Certain gut bacteria in infants may reduce the risk of developing allergies later in childhood. That’s the finding of new research from the ALADDIN study at Karolinska Institutet, published in Nature Microbiology.
During the first months, a child’s gut flora develops rapidly. The study followed children from birth to age five to see how early bacteria linked to allergy antibodies (IgE) in the blood.
The researchers analyzed series of stool samples from children and their mothers using advanced DNA technology and simultaneously measured various lactic acids produced by the bacteria.
The results were clear: children who had high levels of bifidobacteria that produce aromatic lactic acids at a young age developed fewer allergy antibodies. One of the most important was the lactate 4-hydroxyphenyl lactic acid (4-OH-PLA). These children also had a lower risk of atopic eczema at age two.
Of the factors favoring “good” bacteria, three proved particularly important: vaginal delivery, exclusive breastfeeding during the first two months, contact with older siblings early in life. These conditions seem to help the protective bifidobacteria to establish themselves.
The study shows that the presence of the right gut flora early in life can reduce the risk of allergies. If we can find ways to support these bacteria in infants, perhaps through diet, breastfeeding or other methods, this could ultimately become a new tool for allergy prevention.”
Johan Alm, pediatrician and researcher at the Department of Clinical Research and Education, Södersjukhuset, Karolinska Institutet
In laboratory experiments, the researchers were able to show that 4-OH-PLA lactic acid reduced the production of IgE in immune cells by about 60%. This suggests that the bacteria are not only “present” but are actively influencing the immune system.
The study is a collaboration between Karolinska Institutet, Technical University of Denmark and several international research groups. The study was funded by the Swedish Research Council, the Stockholm Region and several foundations, among others.
