Gut Feelings -- Science, Yogurt, and Stress

Got genuinely excited last week when this month's Scientific American magazine showed up in my mailbox, and the cover was a picture of a human body full of microbes. The cover article is, "Your Inner Ecosystem: In your body bacteria outnumber your own cells 10 to 1. Who's in control?"

 Why the excitement? To the dismay of my kids (ages 10-15) on long car rides and over several dinner talks over the past few months, I've been sharing stories from recently published research about beneficial bacteria inside of us and other creatures. Mostly research on mice and fruit flies, but all with fascinating possible implications on human digestion, obesity, cancers, stress management, mate selection, and overall behavior and evolution.

A sampling below of my recent readings and podcasts on this topic, that brought on these lectures that brought on my interest in learning more about gut bacteria, and talking about :

-- My favorite one: lab mice with rich yogurt diets (live yogurt bacteria) manage stressful situations (being dropped in a bowl of water) much better than mice with normal diets, by continuing to persevere, looking for an answer to their bad situation far longer and with less panic than their yogurt-less peers.  But if the nerve that communicates between stomach and brain is cut, then both groups of mice are equally panicky.  Likely conclusion: helpful bacteria introduced into mice guts from yogurt diets help mice brains by telling the endocrine system to release calming chemicals into the blood stream.  Link her to the RadioLab Podcast.

-- A fruit fly likes to select a mate who has a similar diet, more often than not.  If you dose the fruit flies with antibiotics, fruit flies start mating randomly, no longer expressing a preference for mates with similar diets.  Likely conclusion: Gut bacteria in fruit flies help to process food, and that processing releases pheromones that attract mates.  Different pheromones from different foods.  When the bacteria are killed by antibiotics, that whole process is changed.  Link to a brief article, without the antibiotic stuff – I read that somewhere else.

-- And mice with yogurt diets in a lab have shinier fur, mate more often, and produce more and healthier offspring. 

The Scientific American cover article, written by Jennifer Ackerman, does a great job of introducing the concept of how we’ve evolved to work with the bacteria inside of us on a cellular level.  In many cases, the bacteria perform vital tasks for us, and scientists are just now discovering that even bacteria previously thought to be only harmful (e.g. H Pylori causing ulcers) are actually needed (H. Pylori helps us regulate how much we eat).

Snippet from the article:  “Bacterial cells in the body outnumber human cells by a factor of 10 to 1. Yet only recently have researchers begun to elucidate the beneficial roles these microbes play in fostering health. Some of these bacteria possess genes that encode for beneficial compounds that the body cannot make on its own. Other bacteria seem to train the body not to overreact to outside threats. Advances in computing and gene sequencing are allowing investigators to create a detailed catalogue of all the bacterial genes that make up this so-called microbiome. Unfortunately, the inadvertent destruction of beneficial microbes by the use of antibiotics, among other things, may be leading to an increase in autoimmune disorders and obesity.“  Really worth picking up the magazine or subscribing to the digital edition to read the whole article.

To this reader and student of science and learning, seems clear that we are just starting to understand what we don’t know about how we work with the bacteria we host.  Lots of study and research needed to learn what our decades-long battle against harmful bacteria (from a long list of life-saving antibiotics) has caused to our relationship with beneficial bacteria that we need to regulate our bodies and minds.

Either way, I’m going to finish this bowl of yogurt this morning (containing at least 5 live bacteria cultures, L. Bulgaricus, S. Thermophilus, BB-12, L. Adicophilus, and L. Casei)) and plan to ingest some nearly every day, with fruit and granola.

George Cigale

gcigale@tutor.com