Something I’ve Been Telling You For Years About The Gut Microbiome May Be Wrong

Science calls…

Suppose I had admonished you over these years that the science is settled, that there appears to be consensus, and that those who raise questions that put us steps or miles back are deniers…peddlers of junk and pseudo science.

You might think me lazy, and you would be right. That’s why I’m right about the little Sunday-school, catechism children of the Christopher Hitchens Appreciation Group on Facebook. Pathetic; a Disgrace to Christopher Hitchens are they—now causing him to be rolling in his grave when he should be resting in peace.

How many times have you heard that there’s 10 times as many bacteria in our guts than cells in our body, here? Dozens, at least. Hundreds and thousands if you account for other sources. That was the science. It was also the science for over 100 ears that babies are born with sterile guts. I still see that peddled about, but I put this in Chapter 1 of “The Gut Bug Book,” yet to come, about 2 years ago:

Where do your gut bugs come from? From 1900 until very recently, it’s been held as dogma that human infants are born with sterile guts, and only begin acquiring microbes during the trip down the birth canal and subsequently, through breastfeeding and human contact. However, we now know that’s not the case (even though you still encounter the myth frequently) and fetuses are seeded with gut bacteria while still in the womb.[6]

[6] “Mom Knows Best: The Universality of Maternal Microbial Transmission.” 2013. 9 Feb. 2014 <>

So much for “settled” and “consensus” science over more than 100 years, until someone bothered to take a new look.

So here’s the new science:

Scientists bust myth that our bodies have more bacteria than human cells

It’s often said that the bacteria and other microbes in our body outnumber our own cells by about ten to one. That’s a myth that should be forgotten, say researchers in Israel and Canada. The ratio between resident microbes and human cells is more likely to be one-to-one, they calculate.

A ‘reference man’ (one who is 70 kilograms, 20–30 years old and 1.7 metres tall) contains on average about 30 trillion human cells and 39 trillion bacteria, say Ron Milo and Ron Sender at the Weizmann Institute of Science in Rehovot, Israel, and Shai Fuchs at the Hospital for Sick Children in Toronto, Canada.

Those numbers are approximate — another person might have half as many or twice as many bacteria, for example — but far from the 10:1 ratio commonly assumed.

How the settled consensus came to be for alomst 45 years ought to be instructive for little children going to Sunday school for catechism everywhere. So how did this 45-years of science dogma that everyone simply assumed was true, happen and perpetuate to where thousands of scientists were saying it?

The 10:1 myth persisted from a 1972 estimate by microbiologist Thomas Luckey, which was “elegantly performed, yet was probably never meant to be widely quoted decades later”, say the paper’s authors. In 2014, molecular biologist Judah Rosner at the US National Institutes of Health at Bethesda, expressed his doubts about the 10:1 claim, noting that there were very few good estimates for the numbers of human and microbial cells in the body.

Well, little children usually do grow up some day, and put away childish things.

…In terms of the book, don’t ask. Now I literally have to go through it again, word for word, 400 pages, roughly, to account for new science. I’m glad I wasn’t enthusiastic about publishing quick (truth: just excusing my laziness). Don’t care about the money. Tim and I have a gentleman’s understanding of how it works if it does make money.

Finally, this is not particularly important and I never took it as such. I did, however, gleefully use it whenever I could for the simple (and I think essentially harmless) reason of emphasizing the importance of the human gut in understanding all human biology going forward.

It’s not like I was trying to get you to obliterate the entire world economy over it, like Sunday school children reading their catechisms would like you to do over average world temperature graphs. Graphs, which, ironically, suffer a similar error or relative proportion and importance.

It’s funny. In the world were everything is an error on some level, and you attempt to be a little less erring over time, it’s intuitive that it ought to be more prudent to under error than over error.

But in the realm of grant whoreing, cushy jobs, and private-jetting around the world to attend conferences, under-error won’t even get you a position at any of these conferences serving hors d’oeuvres in a shabby server’s tux.

Richard Nikoley

I'm Richard Nikoley. Free The Animal began in 2003 and as of 2021, contains 5,000 posts. I blog what I wish...from health, diet, and food to travel and lifestyle; to politics, social antagonism, expat-living location and time independent—while you sleep—income. I celebrate the audacity and hubris to live by your own exclusive authority and take your own chances. Read More


  1. Wilbur on January 15, 2016 at 11:30

    Maybe the conclusion ought to be that we have 1/10th the gut bacteria that we ought to have? Leach says the Hazda poop 3-5 times per day. My volume is significantly more than before, and 10 times might not be far off. Really, I don’t see why this is important at all.

  2. Tim on January 15, 2016 at 14:11

    And even this new info does not take into account the fungi and other microbes present in a healthy human. Fungi may actually outnumber the bacteria, if not in diversity, in sheer numbers.

  3. Harriet on January 15, 2016 at 16:23

    And how does this impact on the gene count? Along with the 1/10 of the cells in the body being yours was a 1/100 genes in your body come from your parents. I guess that is up for grabs too? Not that it bothers me. I did wonder how they could make the 1/10 statement anyway.

  4. Jimbo on January 18, 2016 at 10:26

    Seems like the default assumption is always that more is better when it comes to gut buddies. I’m not so sure that’s correct. I’ve been wondering why things like coconut oil, apple cider vinegar, and iodine, to name a few, are considered good for you, yet are antimicrobial? Is it that they know to kill the bad guys only? Always seemed contradictory to me.

  5. Jon on January 21, 2016 at 07:59

    Words to live by:

    “In the world were everything is an error on some level, and you attempt to be a little less erring over time, it’s intuitive that it ought to be more prudent to under error than over error.”

  6. poop monster on November 24, 2016 at 11:19

    Is this why you didn’t publish the book?

    • Richard Nikoley on November 24, 2016 at 11:45


      The book will be published, just not in the traditional way.

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