Thursday, August 11, 2016

Summer reading: Burgers and fries have nearly killed our ancestral microbiome.

Your homework for the weekend as I work on a new blog post.

Please read:  How the Western Diet Has Derailed Our Evolution, by By Moises Velasquez-Manoff, Nov 2015.

A few teasers:

Whereas North American microbes orient toward degrading fat, simple sugars, and protein, the microbes of subsistence communities so far studied are geared toward fermenting fiber.

Antibiotics, available after World War II, can work like napalm, indiscriminately flattening our internal ecosystems. Modern sanitary amenities, which began in the late 19th century, may limit sharing of disease- and health-promoting microbes alike. Today’s houses in today’s cities seal us away from many of the soil, plant, and animal microbes that rained down on us during our evolution, possibly limiting an important source of novelty.

The United States Department of Agriculture recommends between 25 and 38 grams of fiber for adults daily; most Americans consume substantially less fiber-rich food, including nuts, whole grains, certain fruits, and vegetables. The guideline stems, in part, from the research of an Irish-born physician named Denis Burkitt. While working in Uganda in the 1960s, Burkitt became convinced that the high-fiber African diet explained the Africans’ relative lack of colon cancer.

 Here, studies of populations living more traditional lifestyles may provide clues. In the past, most people likely imbibed many times more fiber than today. If you eat minimally processed plants, which humans have for millions of years, you can’t avoid fiber. Modern hunter-gatherers and horticulturalists certainly eat loads of it. The Hadza of Tanzania, for instance, consume at least 10 times more than Americans, in tubers, baobab fruit, and wild berries. Agriculturalists, like those Burkina Fasans, also eat more fiber than Western populations, in porridges and breads made from unrefined grains.

Years ago, while still a post-doc, Sonnenburg discovered that something very odd occurs when those MAC-loving microbes go hungry. They start eating mucus. “This is the stage where you say, ‘Oh my God. They’re eating me.’ ” Sonnenburg said. “You can see it.”We need that mucus. It maintains a necessary distance between us and our microbes. And as it erodes with a poor diet, the lining of the gut becomes irritated. Microbial detritus starts leaking through. One of the more striking discoveries in recent years is that you can see this stuff, called endotoxin, increase in the bloodstream immediately after feeding people a sugary, greasy, fast-food meal. The immune system responds as if under threat, leading to the “simmering inflammation” the Sonnenburgs think drives so many Western diseases.

Enough, lest I give it all away...have a read, and let me know what you think.

Hattip to Lauren for the link!

But if you are like Gemma, and hate homework, just watch this instead!



  1. Great read. It touches on so many themes... if you look closely, it makes some very important points about multi-culturalism and globalism.

  2. I hate homeworks. Time for some fun.

    "Ed Yong & Robert Krulwich | I Contain Multitudes"

    1. FYI, the newest edition of the Fresh Air podcast is an interview with Ed Young.

  3. I cannot do my homework! I'm in the middle of a great book, Washington Square, by Henry James. And the NY Times published a book-length feature story in the magazine section on the middle east - post WW1 to now, profiling six people from different countries to tell the history. Too much to read! But this is now calling me too!


  4. Strand? Is that my bookstore?


  5. This is a GREAT read! Anyone late to this post should check it out! Thanks! I was discouraged when I saw that the no-fiber/yes-sugar mice offspring lost bacterial strains for forever. Then I thought, I wondered what would happen if they were fed real environmental, microbially laden food rather than lab food. Because I'd like to know that there's hope for my daughters even though I ate really horribly during my pregnancies. I see the Sonnenburg microbiologist parents must think something similar as they feature a photo of them in the garden and they describe other food tactics they take to optimize.

    And I LOVE the MAC term: microbiota accessible carbohydrate! Such a better idea/term than "fiber."

    And the mucus layer. I just have to think that's the source of my and so many other people's food intolerances, the absence of that layer due to lifelong bad food choices, antibiotics, stress, etc. That leaky gut is contributing to so many people's illnesses of systemic issues, and gluten-intolerance is simply one example, of which there are many.

    And mostly, I love the way the research Sonnenburgs oriented it all toward a positive, optimistic take which says, "Maybe we can't fix it 100%, but we can make it way better!"

    Thanks. I hadn't followed too much about them. But I really enjoyed this read.