Monday, July 27, 2015

The Link between Gut Microbes Antibiotics And Obesity

Today I will tell you a story; the relation between the microbes in your stomach and obesity.
As usual, this story also has a hero, heroin and a villain. Your stomach, microbes in your gut and antibiotics leads the role respectively.  
How come the antibiotic a villain?
The Link Between Antibiotics And Obesity
To know more about it, you have to read this story to the very end.
The story starts long years ago, in the era of Antony van Leeuwenhoek, who commonly known as ‘the father of microbiology’.  He did improvements in microscope and initiated the study of microbes- microbiology.  And Antony van Leeuwenhoek becomes our first microbiologist. On September 17, 1683, describing “very little animalcules, very prettily a-moving,” which he had seen under a microscope in plaque scraped from his teeth. For more than three centuries after van Leeuwenhoek's observation, 2012 The Human Microbiome Project (HMP) established.
We will have a look at how the relation is building up between our lovers; stomach and microbes.

A Flashback: The school days

The extensive studies shows, the number of Bacteria in an average human body is ten times more than human cells. A total of about 1000 more genes present than in the human genome. Because of their small size, however, microorganisms make up only about 1 to 3 percent of our body mass (that's 2 to 6 pounds of bacteria in a 200-pound adult). These microbes are generally not harmful to us; in fact they are essential for maintaining health. They produce some vitamins which we have no genetic code, some microbes digest our food to extract nutrients which we need to survive, teach our immune systems how to recognize dangerous invaders and even produce helpful anti-inflammatory compounds that fight off other disease-causing microbes.

                      Total Microbiota in human  can weigh up to 2 kg
Gut flora or gut microbiota consist of complex community of microorganisms species that lives in digestive tracts of animals. Bacteria make up most of the flora. Somewhere around 300 to 1000 different species liven in the stomach. Research suggests that the relationship between gut flora and humans is not merely commensal (a non-harmful coexistence), but rather a mutualistic relationship.
Though people can survive without gut flora, the microorganisms perform a host of useful functions, such as fermenting unused energy substrates, training the immune system, preventing growth of harmful, pathogenic bacteria,  producing vitamins for the host, such as biotin and vitamin K, and producing hormones to direct the host to store fats. In return, these microorganisms procure within the host a protected, nutrient-rich environment in which they can thrive. However, in certain conditions, some species are thought to be capable of causing disease by producing infection or increasing cancer risk for the host.

The Relation between Gut Microbiota and Obesity

In my previous post Obesity linked to exposure to Artificial light  we discussed how the over exposure to artificial light leads to obesity. Now we will study the role of microbes.
An early hint that gut microbes might play a role in obesity came from studies comparing intestinal bacteria in obese and lean individuals. In studies of twins who were both lean or both obese, researchers found that the gut community in lean people was like a rain forest brimming with many species but that the community in obese people was less diverse—more like a nutrient-overloaded pond where relatively few species dominate. Lean individuals, for example, tended to have a wider variety of Bacteroidetes, a large tribe of microbes that specialize in breaking down bulky plant starches and fibers into shorter molecules that the body can use as a source of energy.
 The composition of gut microbiota is unique to each individual, just like our fingerprints
Differences in the gut Microbiome exist between obese and lean human. Relative composition of Microbiome at the early life predicts the subsequent development of overweight and obesity.  In a comparison, of obese children and normal-weight children, bifidobacterial numbers during infancy were significantly higher in children remaining at a normal weight at age 7 years, whereas significantly greater numbers of Staphylococcus aureus in infancy were detected in children who subsequently became overweight.

The entry of Antihero: Use of Antibiotics

Now the point is clear that the diversity of the gut Microbiome is very important for a healthy body. From here we will try to identify the relation between obesity and the use of antibiotics.

The rate of Antibiotic Usage in US a state wise comparison : Source CDC

State wise Obesity rate in US . Source:Behavioral Risk Factor Surveillance System :CDC

 Different antimicrobial agents can influence the normal gut microbiota in different ways. The extent of the antibiotic induced alterations in the microbiota depends on several factors: i) the spectrum of the agent, ii) dosage and duration of treatment, iii) route of administration and iv) the pharmacokinetic and pharmaco dynamic properties of the agent. For example, secretion of an antibiotic by intestinal mucosa, bile or salivary glands may subsequently interfere with the normal microbiota at different sites. Other side effects of some antibiotics on the human host include disturbance of the metabolism and absorption of vitamins, alteration of susceptibility to infections and overgrowth of yeast and/or Clostridium.

Research reports on effect of different Antibiotics on Gut Microbiota :Hitectac

Several antibiotics are specifically active against anaerobic bacteria that dominate in the human intestinal microbiota. They play an important role in maintaining a healthy gut, such as producing extensive amounts of volatile fatty acids. Therefore, treatment with antibiotics that select against important groups of anaerobic bacteria can have substantial consequences for the resultant functional stability of the microbiota. One example is clindamycin, a relatively broad-spectrum antibiotic that primarily targets anaerobic bacteria.
 More than 1,000 different known bacterial species can be found in human gut microbiota, but only 150 to 170 predominate in any given subject
Clindamycin has been shown to have a large negative impact on the intestinal microbiota as seen by reduced resistance to colonization by pathogens, leading to a high risk for pseudomembranous colitis due to C. difficile overgrowth. C. difficile is commonly isolated in low numbers from healthy individuals, but may increase in number as a consequence of antibiotic-induced disturbances, in particular following suppression of the normal beneficial members of the anaerobic microbiota. Gastritis and diarrhoea are other recorded clindamycin-induced effects on the intestinal flora and disturbances of normal bowel function can lead to symptoms such as bloating and intestinal pain

Antibiotics linked to childhood obesity

Young children who are given repeated courses of antibiotics are at greater risk than those who use fewer drugs of becoming obese, US researchers say.
There is a correlation observed that , the children had four or more course of antibiotics by the age of 2 were at 10% more high risk of being obese. Even though the direct correlation of antibiotics and obesity is not completely understood, but indirectly it is true. The studies already proved that the high use of antibiotics will alter the gut biome.
US researchers from the University of Pennsylvania and Bloomberg School of Public Health reviewed the health records of more than 64,500 American children between 2001 and 2013.
The children were followed up until they reached five years of age.
Almost 70% of them had been prescribed two courses of antibiotics by the time they were 24 months old.
Do You Know : Drinking Cold Water Will Helps to reduce Obesity'
But those who had four or more courses in this time were at a 10% higher risk of being obese at the age of five than children who had been given fewer drugs.
And the type of antibiotics they were prescribed appeared to make a difference too - those given drugs targeted at a particular bug were less likely to put on weight.
But those given a broad-spectrum antibiotic - that can kill several types of bacteria indiscriminately - were more likely to have a higher body mass.
Prof Charles Bailey at the University of Pennsylvania, said: "We think after antibiotics some of the normal bacteria in our gut that are more efficient at nudging our weight in the right direction may be killed off and bacteria that nudge the metabolism in the wrong direction may be more active."

A couple of years ago I read a research paper on the topic “ Impact of the Gut Microbiota on the Development ofObesity: Current Concepts”  published in Nature. This will be a good read to have some scientific information.


Now we are at the end of our story. Yes this is just a story, just to initiate a thought on your mind. I was trying to spark the link between overuse of antibiotics- directly and through livestock’s- is dangerously changing our gut microbiota. And this microbiota is very essential for our body balance in many ways. 
Generic or broad-spectrum antibiotics are not our friend. Antibiotic usage at infant stage will increase the risk of obesity at later sate. As everyone says “What you are is what you eat”.
The story ends here with a question to you.

Do you know what are prebiotics and probiotics?How prebiotics and Probiotics help you to maintain good health?

Share your answer with us so our microbiota thrives in our gut and make us healthy.
Have a good day… don’t forget to press share buttons below J

About the Author

Prejeesh Sreedharan

Author & Editor

I am a Biotechnologist very much interested in #SciTech (Science And Technology). I closely follow the developments in medical science and life science. I am also very enthusiast in the world of electronics, information technology and robotics. I always looks for ways to make complicated things simpler. And I always believes simplest thing is the most complicated ones.


  1. From the map, we can see that antibiotic has been used widely. But many people do notice its goodness, but they ignore its harm. it also can cause allergen for people.

  2. The activities of gut microbios not only connected with obesity, but also connected with other diseases like cancer, which has already led a new direction ofdrug discovery.

  3. Get help for your tutorials


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