Gut, by Gulia Enders, a book review

Gut, The Inside Story of the Body's Most Underrated Organ -- a Book Review by Ruth Baigent

​In 2002, gene sequencing technology enabled science to identify microbes according to their genetic blueprint. This lifted the restriction on identifying microbes by culturing them on a Petri dish. Bacteria can now be identified dead from their DNA – for instance in the human stool.

Most gut bacteria do not bloom away from their native anaerobic environment and cannot be examined and identified by the old methods, so we are still ignorant of more than 60% of gut bacteria. (p236) Identification by genetic blueprint has enabled medical science to move into bacteria-related digestive health research in a big way. An explosion of new research (much of it seemingly using mice) has led the world of medicine to some dramatic re-thinkings on the role of bacteria in our lives: “we are gradually decoding processes which we used to believe were part of our inescapable destiny”, says Enders.(p204)

Over the last couple of years, there has been a proliferation of books like Gut which tend to be research led and written by fascinated and enthusiastic biologists and medical research doctors thriving on the possibilities for understanding that new research is enabling. Ten years ago, scientists tended to think that all humans had the same bacteria in their systems. New tests show us that this is far from true: our digestive systems are populated by billions of bacteria, 1000+ species, “plus minority populations of viruses and yeasts, as well as fungi and various other single celled organisms”(p140) which are uniquely our own.[i]

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In Gut, Gulia Enders aims to use her information processing powers to feed back, to general readership, recent scientific studies into bacteria and the human microbiome.[ii] She wants to pass on beneficial and life-changing ideas (p104) and “show, in an entertaining way, why the gut is so fascinating, what exciting new research is currently underway and how we can use this new knowledge to improve our daily lives.” (p4)

Enders starts the book with an introduction to the digestive system - from eyes to anus - and its related health and medicine. She names, from the medical point of view, a transition from conscious to unconscious - which Enders places slightly further up the body than Kathrin Strauffer [iii] (Anatomy & Physiology for Psychotherapists: Connecting Body & Soul). Enders says, “The unconscious inner world begins at the level of that small hollow you can feel at the top of your breastbone. From there on, the oesophagus is made of smooth muscle.” (p4) Smooth muscle is the muscle not under our conscious control.

I felt there was a fair bit of new information in this section of the book, including some matters interesting to us as biodynamic massage practitioners working with the digestion and peristalsis.

For instance, it was interesting to read Enders' description of the stomach, and the process of “retropulsion”, where the stomach literals shakes until any food inside it is broken down into pieces of - on the whole - less than 0.2cm. This takes 2 hours for easy food like cake, and 6 hours for proteins like meat. (pp80-81)

About left side lying, we lie clients on their left side at the end of the session to keep the stomach in a naturally closed position, and to allow for completion of any movement of food down into the digestive system. Enders notes that if you have a bloated stomach, this can be relieved by lying on the left side. It will encourage burps. (pp30-32)

Enders talks about the “migrating motor complex” (MMC), a peristaltic “housekeeping” mechanism for the stomach and small intestine, which, according to sources such as Wikipedia,[iv] kicks in after 90-120 minutes of not eating. She says that the “little 'housekeeper'”, MMC, looks “cute [when] observed with a camera”.(p83)  But sadly, I was unable to find any videos online to link to. It is the MMC that causes tummy rumblings, “[not] when we're hungry, but when there is a long-enough break between meals to finally get some cleaning done”. (Ibid) The amount of noise it makes, Enders says, depends on how much air is in the stomach and small intestine. [Edit: Since this was first published, a video is now available online and I shall link to it below:]

I am not clear – even after further research on the internet – exactly what relation the MMC bears to other peristalsis - ie, to the mechanism that moves a food 'bolus' down our gastrointestinal tract when we eat. 

It was interesting to read in Gut about the physical/mental crossover in digestion. For instance, Enders describes Roemheld Syndrome. With this syndrome, gas builds up in the stomach to such an extent that it presses on the heart and vagus nerve. This can cause dizziness and anxiety, difficulty breathing, or severe chest pain. (p32)

Enders talks, also, about the small intestine working best when we are “pleasantly relaxed” and ”the blood is not full of stress hormones” taking energy from the digestive process. The part of the brain responsible for tiredness is stimulated after eating, which continues until digestion is well under way and energy resources from the meal have been released to us in the small intestine. (pp38-39) 

We find out that digestion is finessed in the large intestine, where armies of bacteria will, for periods of something like 16 hours, mull over contents, digesting, and producing important vitamins and minerals like calcium as their by-product. This is where the vast majority of gut bacteria live, many of whom – a kind of reserve - will be housed - safe from loss by diarrhoea - in the haven of the appendix. Everything absorbed from the intestines will be filtered by the liver, except when it comes from the last section of the large intestine.[v] Anything absorbed from here will go straight to the bloodstream – which is why suppositories are so effective. Suppository drug dosages are low because processing by the liver leads to variable (but high) proportions of a dose being treated as toxins. Hard work for the liver. (pp41-43) 

Enders offers us a first batch of useful dietary advice at this point in the book. She talks about sugar,(p45) and in particular, fructose, as being especially problematic for our systems, in terms of intolerances [vi] and weight gain. (As a point of interest, excess sugar is stored in reserves in the body 1. as glycogen – in the liver – and 2. as fat – in fatty tissue. Glycogen reserves get used up first. It is more tiring to use fat stores, so exercise feels like harder work when you do enough of it to get through to the valuable resource of the fat.[pp45-46]) There is research underway into gut bacteria and obesity. The link between bacteria and sugar, and digestive problems is known: excess sugar consumption encourages growths of pathogen bacteria – like those that feed on our teeth and cause tooth decay. There are many good reasons to avoid sugar. More on this below.

Fat entering our bodies is digested and transported via the lymphatic system straight to our heart. It is not processed for toxins by the liver (p47) so “our heart and our blood vessels are at the mercy of everything that McDonald's and similar chains have been able to get hold of at the lowest purchase price.” (p49)

Enders says, we should keep beneficial household fine oils - such as cold pressed olive oil - well sealed and in the fridge to protect from free radicals attaching themselves to the fat molecules. We should cook with solid fats, such as butter and coconut oil, which will not be adversely affected by heating.(p50)

Interestingly, vegetable fats are pain reducers. They contain more of the anti-inflammatory substance alpha-linolenic acid, and olive oil contains oleocanthal, both of which work in a pain reducing way, similar to ibuprofen or aspirin. Whereas arachidonic acid in animal fats is “converted in our bodies into neurotransmitters involved in the sensation of pain”.(Ibid)

Tips like this can help us go easy on our systems, especially when they are having a hard time coping – as will be the case with many of our clients. A person in “normal health” will not be too adversely affected by occasional excesses, Enders says.

A more vegetarian diet needs to include enough “complete proteins”. These are available in quinoa, tofu, amaranth, spirulina, buck wheat and chia seeds, or in combinations of certain foods such as peanut butter on toast, pasta with cheese, humous and pitta, rice and beans.(p52) If there isn't already an app out there to help with this, I think there should be!

After breaking down some of the complex areas of the digestive system, Enders gives us an overview of medical responses to problems that arise. She discusses reflux, vomiting and nausea, and constipation. I was interested to read her descriptions of medical drugs for digestion: for instance, that laxatives come in four different types, each with a very different way of working.[vii] And there was discussion here about the “gut-brain” and gut-related mental health. 

​Enders talks of the power of the gut, “a huge matrix, sensing our inner life and working on the subconscious mind”(pp120-121) which develops “in parallel” to our head brain. Enders advises that we should ensure for our children calm meal times, to avoid developing a digestive system habitualised to stress.(p107) Discussing depression, Enders says that the gut manufactures 95% of the serotonin we produce, and “perhaps [the] gut needs a session on the therapist's couch, and [the] head is not to blame at all.”(p130) Enter, biodynamic massage and bodywork Psychotherapy! “We humans have known since time immemorial something that science is only now discovering: our gut feeling is responsible in no small measure for how we feel.”(p116) These sections are well worth digging into.

From https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.999001/full

A couple of years ago, I read another fascinating and practical book about digestion: “Constipation, Withholding, and Your Child” by Anthony Cohn.[viii] I highly recommend this book written by a seasoned professional in his field, and would like to draw on what he says, here, for the benefit of biodynamic practitioners, to round off our understanding, and to offer some background about the onset of digestive problems which happen early in life.

Cohn starts his book with a brilliant story for children about “Mr Poo” who wants to come out and play with his friends in the toilet, and gets very grumpy when you say “not now, Mr Poo!” This book goes on to describe the “lifecycle of the stool” in much the same way as Enders - with particularly helpful diagrams. Cohn talks about digestive problems starting as early as the first solid poo.[ix] This first poo can be painful, and a child may try to avoid that pain by trying not to poo. This “withholding” is both a big effort for the child, and also means that the stool collecting in the bowel becomes larger and harder as the large intestine saps it of fluid. So it will become harder to pass.(Cohn p17) This “reinforces the idea that pooing is painful and is to be avoided at all costs: very quickly a vicious cycle is established.”(Cohn p22) Cohn says “Stool withholding is a protective 'reflex' to prevent pain”(Cohn p24) which can give rise to eating disorders. 

In my opinion working with, and observing children, as well as adults, this starting point can lead to lifelong disorders if the issues are never addressed calmly and sensitively – and most of all, effectively – by well resourced parents / carers. It is quite mind blowing to go back in time, and find the source of the problem in such early moments of life. Incidentally, part of Cohn's treatment is to recommend a course, or courses of laxatives, as a resource for making a softer, less fearful stool. 

Moving into the second – largest, and most complex - part of Gut, Enders focuses on bacteria and the microbiome. Here, we are offered an insight into the ecosystem of the gut which I intuitively interpret as being like managing a compost bin or wormery: keep it in balance with the correct levels of kitchen and garden waste - 50% greens, 50% browns, and so on – and you'll have a thriving, healthy ecosystem. Lose the balance, and you'll get flies, mould and slime...!

Well, the microbes in our digestive systems do something similar, and here “slime” equates to all sorts of problems – within and outside of the gut. “Skewed proportions of the different bacteria in our gut have been detected in those suffering from obesity, malnutrition nervous diseases, depression, and chronic digestive problems.”(p138)

There is nowhere on Earth that is uninhabited by bacteria, and with their speedy reproduction (about every 12 minutes) and with 4 billion years of evolution behind them, bacterial development is varied, and their powers are pretty incredible, as we shall see.

In the human being, 90% of our cells are bacterial, and the majority of those live in our gut. These bacteria are incredibly useful to us: “some scientists now support the theory that our gut microbiota can be considered an organ”.(p182) Because of the scale of the bacterial kingdom, and, until recently, major technological limitations, much is unknown. For instance, some bacteria which are associated with negative conditions, and routinely attacked with antibiotics, have recently been discovered to have other beneficial effects, for example, Helicobacter pylori.[x]

To give a sense of how pervasive and powerful bacteria are, recent studies show that personality characteristics appear to be alterable with alterations in gut bacteria (pp126-127) - in research on mice, mouse personalities changed from from “timid” to “gregarious” as bacteria were swapped between them. “The first study of the effect of intestinal care on healthy human brains was published in 2013 – two years after the study on mice. … After four weeks of taking a cocktail of certain bacteria, some of the areas of the subjects' brains were unmistakably altered, especially the areas responsible for processing emotions and pain.”(p121)

Gut bacteria might also cause changes in host appetite – theoretically being able to affect our choices about tastes, desires and satiety. Remember the wildlife documentary where a parasite took over the brain of a snail, giving rise to suicidal behaviour in its host? There are many studies of such things.(pp196-204) Enders points out that over our 3 million years together, it is reasonable to expect that bacteria have learned to exert influence over us for their own survival. One avenue for influence is the ability bacteria have to send the amino acids tyrosine and tryphophan to the brain which are there converted into dopamine and serotonin in brain cells.(p177)

Bacterial influence over some aspects of physical health have also been studied. Healthy mice given bacteria from a mouse with type 2 diabetes will develop problems metabolising sugar. And mice kept in a germ free environment and given bacteria from an obese human will increase their likelihood of gaining weight.(p146) Gut bacteria are responsible for blood groups[xi] and harmful bacteria cause diarrhoea.(p138) 

Conditions that may be treated by bacteria currently include allergies, flatulence, diarrhoea, lactose intolerance, obesity, inflammatory joint disease, diabetes, and immune system conditions generally.(pp231-233) Pain reduction can be achieved by changes in gut bacteria.[xii] There is a soil based bacteria which has been found to have anti-depressant qualities.[xiii]

The question of how we develop and maintain our gut flora is a big one. 

A normal birth starts us off nicely as we are “wrapped protectively by a useful coating of bacteria… mainly our mother's vaginal and gut flora, mixed with a few skin-dwelling germs, and possibly a few others from the hospital's repertoire.”(p149) Enders says that there is general acceptance amongst scientists, now, that “the first populations to colonise our gut” - within the first three weeks, even - will “lay the main foundations for the future of our entire body.”(pp152-153)

Breastmilk fills in all the particular needs of the human child: it “contains everything, knows everything, and can do everything necessary for a child's wellbeing.”(p151) At about 3 years of age, with lots of kisses and cuddles along the way, “the gut flora develop to the right level and then stabilise”.(p150)

Normal patterns have been altered on a big scale in the advent of antibiotics: their overuse in medicine, and in the meat and dairy industries. We also over use anti-bacterial and other heavy duty cleaning products in the home. We have had a massive rise in birth by caesarian section (1/3 of western babies) and a reduction of full or even partial term breast feeding, and an increase in hospital births.

When it comes to bacteria, cleaning carries risks. Have you ever noticed yourself become more smelly after a shower? If you wash off the protective fatty layer on your skin, the natural bacteria are eliminated and odour-producing bacteria are given a “better foothold”.[ix]

A newborn baby has plenty of these “footholds” if he or she hasn't been through the mother's birth canal. “Three-quarters of new born babies who pick up typical hospital germs are those born by caesarian section” and C-section children take months, or longer to develop a normal population of gut bacteria.(p153) And from what I have read, I have to ask “will they ever?”

So much of what Enders states, and what I have read elsewhere, suggests that once the early chances of healthy development have been missed, and the microbiome has stabilised, it is going to be extremely difficult to undo any loss to the rich diversity we require.[x] We can't pick and chose the bacteria we want, because, even if they are available to us, it is difficult to get them situated. It is almost impossible for new bacteria to get past the acid of the stomach. Then they have to survive all the way along the small intestine and down to the bottom end of the large intestine, where they live in greatest number. Once they get there, they need to find a foothold – with rival bacteria potentially attacking, for instance, with a spray of their own antibiotic defence product. Finally, they have to like their new abode.(p152) Shop bought probiotic products may not be the sort to take up home in the gut, and may simply have to be taken regularly for beneficial effect. Also, they will be limited to a few strains, when our natural diversity includes over 1000 species, all of which tend to support each other.

“Stool Transplant”[xi] seems to meet some of the problems. It works by introducing teams of bacteria strains from the gut of a “healthy” donor into a recipient gut. It's early days. The transplant stool is purified, but is not pure, and it is not clear what else might be transported with the transplant. The procedure is used with caution, and only for those in dire need – for instance, those with an antibiotic resistant Clostridium difficile infection.

Enders talks of bacteria that are passed only from our ancestors - such as  bacteria which have an ability to digest seaweed, and are common to the Japanese people. Since we live in a germ-free environment until we are born, this inheritance must come from the birth canal and physical contact after birth. Loss of such bacteria means loss of abilities – such as digesting seaweed. Bacteria also determine how much energy and beneficial effects we get from what we eat.(p161)

Losing our natural inheritance is obviously very worrying as we start to realise that there are practices in place which are dangerous and/or life changing to the human race. Antibiotic resistant pathogens are a huge and terrifying problem - old killers such as TB are making a return, and new breeds, such as Clostridium difficile and MRSA are emerging.

Some of these will be out of our control, but for those of us suffering problems, how can we develop the diversity of our gut flora and make ourselves more healthy? Doctors are studying complex ecosystems within other complex ecosystems, interacting with still other complex ecosystems: all uniquely complex. And it's all very new. Hence, there is a lack of research, and lack of help available from Doctors in your local surgery.

Enders offers some general advice: don’t go after the bad guys, seek to create fertile ground for the good guys to flourish in. We need a few pathogens to keep our immune system on its toes, that's how it works – both inside our bodies, and in our daily environment. The natural balance serves us well. When we clean, unless there is an infection, it is sensible to aim only to reduce, not eliminate, bacteria, 95% of whom are harmless, and many of those beneficial. We want the bacteria to be present enough to re-populate in balance, because this balance protects us from infections of harmful bacteria.(p212)

We can take probiotics, and we can make dietary changes to support our beneficial bacteria – excluding overindulgence in foods that are preferable to pathogen bacteria, and increasing the amount of food known as prebiotics, which support the healthy diversity of bacteria already present.

Probiotic products are selected breeds of bacteria delivered in powder or capsules, or in things like live yogurt or fermented food. Enders says “try out different products for yourself [each over a period of about four weeks], until you hit upon a bacterium that seems to help.”(p233)

In terms of prebiotics, bacteria prefer food that we cannot digest easily and that goes straight down to the large intestine undigested.(p177) However, we don’t want to end up with too much of the wrong sort of bacteria food - undigested meat, for instance. The toxins produced from the type of bacteria who like to eat undigested meat can even lead to cancer.(p241)

Avoid household sugar – the type that tooth decay bacteria love. Eating too much sugar encourages “chubby bacteria”(p174) - these are bacteria more attracted to chocolate than plants, and whose by-product is fatty acids that feed the liver and gut, rather than feeding the rest of the body. Inulin is a completely healthy sugar which appears in products labelled “sugar free” or “fat free”.(p242)

Prebiotic foods includes vegetables from the lily family: eg, leeks, asparagus, onions and garlic; Compositae-plants: eg, endives, sasify, artichokes and Jerusalem artichokes; resistant starches such as potatoes or rice which have been boiled and left to cool; and high fibre foods such as wholegrain wheat, rye, and oats. High fibre foods should be increased slowly, so as not to overwhelm underfed bacteria (remember the wormery?).(pp238-239)

Gut has widened my perspective on some fascinating science, and offered insight into the complexity of medical research, which is necessary to gain deeper understanding. At the same time, attempting to grasp some of the details of the new bacterial science is clearly a difficult prospect right now. With GPs unable to prescribe or advise,[xii] we must rely on help from books and the internet to inform us and develop our own wisdom. We can take suggestions, and do our best to find answers for ourselves by trial and error. 

There are no easy answers, but there is space to learn, and the benefits of getting it right include mood enhancement, longevity, digestive health, and physical well being.

Footnotes:
All other page references are from ENDERS, Gulia. (2014) Gut, London: Scribe Publications.

[i] Our own unique “bacterial fingerprint” complete with all sorts of surprising and outlandish things we have picked up or inherited. (p158)

[ii] A couple of useful definitions:  - Microbiota: all the micro organisms in a particular environment - eg, our gut.
 - Microbiome: all the microbes and all their genes combined.
From Prof. Simon Carding, Leader of the Gut Health and Food Safety Research Programme, Institute of Food Research and  Norwich Medical School at the University of East Anglia. 
CARDING, Simon. (2015) Gut bacteria and mind control: to fix your brain, fix your gut!, [Online] Available: www.youtube.com/watch?v=mioR_WrkRaU [20 Oct 2015] (Video available to watch below)

[iii] “The pylorus, meaning gatekeeper … a gatekeeper to my unconscious.” P 121. STAUFFER, Kathrin. (2010) Anatomy and Physiology for Psychotherapists, London:  Norton.

[iv] WIKIPEDIA. (2015) Migrating motor complex, [Online], Available: en.wikipedia.org/wiki/Migrating_motor_complex [20 Oct 2015]

[v] Although Enders later seems to be excluding fats from this, see p47

[vi] pp53–62 “Wheat products for breakfast, lunch, and dinner; fructose in practically all processed foods; or milk products long after weaning – it is not surprising that our bodies sometimes rebel.” p61

[vii] Osmosis, slippery stool, hydragogues, and prokinetics. pp107-113

[viii] COHN, Anthony. (2007) Constipation, Withholding, and Your Child, London:  Athenaeum Press. (First few pages available here: books.google.co.uk/books?id=VvJbVJ3wjz8C&pg=PA13&lpg=PA13&dq=mr+poo+and+little+miss+wee&source=bl&ots=pnCopx6s68&sig=Ou_yDAXe27IbnW0uY-770XCh-QY&hl=en&sa=X&ved=0CB0Q6AEwAWoVChMIpfh_4uVyAIVA88UCh0WIwlB#v=onepage&q=mr%20poo%20and%20little%20miss%20wee&f=false )

[ix] There is rarely an underlying physical cause such as disease. COHN: p28. The starting points tend to be “the first few days of life, weaning, febrile illnesses, toilet training and starting school” COHN: p25

[x] Helicobacter pylori is linked  to stomach cancer, Parkinsons and stomach ulcers, but lowers risk of lung cancer, stroke, childhood asthma and eczema. pp191 – 195. Sadly, before it was realised that H. pylori was a normal part of our gut bacteria, medicine had been trying to eliminate H. pylori with antibiotics for many years.     Also, see BLASER, Martin. (2014) Missing Microbes, London: Oneworld Publications. pp9-10

[xi] Only once babies develop their own immune system do their blood types kick in. p143

[xii] In particular, Lactobacillus plantarum and Bifidobacterium infantis have pain killing attributes. p128

[xiii] Mycobacterium vaccae which has been shown to act as an antidepressant. “Microbes in soil are also being investigated for improving cognitive function, Crohn’s disease and even rheumatoid arthritis.”     GRANT, Bonnie. (2015)  Antidepressant Microbes In Soil: How Dirt Makes You Happy, [Online], Available: http://www.manchester.ac.uk/discover/news/article/?id=12760 [20 Oct 2015]

[ix] p216. Which leads to some pretty interesting ideas. A bacteria deodorant, for instance. Enders says there are bacteria working cleaning public toilets in Düren, Germany! p217. This reminded me of a friend who, as a PhD student over 10 years ago, was researching a nuclear waste-eating fungi that could secrete oxalic acid to de-contaminate it. These kinds of projects continue: 
    BREWIN, Katie. (2014) Scientists discover hazardous waste-eating bacteria, [Online], Available: http://www.manchester.ac.uk/discover/news/article/?id=12760 [20 Oct 2015]

[x] We are made up of diverse ecosystems like a coral reef or a tropical jungle. And the diversity is crucial because “High diversity affords protection to all species within the system because their interactions create robust webs for capturing and circulating resources.” BLASER: p24.

[xi] pp235-236  
    Wikipedia’s page on fecal microbiota transplant (FMT) says the procedure is "infusion of stool, e.g. by enema, orogastric tube or orally in the form of a capsule containing freeze-dried material”. It also says that research is underway for treatment with “other gastrointestinal diseases, including colitis, constipation, irritable bowel syndrome, and neurological conditions such as multiple sclerosis and Parkinson's.” These are amongst the conditions that Enders has detailed as potentially benefiting from treatment with bacteria. 
    WIKIPEDIA. (2015) Fecal Bacteriotherapy, [Online] Available: 
    https://en.m.wikipedia.org/wiki/Fecal_bacteriotherapy [20 Oct 2015]

[xii] NHS CHOICES. (2014) Probiotics, [Online] Available: http://www.nhs.uk/Conditions/probiotics/Pages/Introduction.aspx [20 Oct 2015]



Reviewed for the Biodynamic Massage Journal by Ruth Baigent and first published there, Volume 17 Issue 2, Autumn 2015