<b>Mitali Saran:</b> Ten per cent human

There's a reason we talk about having 'a gut feel'

On a recent flight, the man next to me drank six glasses of wine and then asked if he could read my book. I was watching a movie when he asked, so there wasn’t a good reason to say no. Books broaden one’s horizons, even if one is already seeing multiple horizons. It would have been mean-spirited to refuse. But I couldn’t help being irritated, and the trouble with lending a book resentfully is that one is plagued with trust issues. I spent ten minutes spying on him while he thumbed repeatedly and exclusively through the contents, sometimes pursing his lips, sometimes holding his head and blowing out of his nostrils like a horse. Then his meal arrived, and he plunged his right hand into daal while continuing to paw my book with his left hand. This was the last straw.

I popped the headphones out of my ears. “What are you doing?” I said coldly. He looked up through his eyelashes, a la Princess Di. “This is a very surprising book,” he said, and then leaned across the empty seat between us and bellowed, “Who ARE you?” into my face. That’s irrelevant, I snapped. “Well I think this book is irrelevant,” he said, as if this was a brilliant comeback. I reached across and snatched it back. “Read your own book,” I said, as if this was a brilliant comeback. Thus our acquaintance took root, flared briefly, and passed away, unmourned.

The larger point, here, is that I advise you to throw on some clothes, lace up your shoes, and grab your phone to order this book at once. It’s called Gut, by Giulia Enders, and it features chapters like ‘How does pooing work?’ and illustrations of bacteria with smiley faces and capes. If you, like me, are irresistibly drawn to accessibly written books about science, you will thank me, as I thank my friend Martin who pointed me to this one.

I have written about bowel movements in the op-ed pages of this long-suffering newspaper, so it’s not as if my interest in potty is a secret. What is truly baffling to me is why so many other people, barring Bengalis, aren’t as interested, considering that it’s a daily affair that can make you miserable when it goes wrong. But whatever—life is short, miss out if you want to. At any rate, poop is only one angle of that thrilling young field of research, the human microbiome.

For those unfamiliar with the term, the microbiome refers to the unimaginably large numbers of bacteria that have co-evolved to live all over the human body to, mostly, preserve and defend it. If that creeps you out, you might want to digest this: In the womb, you are composed of 100 percent human cells; by the time your microbiome stabilises around the age of three, only about 10 percent of your cells are human. The other 90  percent are bacteria. They began to colonise you the moment you exited your amniotic sac. In the normal course of events you emerge into the world with a protective coating of your mother’s vaginal flora, and go from there, picking up and breeding billions of bugs a minute. About 2-3 kilos of bacteria, or about 99 per cent of all your critters, live in your gut, and comprise a large part of your immune system, and what scientists are calling your second brain.

It’s all completely fascinating, and Giulia Enders makes you laugh even as she blows your mind. Do yourself a favour and read it. Just please don’t read it with your hands dipped in daal.