Feed your microbiome wisely!

When Science Met Nature…

Human Microbiome. Credit: Paul Rogers, NYT

Jessica’s Science Blog- 03.16.18

Feed your microbiome wisely!

This post is for all my non-biologist friends, family, and acquaintances!!

You may think you’re human. You’re a (wo)man and that means you’re made up of 100% human cells, right? No? OK, you’re wise to my tricks.

Lactobacillus bacteria. Important probiotic for humans. Named for their ability to produce lactic acid as they consume sugar. Credit:

You know that microbes occasionally invade your body, infecting you with, say, the cold or flu virus. So, already we have to assume that some proportion of your body is made up of microbes, be they viral particles, bacterial cells, or parasites (ew, right?). If you had to guess, roughly what percentage of your body is composed of microbes? Are we in the ballpark of 10%, 25%, or maybe 50%?

Geez, even I have to admit that I was FLOORED when I came to find that microorganisms account for about 60-90% of our human bodies!! That’s some sci-fi level stuff! My sharp math skills inform me that our very own human cells comprise a pathetic 10-40% of our bodies (although new estimates question the old finding that microbes outnumber human cells by 10:1). SAY WHAT?

What’s really fascinating is that new research indicates that human individuals may differ dramatically in the number, diversity, and communities of bacteria that they host. Some of this variation may be attributed to the environment, some to diet and lifestyle, and some to maternal or genetic factors (e.g. like what kind of community your mother gave you at birth).

Most of our bacteria is found in our gut

It gets even freakier when we consider our total genetic makeup, 99.9% of which can be attributed to our most intimate of pals, the trillions of microbes that inhabit our bodies. You know what, they’re more than pals, they’re our faithful partners. Among their many functions, we’d be unable to digest food and extract its life-sustaining nutrients without the work of our microbial partners. That’s because most of the bacteria in our bodies live in our guts (especially our colons)!

Recent studies on the human microbiome have revealed that a diverse community of gut bacteria is absolutely essential to human health. For example, there is evidence that the types of bacteria present in our microbiome may influence our mood and behavior. Some scientists have argued that anxiety and depression may closely connected to interactions that occur between particular types of gut microbes and the brain?

If this is true, psychiatrists and psychologists should (in theory) have much to learn from nutritionists. In the future, they may find that their patients respond positively to regular ingestion of active cultures of beneficial bacteria. This is an area of important research for our angst-ridden society.

Maps and slide credited to Jasper Lawrence

Cross-cultural studies of human gut microbiota have also suggested that autoimmune disorders, which commonly occur in the western world (such as lupus and Chrohn’s disease) are quite scarce in developing countries. One proposed explanation is that we are too clean in the west and that the human body evolved to be challenged by parasites, and worms in particular. Along these lines, new therapies are being developed where people are being inoculated with worms to treat inflammatory autoimmune conditions.

All the more reason to encourage your children to play in the dirt! They need to get dirty (and play together in the garden, on the farm, or in mud puddles) to pick up beneficial bacteria and develop their immune systems!!

So, you might be asking yourself: what types of foods should I be incorporating into my diet to pick up beneficial bacteria? The answer is foods that have undergone lactic acid fermentation, aka “LACTOFERMENTED” FOODS. I’ve sampled these delightful foods in homemade batches and in store-bought products. They’re quite tasty!! Here’s a list of my favorite ones:

  • Pickled Veggies

    kefir (fermented milk drink)

  • kefir cheese (kefir made into cheese, duh!)
  • yogurt with multiple species of bacteria (like siggi’s),
  • kombucha (fermented black or green tea),
  • sauerkraut or kimchi (fermented cabbage, German or Korean preparations),
  • sour pickles (available at Jewish delis; NOT the ones preserved in vinegar)
  • pickled veggies or eggs (jars for pickling and recipes for lactofermenting can be found here!)

I’m getting HUNGRY!! I try to eat at least one item on this list daily. Since I’ve been doing this, my seasonal allergies (i.e. from tree and grass pollen) and sneezy/eye watering response to cat dander have have become mild-to-non-existent! Coincidence? You be the judge!! They’re also great probiotics to eat when you’re coming off antibiotics to replenish your gut flora and ward off yucky yeast infections!

That is definitely the weirdest way I’ve ever ended a blog post. You’re welcome.


If you liked this post, be sure to check out my previous blog entries on When Science Met Nature….

FEB: Warriors of cold and flu season

JAN: Adult snow days

NOV: Gorillas have sex, too

OCT: Frogs and spiders, oh my! Surprising food web dynamics in neotropical swamps

SEP: The Long Trail

JUN, JUL, AUG: Tales from a far-flung forest: parts 1, 2, and 3,

MAY: We can be heroes! Finding your community on iNaturalist

FROM 2016: The health benefits of yoga: A scientific perspective.

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