Saturday, November 17, 2012


The fact that over 80% of antibiotics produced in the US is consumed by the animal food industry has been explained away by the need for keeping the meat products safe from contamination by pathogenic bacteria like virulent E.coli, Salmonella and Listeria. However it was later realized that the real purpose of using antibiotics in feed for animals was increasing the weight of the animals before slaughtering which in turn increased the profits of the industry very significantly. Though the meat industry does not admit to this fact, independent studies have confirmed that antibiotics do influence the body mass of the animals in a way not properly understood so far. Of course reducing incidence of contamination is a welcome development though the cost at which this is achieved is some what dubious. If mankind is running out of effective and reliable pool of antibiotics that fight many human diseases, the single most responsible factor is this indiscriminate use (or rather the misuse?) of these life saving drugs for purposes other than saving human lives. Large scale resistance by some of the mutated microorganisms to practically every known antibiotic is an area of intense concern at present.

Why should antibiotics contribute to increased body mass, first observed in laboratory animals a few years ago? Are they really obesogens which interfere with the hormone systems like many endocrine disruptors (ED)? Recent studies connecting antibiotic consumption to body weight increase indicate that they do not work within the body system, their influence being restricted inside the gastro-intestinal tract. It is a common knowledge that most antibiotics knock down intestinal microbial colonies irrespective of whether they are friendly or hostile. One of the earliest empirical observations was that those afflicted by typhoid tend to put on weight after going through the Chloramphenicol antibiotic therapy though the exact cause was not well understood. Also known was the need to replenish the gut microbes through administration of lyophilized cultures of Lactobacilli but the Lactobacilli cultures do not restore fully the profile of microorganisms which were original inhabitants in the gut. Probably this knowledge should have made scientists wiser about likely role of those microbes killed by the antibiotics in body weight increase but not replenished by the standard Lacobacilli therapy.

Now comes the confirmation through recent studies that gut microbes do play a role in fat accumulation in the body though the exact mechanism is yet to be elucidated. Even the identification of these species causing the body to accumulate fat has not been made yet. Only this throws more challenges in elucidating this area further through more detailed and wider studies. Some believe that those microorganisms not killed by the antibiotics become super efficient in extracting calories and converting them into fat. In studies using animals it was found that a gain of 2-4% fat was achieved when they were subjected to administration of low doses of antibiotics for a few weeks. Many farmers do use antibiotics in animals to achieve about 15% body weight on an average. Interestingly the make up of bacteria in animals becoming fatter due to antibiotic consumption resembles that which are present in obese animals, probably lending further weight to the argument that gut microbes are involved in obesity epidemic besides the foods which are rich in sugar and fat.

Against such a background will the world turn its back on reckless use of antibiotics for pecuniary benefits? If this does not happen a tragedy of bigger dimension is waiting to happen. Indirect indication that administration of antibiotics to children during early growth phase could be the real cause of obesity has come out from field studies linking obesity to antibiotic consumption during early childhood. It is alarming to know hear the disturbing possibilities that up to the age of 7 years children could be vulnerable to obesity if frequently treated with antibiotics and the risks are more within the first six months of birth. In a country like the UK it was reported that about 30% of children below the age of 6 months received antibiotic treatment a decade ago. Better sense has prevailed since and physicians seem to be more circumspect in prescribing antibiotics to tender children A consoling factor in this depressing scenario is that adults are not as much in danger as the children are, in getting fatter due to antibiotics.

What are the implications of the above studies on mankind? On one hand here is a situation where the present options vis-a-vis antibiotics are getting more and more limited due to wide scale antibiotic resistance being encountered while no new ones are being developed to counteract more and virulent Frankenstein bugs emerging with each passing day. On top of it wide scale misuse of existing antibiotics, besides not serving the purpose of killing disease causing microbes, tends to make people obese! according to one estimate such antibiotic induced obesity may enlarge the over weight population to the extent of 1.5-2% in the coming years.


1 comment:

Suresh Chander said...

This is a good Piece of information but shocking. I have 2 doubts after reading this article
1. how come Food safety authorities like EFSA or FAO has not investigated this complaint?
2. use of antibiotics in animal feeds will be having a usage allowance and these recommendation are determined based on clinical studies or by animal studies, during the study did the lab test animals showed any obese conditions?

Thanks in advance
Suresh Chander
MSc Food Science (2nd year)
University of Helsinki