Obesity Link – More Reason for Caution with Antibiotics

November 12, 2012 — According to two new studies , one in mice and one in humans, the use of antibiotics in young children may be linked to obesity later on. The researchers suggest the correlation may be due to the effects antibiotics have on the mix of bacteria in the intestines, altering a complex web of mechanisms that regulate metabolism, appetite, and weight.

The first study, published in Nature, mimicked in mice the low doses of antibiotics farm animals in the US have been receiving for decades, even in the absence of disease, which have increased the size of the animals by about 10%. The mice in the study did not become larger overall, but they became more obese. The researchers then examined the bacteria in the mice’s intestines and discovered that species of bacteria, previously found to be related to obesity in mice, were more evident in the intestines of the mice treated with bacteria.

A second study among 11,000 children in England, published in the International Journal of Obesity, showed that obesity at age three, and to a lesser extent at age seven, correlated well with whether a child received antibiotics in the first six months of life. 

Scientists are quick to say that results preliminary. But when considered along with other data, they strengthen the idea that obesity might depend on the composition of intestinal bacteria. We’ve known for some time that over-use of antibiotics has many bad effects. These studies suggest that obesity risk may be another reason to be cautious.

You can read about the risks of misusing antibiotics, including the link to obesity, in the Pittsburgh Post-Gazette here. Read the study in Nature here and the study in the International Journal of Obesity here.