RUMA comments on alleged link between the use of antibiotics in food producing animals and obesity in humans
RUMA sets out reasons for its conclusion that the suggestion, reported in UK press, that long term exposure to residues of antibiotics resulting from their administration to animals is leading to obesity in humans is not based on the results of the studies in mice, is not substantiated by any other data, ignores the quality and safety mechanisms built into our food chain and could cause unnecessary consumer concerns (September 2012)
RUMA comments on story about the use of antibiotics in food producing animals and the alleged link to the obesity epidemic that is occurring in Western Europe and other parts of the World.
RUMA notes that a recent study in mice, attempting to assess the potential mechanisms by which antimicrobial growth promoters work in animals, found that low level exposure to antibiotics of very young mice altered the microflora in the gut and also affected the metabolism of these animals resulting in treated mice having more fat tissue than untreated mice. Other studies on humans in this area have led to the suggestion of a possible link between antibiotic treatment in children at a very young age and their ability to gain weight and potentially become obese at a later stage in life. RUMA acknowledges this is an important area of research.
However, RUMA is disappointed by an additional suggestion reported in the UK press, which is not supported by the research. The article(s) in question imply that antibiotic use in animals may have affected the bacterial balance in the human gut and the way food is digested by humans and that this could be a reason for the increase in human obesity. The implication is that long term exposure to residues of antimicrobials resulting from sub-therapeutic administration of these compounds to animals is going to impact on gut micro-flora of children thus leading to obesity.
The sub-therapeutic administration of antibiotics for growth promotion was banned in the EU on 1 January 2006. As the original US study says, such use is still permitted in the USA. However, any antimicrobial product for use in animals in the EU and USA has to meet Maximum Residue Limit (MRL) requirements in order to gain marketing approval. To set the MRLs, independent scientific experts determine an Acceptable Daily Intake (ADI) which is based on a No Observable Effect Level (NOEL). In the case of antimicrobials this has to be a microbiological ADI based on extensive studies to demonstrate unequivocally that there are no effects on gut flora extrapolated to the human situation to simulate life-long exposure. The adherence to withdrawal periods after the use of antibiotics together with rigorous residue surveillance programmes that are carried out by government bodies ensure that the risk of food that might contain potentially harmful residues entering the food chain is exceptionally low – 11 (0.2%) of the 5,122 samples tested in the UK for antimicrobial residues in 2010 were above the MRL.
RUMA is disappointed by the reporting of a factually inaccurate statement attributed to Prof Brendan Wren, Professor of Microbial Pathogenesis, London School of Hygiene & Tropical Medicine that antibiotics are used indiscriminately in livestock and often used to fatten animals. The use of antibiotic growth promoters has been illegal in the EU since 2006 and so they have not been used for several years. Antibiotic use in livestock is permitted only for treatment and control of disease under a veterinary surgeon’s prescription and not for growth promotion. This makes it highly unlikely that farmers will be able to use antibiotics indiscriminately.
In conclusion, the suggestion that long term exposure to residues of antibiotics resulting from administration of these compounds to animals is leading to obesity in humans is not based on the results of the studies in mice, is not substantiated by any other data, ignores the quality and safety mechanisms built into our food chain and could cause unnecessary consumer concerns.