The amount of microbial bacteria a baby is exposed to in the first seven days of life could determine whether they develop childhood eczema, new Australian research suggests.
The study, from the Murdoch Children’s Research Institute in Melbourne, looked at the gut bacteria of 98 babies who were at increased risk of allergic disease because they had a parent or sibling with a diagnosed allergy.
Associate Professor Mimi Tang, the study’s lead author, says infants with less diverse gut bacteria were more likely to have developed eczema.
“The ones who had eczema, way back when they were only seven days old, had fewer bugs and less faeces and uneven expression of the bugs in their gut [than those who didn’t develop eczema],” she said.
“This suggests that altering the mix and amount of bacteria in our guts in early life could be an effective approach to the prevention of eczema, especially for those with an increased risk of developing allergic disease.”
The Murdoch Children’s Research Institute study is the largest to examine the relationship between very early life gut bacteria and the subsequent development of allergic disease.
Researchers measured the infants’ gut bacteria by testing faecal samples at five points over the first 12 months, and they were checked for eczema at three, six and 12 months.
Of the infants 33.7 per cent developed eczema in the first 12 months, while 24.4 per cent had at least one positive allergy test to a food or inhalant – and were therefore considered to be predisposed to develop an allergy.
The research, published in the Pediatric Allergy and Immunology journal, fits in with the so-called “hygiene hypothesis”.
“It is currently the most popular theory for why rates of allergy problems have gone up,” Associate Professor Tang said.
“We know rates of allergic disease are going up and it is related to the Western lifestyle. The most significant difference that we’ve been able to identify is reduced microbial exposures in early life.”
Before birth, a baby’s gut is sterile, but during their first few days of life they are exposed to a range of factors that can affect how these essential gut bacteria develop.
Factors known to influence this process include whether a baby was delivered vaginally or by Caesarean, whether the baby is breastfed or fed on formula, whether the baby or mother was given any antibiotics and the contact with parents, siblings and hospital staff.
Associate Professor Tang says this early exposure to microbial bacteria is very important.
“The most dramatic or significant microbial exposure that any individual has throughout their entire lifetime is the acquisition of their intestinal microbiota,” she said.
“There are 10 times more microbiota in our gut than there are human cells in the body.”