December 21, 2015
A Real Gut Check On Diabetes
By Michael D. Shaw
Maybe, you’re familiar with the numbers. A wonderful meme about our human bodies is that “Microbial cells outnumber human cells ten to one.” Thus, we are more bacterial than human. There are countless references to this on the Web. And, if you read it on the Internet, it must be true, right?
Not so fast. Back in February, 2014, NIH researcher Judah L. Rosner traced the origins of the 10:1 ratio, in a letter to Microbe magazine. It seems to derive from a 1972 paper, written by eccentric biochemist Thomas Luckey. Rosner cites more recent figures, and there’s quite a range: 30 to 400 trillion microorganisms in the human gut and an astonishing 5 to 724 trillion total human cells in the body. Suddenly, this comfortable 10:1 ratio could explode to nearly 100:1, or shrink to a paltry 1:1.
But, there’s no getting around it. Those gut “flora,” as we call them—dating back to the time when bacteria were considered to be part of the plant kingdom—are vitally important. Why “gut”? Sometimes, scientists like to get away from fancy words; besides, it’s so much easier than referring to the “lower alimentary canal.” It is also no coincidence that 60-70 percent of our immune system is located in the gut, and is therefore intimately connected with the microbes.
Given the improvements in genetic analysis over the past decade, and this immune system/gut flora relationship, several investigators have examined differences in gut bacteria between healthy individuals, and those with a particular disease. Type 1 diabetes, a classical autoimmune disease, seems like a good place to start…
Research out of Spain—published in February, 2013—showed that gut microbiota in kids with type 1 diabetes differed significantly from that found in healthy children. Certain genera, and their changed ratio between the two cohorts, could be implicated in the glycemic level of the diabetics. In addition, bacteria crucial in the maintenance of gut integrity (those producing lactic acid and butyrate; and species involved in mucin degradation) were present in far lower numbers in the diabetic kids.
As the researchers put it: “These findings could be useful for developing strategies to control the development of type 1 diabetes by modifying the gut microbiota.” Imagine…Controlling diabetes by growing bugs, instead of injecting insulin.
A brand new paper, out of Russia, entitled “Gut microbiota and diet in patients with different glucose tolerance,” suggests that the presence of certain bacteria in the gut is linked to the development of type 2 diabetes. Gut bacteria in 92 patients (20 type 2 diabetics; 24 pre-diabetics; 48 normal) was analyzed. Thankfully, and unlike many studies on diabetes, none of the patients had any chronic diseases. Far too many studies, including some often cited, bring in type 2s with significant co-morbidities.
Among other findings, the researchers—led by Lilit Egshatyan—were able to link the level of glucose intolerance with the presence of three specific genera: Blautia, Serratia, and Akkermansia bacteria. These bugs are all present in healthy people, but in cases of pre-diabetes and diabetes their numbers increase significantly. Moreover, high fiber diets tended to promote growth of bifidobacteria—considered to be one of the most important components of microbiota, and long a staple of probiotics.
Indications for bifidobacteria therapy include atopic eczema; yeast infections; upper respiratory infections; and lactose intolerance.
As press agents for Egshatyan et al. tout the work: “These findings bring scientists and medical professionals one step closer to understanding the complex reciprocal cause-and-effect relationship between the change in the proportion of certain types of bacteria, metabolic disorders, and diet. According to researchers, one of the possible ways that microbes affect diabetes could be by provoking an immune response.”
Pivoting back to that bacteria cell/human cell ratio, UCSF microbiologist Peter Turnbaugh observed that “Determining absolute numbers is a challenge. Simply put, there’s a tremendous diversity and abundance. The most important thing is that much of what makes us human—many of important aspects of health and the predisposition to disease and recovery—depends on metabolic activity of these microbes. I don’t think it’s all about numbers.”