Me, Microbes, and I


It has been said that “No man is an island.” While you may quibble that it should be “No one is an island,” we know what it means: We human beings depend on one another. We depend on each other, and we also depend on ecosystems to provide us with water and clean air—among other things. Yet there are other important ecosystems within us and on us.

You are no island: no, you are more of a continent complete with colonists, invaders, battles for resources, and turf wars. And there are a lot more of “them” than there are of “you,” about one hundred trillion of them. As one article in the Economist put the idea, “…humans are not single organisms, but superorganisms made up of lots of smaller organisms working together.”

Microbes can be used in soil cleanup

Microbes (Photo credit: Wikipedia)

We have known for a long time that our guts harbor “good” bacteria (yogurt companies advertise about probiotics) and health officials caution against unnecessarily taking antibiotics which could harm good bacteria. These bacteria, it turns out, have evolved along with us (Homo sapiens) and are part of our being. And, in turn, our bacteria evolve within us, having numerous generations during a person’s lifespan, and adapting to changing conditions.

What is now coming out of research is how essential those bacteria are to our physical and mental health. For instance, on our skin, “Staphylococcus epidermidis fends off skin infection and enhances immunity,” the Economist article says. Maybe that antibacterial soap isn’t your best choice for healthy skin.

Researchers call the symbiotic relationship that microbes have with particular animals or plants a microbiome. The sheer magnitude and diversity of your microbiome is staggering. “The typical human is home to a vast array of microbes,” evolutionary biologist Olivia Judson wrote in the New York Times. “If you were to count them, you’d find that microbial cells outnumber your own by a factor of 10. On a cell-by-cell basis, then, you are only 10 percent human. For the rest, you are microbial.” A human being has 23,000 different genes. Our microbiome has almost 150 times that number, about three million genes.

In their proper places, microbiomes are truly symbiotic, a collaboration of human and micro-critter. We provide hospitable living conditions, and the microbes help break down foods for digestion, synthesize vitamins, and help our immune system. Inoculation with microbiota begins when we travel through the birth canal. Among other things, our new gut bacteria will “affect the wiring of nerves in the stress system, influencing how the body reacts to stress for the rest of its life,” writes Tom Siegfried in Science News. Our mothers’ influence, then, goes even further than we knew.

When they are not in their proper place or when unwanted bacteria come in, the results can be distressing, painful, or even deadly for the host. Researchers have linked off-kilter microbiomes to obesity, diabetes, heart disease, autism, and some autoimmune diseases.

Rejiggering some microbiomes apparently cures some diseases. “The past few years have shown that having good relations with the 100 trillion bacteria which inhabit the gut is essential to human health,” reports an Economist article. “If relations break down, hostile bacteria may invade and previously friendly ones may turn hostile. When things do go wrong, though, doses of corrective bacteria can make a difference.”

The method of delivery for healthy bacteria to the intestine is rather yucky. Yes, eating yogurt with probiotics can help people with irritable bowel syndrome, but pretty much everything else requires a fecal transplant—a “trans-poo-sion,” if you will. Gastroenterologist Thomas Borody says, “By implanting another person’s stool, that other person may contain bacteria which manufacture antibiotics. And this is the key: bacteria make molecules that kill other bacteria. In fact, most antibiotics come from bacteria.” Fecal transplants can change the gut’s microbiome, and this changes our health.

Scientists have just begun to understand our microbiome’s interaction with us. For one thing, there is much to learn simply due to the number of these critters. “The adult human intestine contains trillions of bacteria, representing hundreds of species and thousands of subspecies,” one scientific abstract says. We are also at the beginning of this scientific process; a time that is analogous to when people knew willow tree bark relieved headaches but had not yet identified acetylsalicylic acid (the active ingredient in aspirin) as the reason.

Our microbiomes and earth’s biomes (plants and animals found in particular habitats) have evolved and continue to evolve as conditions change. Understanding their complexities will help improve our lives. And, as always, more research is needed.

Updated: Now with 100% more Steve Martin.

You know, medicine is not an exact science, but we are learning all the time. Why, just fifty years ago, they thought a disease like your daughter’s was caused by demonic possession or witchcraft. But nowadays we know that Isabelle is suffering from an imbalance of bodily humors, perhaps caused by a toad or a small dwarf living in her stomach.



References/Further Reading

Dubner, S. (2011, March 4). Freakonomics. Retrieved June 6, 2013, from The Power of Poop:

Flam, F. (2012, June 9). Retrieved June 7, 2013, from We and Our Microbes are in This Together:

Jane A. Foster, K.-A. M. (2013, May). Gut–brain axis: how the microbiome influences anxiety and depression . Retrieved June 4, 2013, from ScienceDirect:

Gavura, Scott. I’ve been prescribed an antibiotic. Should I take a probiotic?

Judson, O. (2009, July 21). Microbes ‘R’ Us. Retrieved June 7, 2013, from New York Times:

Perelman School of Medicine at the University of Pennsylvania. (2012, March 15). Genetic Variation in Human Gut Viruses Could be Raw Material for Inner Evolution, Perelman School of Medicine Study Finds. Retrieved June 13, 2013, from Penn Medicine:

Perry, W. (2012, July 6). Protective Skin Microbes Help Fight Off Disease,. Retrieved June 5, 2013, from LiveScience:

PsMag. Our Destiny Lies Not in Our Stars, But in Our Bacteria.

Siegfried, T. (2013, May 28). Microbes at home in your gut may also be influencing your brain. Retrieved June 4, 2013, from Science News:

The Economist. (2013, February 21). Evolution: History Repeating. Retrieved June 7, 2013, from The Economist:

The Economist. (2013, April 11). Microbes and men: Consumer microbiomics . Retrieved June 6, 2013, from The Economist:

The Economist. (2012, August 18). The human microbiome: Me, myself, us. Retrieved June 4, 2013, from The Economist:

The Economist. (2012, November 3). Treating disease with microbes: Bugs in the system. Retrieved June 4, 2013, from The Economist:

Virginia Tech. (2013, February 8). Villain stomach bug may have a sweet side. Retrieved June 6, 2013, from EurekaAlert!:

Xu J, M. M. (2007, July 5). Evolution of symbiotic bacteria in the distal human intestine. Retrieved June 6, 2013, from

Zimmer, C. (2006, January 3). From Bacteria to Us: What Went Right When Humans Started to Evolve? Retrieved June 4, 2013, from New York Times:

Zimmer, C. (2013, May 22). Meet Your New Symbionts: Trillions of Viruses . Retrieved June 4, 2013, from National Geographic:



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Should there be a new way of living for the top one billion? – iPat edition redux

Steven Earl Salmony of the AWAREness Campaign on The Human Population, commented on Dot Earth’s, “Do the Top Billion Need New Goals?

Dear Timberati,

Do you think there is any chance at all that Paul Ehrlich, despite his poor showing as prognosticator and gambler, will be shown to be one of the greatest scientists of all time?

After all Paul Ehrlich is the forerunner for recent research by Russell Hopfenberg and David Pimentel that appears to indicate with remarkable simplicity that human population dynamics are essentially similar to, not different from, the population dynamics of other species.

Since many too many population experts remain silent about this research and blogmeisters associated with the mass media refuse to discuss the peer-reviewed evidence, perhaps you could take a look at it, make your comments, and encourage by your example others to do the same. You can find the article, Human Population Numbers as a Function of Food Supply, by Hopfenberg and Pimentel on the worldwide web or at the links below.…

Now I visited the site and came away unconvinced and with a feeling that even if it’s well-meaning, it hates humans.

I replied:
Dear Steve,


Paul Ehrlich will be no more right than Tertullian was 1810 years ago, no more right than was Malthus 212 years ago, no more right than was Forrester 38 years ago, no more right than was et. al.

Again, to quote Macauly, “On what principle is it that, when we see nothing but improvement behind us, we are to expect nothing but deterioration before us?”

This ain’t my first rodeo.

I am NOT saying that feeding the 9.2 billion people that will inhabit this earth in 2075 will be a snap. Certainly not, especially if governments and greens try to keep agriculture in the mid 20th century. Yet it can be done as Norman Borlaug wrote a year or two before his death [ed note: here I’m incorrect, the quote is from 2002 and Borlaug died in 2009], “While challenging, the prospects are good that the world’s farmers will be able to provide a better diet at lower prices to more people in the future.” By the way, after the population peak, the UN (and other demographers) projects world population to fall.

Here’s the human race‘s track record so far:

“The availability of almost everything a person could want or need has been going rapidly upwards for 200 years and erratically upwards for 10,000 years before that: years of lifespan, mouthfuls of clean water, lungfuls of clean air, hours of privacy, means of travelling faster than you can run, ways of communicating farther than you can shout. This generation of human beings has access to more calories, watts, lumen-hours, square feet, gigabytes, megahertz, light years, nanometres, bushels per acre, miles per gallon, food miles, air miles and, of course, cash than any that went before.” (The Rational Optimist, Matt Ridley)

This, not despite free trade, but because of free trade.

However, according to the slide show, food production increase = population growth, or put another way, “If you feed them, they will come.” I disagree. While true for most animals, as ecologists are wont to point out the boom/bust nature of animal populations and food supply, it’s not true for humans. The number of children per woman links much better to infant mortality (arguably, if you want to lower birth rate you would feed people better not feed them less). So, the healthier (and more urbanized and wealthier) we become, the fewer babies women produce. (See graphs: and Note Mauritius and Botswana) packages Malthus’s theory as Powerpoint. I fundamentally find the solution morally repugnant. It’s wildly misanthropic in its neo-Malthusian demand that we not increase food production because that will fuel a population explosion.

And, as you well know, population growth is plummeting. Not one country has a higher birth rate now than it had in 1960.

“Most environmentalists still haven’t gotten the word,” writes Stewart Brand (of Whole Earth Catalog fame), “On every part of every continent and in every culture (even Mormon), birth rates are headed down. They reach replacement level and keep dropping.”

Again, I am not saying things will magically become better. I am saying that increasing the wealth of all and placing resources in the places where we (the top one billion) get the best bang for the buck makes sense to me.

What should we top one billion commit to? (List from the Copenhagen Consensus Center)

1 Micronutrient supplements for children (vitamin A and zinc) to combat malnutrition
2 Enact the Doha development agenda to promote free trade
3 Micronutrient fortification (iron and salt iodization) to combat malnutrition
4 Expand immunization coverage for children
5 Biofortification to combat malnutrition
6 Deworming and other nutrition programs at school to combat malnutrition and improve Education
7 Lowering the price of schooling
8 Increase and improve girl’s schooling
9 Community-based nutrition promotion to combat malnutrition
10 Provide support for women’s reproductive role

You and I may not be able to reach an understanding with this one. This may be a case of what Easterbrook terms, “The collective refusal to believe that life is getting better.” For me, not only is the glass half-full, there’s evidence that everyone will have more to drink soon.


I doubt that I can change Dr Salmony’s mind. After all, he believes enough in the inevitability of the population implosion, (where humanity runs out of food and other resources causing a dramatic drop in numbers. Billions will perish) that he heads a campaign and now is in competition to get attention and funds.

I do hope to change the minds of some who visit Andrew Revkin’s Dot Earth blog. Instead of contributing to, what to my mind is a misanthropic endeavor, that they consider one or all of these three charities: FARM-Africa, International Policy Network, AgBioWorld Foundation

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