In a study recently published in Nature (August 2012), researchers examined this question using a mouse model of obesity. In the past, many human studies have noted that changes in our gut flora (good versus other intestinal bacteria) can lead to obesity. In those studies, the researchers had used fecal transplants to help people lose weight. That’s right, they removed stool from thin people and placed that stool in the rectal vaults of obese people. The transplanted stool helped the obese person’s gut to establish a different balance of gut bacteria and the obese person lost weight.
In this study, the researchers exposed the mice to very low levels of antibiotics – the levels that would be experienced as a mid-range level for sub therapeutic agricultural usage as approved by the FDA. This means that the levels the mice experienced were not designed to be as strong as a treatment regimen that humans would experience if they were being treated for an infection. However, the levels were also stronger than the trace levels of antibiotics that occur in drinking water across the country as a result of agricultural usage.
They found that YES, the antibiotics caused the intestinal bacteria to change. There weren’t more bacteria. They were just different species. The species of the bacteria shifted toward the type associated with obesity. In addition the mice gained fat mass and created more triglycerides and related fat compounds. The dysfunction that began as a shift in gut bacteria resulted in a change in the digestion and absorption of fats, increased the amount of carbohydrates that were turned into fat, and cause the liver to store that fat more effectively.
This is a huge wake up call – EARLY LIFE ANTIBIOTIC USE CAN INCREASE THE CHANCE THAT YOU OR YOUR CHILDREN CAN GAIN FAT MASS.
Bottomline – avoid antibiotics wherever possible; have your gut flora checked; balance your intestinal bacteria; advocate for the strict regulation of antibiotics in agriculture.