The mice showed increased anxiety and aggression.
“Antibiotics aren’t only prescribed, but they’re also found in meat and dairy products.”
The researchers investigated 12 pregnant mice until after they gave birth – providing five with just water, four with water laced with the antibiotic penicillin, and three with penicillin-laced water and a probiotic called Lactobacillus rhamnosus.
When the mice gave birth, the researchers ended up with 72 pups and they found that those who were given the antibiotic had long-term changes in both their behaviour and their gut bacteria.
“We find that penicillin has lasting effects in both sexes on gut microbiota, increases cytokine expression in frontal cortex, modifies blood–brain barrier integrity and alters behaviour,” the researchers wrote in the paper.
“The antibiotic-treated mice exhibit impaired anxiety-like and social behaviours, and display aggression.”
But this isn’t the end of the world, because the group given a probiotic as well had most of the effects of the antibiotic reduced.
Bienenstock told Lindermann that their research flags antibiotics “possible long-term negative effects, especially if given in early life, and identify the possibility that an appropriate probiotic taken twice a day may lessen such detrimental effects.”
But we have to be careful here – this result has only been observed in mice studies. We’ll need further proof in humans before we can say for certain that antibiotics are having an impact.
However, there has been lots of research linking antibiotic-use to change in gut bacteria, leading to an increased risk of a number of diseases.
“Epidemiological studies in humans are suggesting that antibiotic use, and especially long-term use, may be associated with a number of gut conditions including celiac disease, inflammatory bowel disease, colorectal cancer and obesity,” Bienenstock added.
Just another reason to only use antibiotics when they’re required. Your gut microbes will thank you for it.
The research has been published in Nature Communications.