is good for short-term stressors but causes damage when prolonged.  He uses this concept to explain the link between stress and ageing, considering ageing as simple mileage.
• Why is psychological stress stressful? – Sapolsky spends a chapter going over the evidence and reasons for why we experience such a stress response as a result of psychological factors.
• Stress and depression – in this detailed section, Sapolsky describes the neurochemical and neuroanatomical changes that arise as a result of depression.  It’s unsurprisingly quite technical…
• Personality, temperament and stress – much of the popular understanding of stress is coloured by the studies that were done on baboons.  Studies on baboons have shown that more driven, ambitious but less sociable animals are much more likely to suffer stress-related diseases than animals with a more consensual role in the group.
• The view from the bottom – if Sapolsky redeems his cholesterol-hypothesis errors in my eyes, he does it in this substantial chapter, where he goes over similar ground to Michael Marmot in describing how social stress is directly correlated to life expectancy.

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So what do you think?

Overall, this is a good book to have on the shelf.  I wouldn’t try reading it all the way through in one go like I did.  It’s too rambling and wordy to really force all of the detail into your head in a short period of time.

Also, while Sapolsky is an enthusiastic narrator, he often sounds like Mr Blue in the Edward Norton Incredible Hulk film.  He rattles along at a hundred miles an hour and stuffs his dialogue full of caveats.  This is endearing to start with but it gets a little tiring after a while.  You start to feel the itch to smack him about the head to demand a few bullet points instead of three pages of stream-of-conciousness monologue.

More irritating than this, however, is that Sapolsky’s general understanding of health is outdated and poorly thought through.  He seems to believe that endurance running, vegetarian diets and low cholesterol are good for your health.  This has more of an impact on the health sections of the book than you might expect and it’s certainly disappointing.

However, Sapolsky covers a huge range of the literature and does so with the experience of the expert who has been working in the field for a very long time.  As a reference work that starts at the level of the intelligent lay-person, this book is unsurpassed and a worthwhile addition to any library.

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In summary: buy this for your bookshelf, not for your summer holiday.