New research from the ALADDIN study at Karolinska Institutet indicates that certain gut bacteria in infants may help reduce the risk of developing allergies during childhood. The findings, published in Nature Microbiology, are based on a study that tracked children from birth to five years old, examining how early bacterial colonization is related to the presence of allergy antibodies (IgE) in their blood.
Researchers collected and analyzed fecal samples from both children and their mothers using advanced DNA techniques. They also measured various lactic acids produced by these bacteria. According to the study, children with higher levels of bifidobacteria that produce aromatic lactic acids early in life developed fewer allergy antibodies. One specific compound, 4-hydroxyphenyl lactate (4-OH-PLA), was highlighted as particularly significant. These children were also found to have a lower risk of developing atopic eczema by age two.
The study identified three key factors that promote the growth of these beneficial bacteria: being born via vaginal delivery, exclusive breastfeeding for the first two months, and early contact with older siblings. These conditions appear to support the establishment of protective bifidobacteria in infants' digestive systems.
Laboratory experiments showed that 4-OH-PLA could reduce IgE production in immune cells by about 60 percent. This finding suggests that these bacteria do more than simply exist in the gut; they may actively influence immune function.
The research was conducted through collaboration between Karolinska Institutet, Technical University of Denmark, and other international partners. Funding came from sources including the Swedish Research Council and Region Stockholm.
