Probiotic supplementation during pregnancy and the first 2 years of life may provide lasting protection against eczema. Digest
Probiotics have been linked to reduced eczema in early childhood, but it is less clear whether they prevent the condition or merely delay when it appears. A study followed children from infancy into early adolescence to help answer this question.
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The randomized trial included 474 infants in New Zealand at increased risk of allergic disease. At 35 weeks of pregnancy, their mothers were randomly assigned to receive Lactobacillus rhamnosus HN001, Bifidobacterium lactis HN019, or a placebo. Mothers took the probiotic or placebo until 6 months after giving birth, or until they stopped breastfeeding if that occurred sooner. Their infants received the same treatment from birth until 2 years of age. This study reports the 11-year follow-up, evaluating eczema and other allergy-related outcomes after earlier results were published when the children were 2, 4, and 6 years old.
- At age 11, children in the HN001 group were less likely to have had eczema in the previous year. Eczema affected 12.4% of the HN001 group, compared with 26.8% of the placebo group, equivalent to an estimated 54% lower relative risk. When the researchers accounted for children who missed the assessment at age 11, the estimated risk reduction decreased from 54% to 36%.
- Combining the repeated assessments through age 11, 42.1% of children in the HN001 group met the study's criteria for eczema at least once, compared with 59.4% of those in the placebo group.
- HN001 was also linked to fewer children showing allergic sensitization on skin prick testing. Overall, 49.5% of children in the HN001 group had at least one positive allergy test during the first 11 years of life, compared with 62.3% in the placebo group. However, when the researchers looked only at the allergy tests performed at age 11, the groups were not clearly different.
- Wheezing was also less common over childhood. It was reported at least once in 64.2% of children in the HN001 group, compared with 76.8% in the placebo group.
- HN019 was not consistently linked to lower eczema or other allergy-related outcomes.
Eczema is thought to develop through a combination of immune responses and a weakened outer layer of the skin, which allows allergens to enter more easily. Because the probiotic was given during pregnancy and the first 2 years of life, it may have influenced how the immune system and skin barrier developed. Earlier analyses from the same trial found higher levels of two immune-signaling molecules in umbilical cord blood and in breast milk after probiotic supplementation, consistent with a potential early immune effect. HN001 was also linked to lower eczema risk in children with certain immune- or skin-related genetic variants, further supporting a possible role for immune and skin-barrier pathways.
Fewer children returned at age 11 than at the earlier study visits, making it harder to estimate the true size of the benefit. Even so, the findings suggest that certain probiotic strains given early in life may help reduce the risk of eczema well beyond the supplementation period. In Aliquot #100, I discuss factors that influence child development before conception, during pregnancy and infancy, and into the toddler and early childhood years.