The Bacterial Microbiome and Non-Native Fiber: A Halloween Tale

Today is Halloween here in the United States, so I figure it’s the perfect day for a super scary post about fiber.


Not kidding.  This has me terrified.

Dr. Liping Zhao is a professor in the Department of Biochemistry and Microbiology at Rutgers University in the USA who conducts research on how food impacts the bacterial microbiome, and how it can be used to improve human health.  For example, his team have discovered how a high fiber diet can benefit those with type 2 diabetes.

An article on Gut Microbiota for Health describes a recent interview with Dr. Zhao, conducted at a huge international summit on the microbiome, down in Miami, Florida.[i]

You know, from reading my blog, that fiber may be the most crucial factor in gut microbiome health.  According to Dr. Zhao, however, fiber is not just fiber.  It is critically important that you consume the fiber that was a part of your traditional diet, with which your ancestors co-evolved for thousands of years.

His reason?  He has found that there is a core group of bacteria that essentially act as a “foundation for better health” in each of us, and that core group requires certain fibers as food to maintain itself (and to protect us against the growth of pathogenic bacteria).

Says Dr. Zhao:  “If you are born in a Mediterranean country, better to keep your Mediterranean diet…Over generations, your family has been eating a traditional local diet, so the bacteria you take from your parents, and particularly from your mother, have been feeding on that same diet. That’s why our bacteria are most likely using the same nutrients.”  He goes on to state that moving to another country, adopting a ‘foreign’ diet with its different kinds and amounts of fiber, can be extremely problematic in that this may change your core bacteria, and leave you open to the growth of pathogenic ones.

And how’s this for creepy?  Even staying at home and regularly eating foods from other parts of the world can cause issues!

Dr. Zhao also points out that it’s not only what you eat, but also, how you cook it.  For example, in the Mediterranean, pasta and risotto are eaten al dente, which leads to their starch content being less digestible by us, humans; thus, their fiber is more available for the gut’s bacteria.

Dr. Zhao’s statements don’t completely surprise me.  Some of you may remember that back in November, 2018, I wrote about what happens to the immigrant microbiome when people  move to the United States[ii]:

 “Researchers looked at people from Southeast Asia and found that there was a significant reduction in the diversity of gut microbes with each subsequent generation, culminating with their microbiota resembling those of Americans of European origin. The dominant species of the recent immigrants was Prevotella but that changed remarkably quickly to Bacteroides. Prevotella is important in the digestion of high fiber foods, which are much more predominant in an Asian diet (as opposed to the “western” diet, which is heavy in sugar, fat and protein). Dan Knights, a co-author of the study, points to the change in diet as a key factor in this loss of diversity which changes within just a few months: “People began to lose their native microbes almost immediately after arriving in the U.S. The loss of diversity was quite pronounced: Just coming to the USA, just living in the USA, was associated with a loss of about 15 percent of microbiome diversity….The change in diet, and the loss of microbial diversity, was clearly associated with an increase in obesity and diabetes.”

And there you have it:  people move to a new country, start to eat the native diet meaning that fiber amounts and types change…and the next thing you know, they are suffering from some inflammatory disease or another.

So…scary, right?!

p.s.  Cue haunted house music:  the camera pans down, in a dark room full of eerie shadows, to find Judy sitting down at the table to scarf down her beloved vegetable korma with a side of naan bread and a mango lassi….

Man eats cauliflower spicy curry with rice and naan bread



[ii] tps://

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