Meet Your Microbes

You.  Yeah YOU.  Guess what?  You are positively crawling with microbes.  Bacteria, viruses, fungi, and protozoa.   An average-sized human is host to approximately 38 trillion microbes, which is slightly more than the number of actual cells in the human body.  The vast majority of them, up to 90%, reside in your gut.  Microbes are on every patch of your skin.  They’re on your eyeballs. In your ears.  In your lungs.  Wait!   Before you reach for the soap, consider what science has to say about your own personal microbiome.  The field of Microbiome Science is a new one, just 15 years old, but its findings reveal that the bugs you are carrying around are not usually pests or invaders.  They are symbiotes living in harmony with you, and they just might play a bigger role than you think in making you who you are.

Oral bacteria. Colored scanning electron micrograph (SEM) of mixed oral bacteria. The mouth contains a large number of bacteria, most of which are harmless or even beneficial. However, some bacteria can cause throat infections or cause the formation of plaque deposits on the teeth, which may lead to decay. Magnification: x10000 at 10cm wide.

In (and on) your body there is an entire ecosystem that you will never see.  According to scientist Richard Losick, there are thousands of different species of bacteria in the human body.  It appears that our own microbiomes are completely unique, too – it’s possible for two people to have absolutely no overlap in the microbes that inhabit their body.  There is evidence that our personal microbiomes have a surprising level of influence over us – from how much we eat, to how well we perform athletically, to perhaps even influencing our moods.  The new field of Microbiome Science has only begun and so far studies are small, usually involving studying stool samples from humans and then transplanting them into mice to study the effects.  If the idea of a fecal transplant turns your stomach, it might help to know that ingesting another person’s gut microbiome has been a proven therapy in humans to cure a severe antibiotic-resistant intestinal infection known as Clostridium Dificile.

Getting to know the world of microbes has occupied scientists ever since microbes were discovered, and there’s so much more to discover. This is a 19th century artist’s vision of “France in the Year 2000.” Jean Marc Cote(?), Public domain, via Wikimedia Commons

How much influence do microbes really have over us?  And how do they do it? Gut microbiota have been the best studied so far.  It appears that different kinds of intestinal flora can release different kinds of chemical signals that, via nerve cells, immune cells, or the bloodstream, can signal directly to the brain.  For example, we get our sensation of fullness after a meal from our hypothalamus region in the brain.  The hypothalamus gets its signal from chemicals released by enteroendocrine cells in the intestinal wall.  But the enteroendocrine cells themselves are triggered by chemical signals from gut bacteria.  If there is an overgrowth of dangerous bacteria in the gut, other bacteria can send chemical signals to the dendritic cells of the immune system, beginning an immune response.  Some evidence even indicates that certain gut microbes can trigger enterochromaffin cells, the cells that contain the “happy chemical” serotonin.

Although pretty, these Streptococcus Pyogenes bacteria would probably elicit an immune-signaling response from your microbiome.

Can the tiny hitchhikers in your gut really influence mood and overall quality of life?  At the University of Turku in Finland, Dr. Anna Katariina Aatsinki and her colleagues took stool samples from 301 babies.  Babies with the highest proportion of Bifidobacterium were also most likely to exhibit a trait the researchers called “positive emotionality,” a.k.a, happy babies.  In one of the more extensive studies, researchers at Harvard took samples from marathon runners before and after they ran Boston Marathon, and compared them with samples from non-runners.  The marathon runners had a much higher proportion of a bacteria called Veilonella Atypica, which was quite an interesting discovery for the researchers.  Veilonella is a microbe that metabolizes lactate, the same kind of lactate that is produced by muscles as a byproduct of a vigorous workout.  In turn, Veilonella releases propionate, which helps with oxygen metabolism and heart rate.  When mice received a transplant of the runners’ stool, and were given tiny treadmills to run on, the mice who received it ran 13% percent longer than the control group! 

These Eubacteria from yogurt are the friends you want in your microbiome!

Microbiome science is a growing field with tantalizing promise. Could the detectives of the future take “microbiome prints” to identify a suspect?  Could there be a future in which a dose of the right probiotics change a person’s life?  Science is indicating that even though our microbes are tiny, our microbiome is MIGHTY!

A true story of a fecal transplant, discussed by a doctor and patient at the Mayo Clinic:

Dr. Richard Losick on Human Microbiome Research:

The Microbe Menagerie (Paywall):

Drinking the Beer of Eternity: Scientific Research Indicates that Beer was the Inspiration for the Earliest Human Civilization

Beer of Eternity.  Dark Beer. Friend’s Beer. Sweet Beer. Beer of the Protector.  Although these might sound like what you see on the menu of a local craft brewery, they are actually names the Ancient Egyptians gave to their beloved beers thousands of years ago.  In honor of Beer Lover’s Day, Sept. 7, let’s explore the scientific research that indicates fascinating links between not just beer and civilization, but between fermentation and human evolution itself! 

The traditional story of early human history (in a nutshell): about 5 million years ago, early human ancestors came down from the trees to hunt and gather new sources of food.  Then, about 5,000 years ago Hunting and Gathering humans needed more food. Hunting and Gathering Humans domesticated grain and invented agriculture.  Humans settled down to farm and BOOM! Civilization! Then came Beer. 

The beverage was likely discovered when someone tried to cook sprouting grain, not knowing it contained enzymes that liquify the starches in grain into sugars.  Add a little yeast from the air into the concoction, and yeast began to do what it does best: consume sugar and release ethanol alcohol as a byproduct.  No matter how it was discovered, beer was – and remains – a huge hit.  The oldest written recipe on earth is a Sumerian clay tablet praising the Goddess of Beer, Ninkasi, and describing how to make beer.

This 5,000 year old cuneiform from Iran is not the Hymn to Ninkasi but it IS about beer. It records who got payouts of beer and how much. No information about who’s getting the next round could be found.
Jim Kuhn
CC BY 2.0, via Wikimedia Commons

However, between the fields of Archaeology, Anthropology, Chemistry, Genetics, and Brewing Science, there is mounting evidence that indicates the human fixation on fermentation predates settled agricultural civilization by thousands, maybe even MILLIONS of years.  The chemical reaction by which yeast creates alcohol from sugar happens naturally in overripe fruit that falls from trees to the forest floor.  Steven Benner, a biologist at the Foundation for Applied Molecular Evolution in Alachua, Florida, helped discover a genetic mutation that occurred about 10 million years ago in the last shared ancestor between humans and apes.  This mutation produced an enzyme that allowed our distant forbears to digest alcohol 40 times faster than any other animal.  It is the reason that only humans and great apes experience such a multitude of pleasant psychoactive effects from alcohol. 

Pankaj Boruah
CC BY-SA 4.0, via Wikimedia Commons

Benner and his team elucidated “The Drunken Monkey Hypothesis,” proposing that what actually nudged our ancient ancestors out of the trees and onto the forest floor was the search for delicious, nutrient rich, and pleasingly fermented fruit!  In Benner’s words, “You could say we came out of the trees to get a beer.”

Another challenge to traditional notions of early human history is the fact that archaeological and chemical evidence indicates humans may have been brewing up the good stuff long before Urban Civilization as we know it was a twinkle in anyone’s eye. An 11,000 year old site in Turkey called Gobekli Tepe is right in the area in which the first urban civilizations emerged thousands of years later.  The site is marked by several spectacular 16-ton pillars of mysterious origin, but it also contains many huge vats that contain a residue of calcium oxalate, which is released when beer is made.  Near the vats is also a hilltop covered with the bones of prime cuts of gazelle meat.  It’s unknown how the Hunting and Gathering people of the time were able to shape and lift the pillars, but German Archaeological Institute researcher Jens Notroff thinks the secret to gathering so many people for one muscular purpose was the beer. “If you need someone to help you move, you buy them pizza and a couple of beers.”

Gobekli Tepe, the oldest monumental architecture ON EARTH, and probably the site of some really fun parties too.
CC BY-SA 4.0, via Wikimedia Commons

Bringing people together for beer and barbeque was – and remains – a huge hit.  Although it’s still not conclusive, evidence is gathering that it was beer, not bread that inspired our ancient ancestors to domesticate grains.  Harvesting wild plants simply couldn’t provide enough grain.  So our ancestors planted wild grains and over time bred them into higher yielding barley and wheat. This may explain why the earliest known domesticated grain, called einkorn, comes from a site only a few dozen miles from Gobekli Tepe.  Although the theory is not conclusively proven, there is a strong argument that humans did not settle down in large urban communities to farm for food.  They settled down to farm grain for BEER! 

The Oxford Companion to Beer: Definition of The History of  Beer:

An Anthropologist Ponders the Question of the Origins of Civilization while Brewing an Ancient Sumerian Recipe:

The Drunken Monkey Hypothesis and Gobekli Tepe  (Paywall):