Gut Ecology Matters

The literature on the awareness and relevance of microbial populations to individual health status within various local environments of the human body has been  growing in recent years thanks to significant increase of research funding by the US Federal government.  Historically, the gastro-intestinal system has been the most recognized locus of microbial scrutiny.  This article summarizes how two diagnoses, diabetes and obesity can be distinguished by the identity of the composition of the host’s bacterial populations. As the findings of investigations accumulates, a more meaningful picture of the diversity and symbiosis of organisms that comprise healthy human beings is coming into focus.


Obesity, T2D May Alter Gut Bacteria

Published: Jun 24, 2014

CHICAGO — The portfolio of gut bacteria in patients with obesity and type 2 diabetes may look different from that of healthy people, researchers reported here.

In a prospective study comparing bacterial composition, patients with obesity and diabetes had lower proportions of some bacterial types — Firmicutes, Bifidobacteria, and Clostridium Leptum — than healthy controls, Yalcin Basaran, MD, of Gulhane Military Medical Academy in Ankara, Turkey, and colleagues reported at the joint meeting of the Endocrine Society and the International Congress on Endocrinology.

There were no significant differences in another major group of bacteria, known as Bacteroidetes, but Basaran told MedPage Today that he would have expected to see a difference if a larger number of patients were included.

The human gut microbiome consists of some 100 trillion bacteria, or some”100 trillion friends you didn’t know you had,” Basaran joked. Researchers have been looking at whether gut microbiota play a role in the increased prevalence of obesity and type 2 diabetes, although the evidence hasn’t been consistent.

Basaran and his team conducted a prospective study involving 27 morbidly obese patients with a mean body mass index (BMI) of 40 kg/m2, 26 patients with newly diagnosed type 2 diabetes (mean BMI 29 kg/m2), and 28 healthy controls (mean BMI 23 kg/m2). Basaran noted that these numbers were far higher than other trials looking at a similar hypothesis, which adds to the study strength.

They used fecal samples to look for the presence of four major types of fecal microbiota — Bacteroidetes, Firmicutes, Bifidobacteria, and Clostridium Leptum — via quantitative real-time polymerase chain reaction (PCR).

Overall, they saw no differences between the three groups in levels of Bacteroidetes, but Basaran noted a larger sample size would have likely shown a difference.

However, proportions of Bifidobacteria, Firmicutes, and Clostridium Leptum levels were significantly lower among obese and diabetic patients compared with healthy controls:

  • Firmicutes: 4% lower in obese patients, 13% lower in diabetes patients (P<0.001)
  • Bifidobacteria: 14% lower in obese patients, 28% lower in diabetes patients (P<0.001)
  • Clostridium Leptum: 14% lower in obese patients, 11% lower in diabetes patients (P<0.001)

In further analyses, Basaran and colleagues found that metabolic parameters such as weight (P<0.001), BMI (P<0.001), HbA1c (P=0.011), waist circumference (P<0.001), and fasting blood glucose (P=0.005) were significantly associated with reduced levels of these three types of bacteria in the gut.

The findings support other work showing that both obesity and diabetes may be associated with compositional changes in the intestinal microbial community, and they suggest that gut microbiota may be used as a marker to help determine the risk of metabolic disorders.

Basaran said future research may be helpful in developing therapeutic targets to prevent and treat obesity and diabetes, not just with probiotic compounds, but also with fecal transplantation.

Basaran disclosed no relevant relationships with industry.


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