Antibiotic use has been rising over the past 70 years, and so is the increase in Obesity. Antibiotics are often prescribed for conditions where no bacterial infection has been confirmed, and the fear is that over–prescribing antibiotics is playing havoc with the good bacteria that live in our intestines.
Variations in the bacterial colonies lining our intestines have already been linked to Irritable Bowel Syndrome, Crohn’s Disease, Asthma, Parkinson’s Disease and Autism.
This research was carried out by Martin Blaser at New York University. Blasers team fed infant mice low doses of penicillin, mimicking doses given to farm animals. After 30 weeks, penicillin fed mice were between 10% and 15% bigger and twice as fat as the drug-free mice. The researchers examined the mices gut flora and found the antibiotic fed mice had a different compliment of gut flora.
In the second experiment germ free mice, which are bred in a sterile environment, and have no gut bacteria were used. Within 5 weeks of being given gut bacteria from the antibiotics fed mice, these mice were 35% larger than the mice with normal gut flora.
Interestingly, the research showed that mice given antibiotics for 4 weeks early on in life were as large mice given antibiotics for 30 weeks. This suggests gut flora may be most vulnerable to disruption in the earliest stages of life.
Although no one yet knows why certain groups of bacteria can affect body weight, we might expect young children exposed antibiotics to gain weight like the mice.
A study carried out at Copenhagen University followed the development of 28,000 babies, they found those given antibiotics within the first 6 months of life were likely to be overweight by 7 years of age, even when their mothers had a healthy weight.
Antibiotics used to treat children may also have a detrimental effect on their Immune System. In a separate study in mice, the researchers found that antibiotics had a detrimental effect on helper T–Cells, a group of immune cells that secrete chemicals to direct immune response.
A recent study, also carried out at New York University, of 3000-year-old Human faeces suggests that the make up of our gut flora has changed markedly. It has been suggested that we may repopulate our gut with the correct balance of healthy, symbiotic gut bacteria. This may help with numerous diseases, but further research is needed.