Alanna Collen’s 10% Human Book Review

As one of our Symprove book club recommendations, we have been reading Alanna Collen’s 10% Human. Thank you to those of you who read along with us. We certainly felt we learnt a little more about microbes and how they influence our bodies, hope you did too.

During the course of the book, Alanna (and so by extension us too!), learns more about advances in modern medicine such as hygiene and vaccination, our propensity for allergies and autoimmune health conditions, as well as the links between obesity and the gut.

Alanna gives the reader three great takeaways from the book – things which can strongly influence our microbiomes – one is diet (eat more plants!), one is only using antibiotics when necessary, and the other is to educate ourselves on the particular influences on babies’ microbiomes to arm them for their own healthy futures.

This book gave a real insight into how microbes are crucial to our systems and firmly reminded us that the responsibility for our own microbiome lies within our power: ‘the microbes you are home to, unlike the genes your parents bestowed on your or the infections your environment exposes you to, become yours to shape, cultivate and care for.’

Of course, the book also raised quite a few interesting questions and we got our readers to pose some which Alanna kindly answered for us. Read on to find out the five questions we asked Alanna and her responses…..

1. Since you wrote the book, what else have you learnt about microbes and gut health?

I began work on 10% Human after an appointment with my doctor, where I had suggested, with great naivety at that stage, that my ’good bacteria’ had been damaged by the antibiotics I’d taken. He was utterly dismissive, telling me that any such ideas were left-field nonsense. That was in 2013. I went home, disappointed and surprised, and immediately began looking in the top science journals for information about ‘good bacteria’.

I discovered that there was a burgeoning field of microbiome science, one that was generating cover stories in Science and Nature. It was making links between the gut microbiome and all sorts of health problems, linked primarily through the immune system. I was hooked, and 10% Human was born.

The majority of my book was written in 2014, when there was an absolute explosion of research into the microbiome. But at that time, many of the links between microbes and health were hypotheses and ideas, with not much evidence to support them, other than logic. I left a great many potential connections out of my book, because it was crucial to me that the evidence spoke for itself.

So in the five years since 10% Human was published, I have learnt a great deal more. It’s been gratifying to see many hypotheses supported with new evidence – connections between microbes and dementia, Parkinson’s disease, migraines, and cancer, for example. The link between mental health and the gut microbiome has been strengthened, and our understanding of the role of inflammation in health is much better now.

One thing that has stood out has been the extraordinary complexity of the role of individual strains of microbes, and their interactions. Questions like ‘can supplementary bacteria (probiotics) impact health?’ have become obsolete. Instead, people are asking ‘Which strains help what conditions, and why?’ Scientists are increasingly recognising the degree of personalisation our microbiomes contain, and how different our dietary needs can be.

2. What do you do to help your own gut health?

I take a very holistic approach to my own gut health. I’m often asked what my ‘top supplement’ is, or ‘what fibre source should everyone being taking?’. Even ‘which is the best vegetable?’! But I don’t think it’s necessary to be so specific. I follow a Mediterranean-style diet, which is high in plant foods, and fibre, including lots of grains and lentils. But I’m not over-zealous about it – I do eat plenty of foods that wouldn’t be considered healthy from time to time, because I enjoy them! I do take a daily probiotic. I exercise (even if only for five minutes a day up and down the stairs) as that reduces inflammation, and I eat some probiotic foods, such as yogurt. For me, the high-fibre, high-plant foods diet is the most important element of taking care of my gut microbes.

I also avoid taking antibiotics where possible. I make these decisions in conjunction with my doctor, by asking her what the risks are of not taking antibiotics, and how likely it is that an infection will go away on its own. It’s about avoiding unnecessary antibiotics, not about shunning them altogether – they are life-saving drugs and sometimes they are essential. When I do need antibiotics, I take additional probiotics throughout and for some time afterwards.

3. Is gut health linked to mental health?

Gut health and mental health are strongly connected. It’s always the element of the gut microbiome story that surprises people most! For too long there’s been this idea that the brain and the body are somehow separate, and that mental health problems stem from a poor attitude, or external events only. I don’t buy that at all. The brain is as much a part of the body as any other organ, and its biochemistry is affected not only by external events such as what’s going on in our lives, as by internal factors such as what we eat, the physical activity we do, and, perhaps most importantly, the degree of inflammation our immune system is producing.

Every emotion we feel, every thought we think, and every decision we make is underpinned by electricity and chemicals in our brains. Whatever the outside source of an emotion, a thought, or a decision, it can only come about through electricity and chemistry in our brains. And so of course, the conditions in our bodies can impact our feelings and our behaviour.

There are multiple ways that the gut microbiome plays into this. The most important is likely to be the degree of inflammation in our bodies. Inflammation is what happens when the immune system is triggered. It releases specialised cells and chemicals that affect how our brain cells behave, how connections are made, and what neurotransmitters and hormones are released. Having a healthy gut microbiome is a key part of reducing chronic inflammation and protecting the brain from it.

Another significant connection between the gut microbiome and the brain is via the vagus nerve. This is a major nerve that runs from the brain to several organs, including the gut. Its purpose is to keep the brain informed about what’s happening around the body. It feeds back information from the gut about what foods have been eaten, which helps the brain to regulate appetite. It also transmits chemicals which makes us happy, and many of these chemicals come from microbes that have processed the fibre in our diets.

4. How do you look after your children’s gut health?

In 10% Human I wrote about the role of natural birth and breastfeeding for children’s gut health. At that time I did not have any children of my own, but the research I did for the book profoundly influenced my understanding of the importance of gut health for babies and children.

When I was pregnant with my daughter, who is now three, I was very keen to have a natural birth and to breastfeed her for as long as I could. I even chose to have a home birth to increase the odds of this happening! I was fortunate that everything went smoothly and I did have a natural birth for my daughter, but I had serious problems making milk as I had retained placenta after her birth. I worked extremely hard to keep breastfeeding for 15 months, but I did have to supplement with donated breastmilk and formula milk in the early months, as my supply was not meeting my daughter’s needs. It was very difficult, but I was absolutely determined, given what I knew about gut microbes and breastfeeding!

Of course, I avoid giving antibiotics to my daughter where possible. As yet, she has not had any, although I have twice picked some up for her on the agreement with my doctor that I would use them if her symptoms worsened over the weekend. I would absolutely give her antibiotics if the doctor told me it was necessary.

I also try to give my daughter a high-fibre, high-plant content diet. It’s difficult at times with a fussy pre-schooler, but on the whole we manage a decent, if a little limited, diet. I give her probiotics if she has loose stools or seems constipated.

5. What things affect our immune systems?

Our immune systems are so much more fundamental to the way our bodies function than we’ve ever really appreciated before. The most obvious function is to attack pathogens and protect us from illness. But the immune system plays a much more generalised role as a kind of clean-up team. It clears away cells that have died or malfunctioned, including those that could become cancer. It prunes synapses in the brain in childhood (and beyond) so that only those we need remain. It helps in memory formation and in many other systems of the body.

As for what affects it… Well, a lot of things! There’s constant communication between our gut microbes and the immune system, most of which is situated in the gut. Gut microbes are involved in ‘training’ the immune system to recognise what’s harmful and what’s safe, so that it knows not to react to a piece of carrot, but that a pathogenic microbe (let’s say E.coli 0157, for example) is dangerous and needs to be dealt with. The immune system also learns to tolerate the body’s own healthy cells and innocuous particles like pollen. But when something has gone wrong in its training, it might attack body cells (creating an autoimmune disease) or innocuous particles (creating an allergy).

The immune system is primed largely in childhood, by exposure to beneficial microbes, to infections, to foods and particular vitamins, and probably also to environmental chemicals and pollution. It can continue to be affected by all these things later in life as well, with many autoimmune diseases cropping up in adulthood, particularly among women in their thirties. Having a healthy high-fibre diet, getting enough vitamin D, and avoiding food poisoning are all important in supporting the microbiome and the immune system.

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