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Bacteria all around us

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Photo: NAID via Wikimedia Commons

Last week we sat in on a discussion hosted by CUESA and Kitchen Table Talks (a joint project of 18 Reasons and Civil Eats) about the unseen and largely unknown world of bacteria, a subject near and dear to FARMcurious.

Moderator Dr. Daphne Miller, family physician and author of Farmacology andThe Jungle Effect, kicked off the conversation by noting that it was only about 150 years ago that scientists first described these microorganisms and at that time the focus was on germs and eradication. It wasn’t until 2007 and the launch of the Human Microbiome Project that we really began to understand the extent of microbial communities. Only 7 years of research so far, wow!

This panel looked not only at the human microbiome, but life in the soil that we grow our food in and, of course, the action of bacteria on fermented foods. There were some interesting parallels.

Dr. Kate Scow, professor of soil science at UC Davis, soil microbial ecologist, and director of the Russell Ranch Sustainable Agriculture Facility, explained that microbes break down matter and liberate nutrients in healthy soil. In order to do this they need carbon (plant matter) to feed on, which is added in manure and compost in organic farming but is not part of chemical fertilizers. As a result, conventional farms have reduced microbial communities, both in quantity and diversity.

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Photo: Christian Guthier via Flickr cc

Kathryn Lukas, local kraut maven and founder of Farmhouse Culture had a similar story to tell. She says that industrial kimchi and kraut makers have tried to culture bacteria to produce more controlled and consistent results with their ferments but found that the naturally occurring bacteria communities on vegetables created the best flavor, possibly because of diversity that can’t be reproduced in the lab. They work with a microbiologist to learn more about the ways a balanced system of microbes transform produce, freeing up vitamins like B12, making easier to digest food and creating flavors that appeal to humans.

Kristen Earle, a researcher and graduate student at Stanford’s Sonnenburg Microbiology Lab, weighed in with evidence that fiber (plants again!) is vital to healthy digestion.  Bacteria do their work as we learned with soil and food, further disassembling, releasing nutrients and making it easier for us to digest and absorb what we eat. With reduced fiber it takes just 10 days before a significant loss of diversity can be measured in the gut and, alarmingly, the remaining bacteria will start feeding on the host (that’s you!). Reintroduction of fiber has been shown to increase diversity, but some species will never be recovered once lost. Fermented foods have been shown to introduce diverse microbes that colonize the gut while probiotic supplements add specific species that work as they pass through but tend not to stick around.

photo by Katie Stoyka for FARMcurious

Photo: Katie Stoyka

All three panelists noted the importance of balanced systems. “Bad” microbes are out there and when we make changes in how we handle the soil, food preparation or our diet the balance can shift, creating unwanted (and unpleasant) results.

How do we keep it balanced? Well, more research is required. There are still a lot of mysteries waiting to be solved! The exciting second stage of the Human Microbiome Project is now underway and looking at the role of the human microbiome in health and disease. The study ends in 2015 and while I wait for  the results I’ll be feeding the microbiome in my garden with compost and the one in my gut with fermented foods and fiber!

(this post originally appeared on the FARMcurious blog 24 Nov 2014)

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