The Protective Effect of Moderate Maternal Peanut Consumption on Peanut Sensitization and Allergy

To evaluate whether maternal peanut consumption during breastfeeding provides a protective effect against the development of peanut sensitization and allergy in infants who did not consume peanuts in their diet.The study population data were obtained from the Learning Early About Peanut Allergy (LEAP) trial in 2015. The LEAP study included infants with severe eczema and/or egg allergy between the ages of 4 and 11 months old. Infants were then randomized into either the peanut avoidance or peanut consumption group; those in the latter group consumed 6 grams of peanut protein every week until they reached 60 months of age. Baseline maternal peanut consumption during pregnancy, breastfeeding, and within the household was reported by the mothers in grams per week.The study analyzed data from the 2015 LEAP randomized controlled trial, which had previously shown lower rates of peanut allergy in high-risk infants (those with severe eczema and/or egg allergy) who had early peanut introduction. Only the group of infants who were randomized to the peanut avoidance group were included in this analysis. The infants had skin prick testing (SPT) for peanut at baseline, then again at 12, 30, and 60 months of age. SPT wheal diameter greater than or equal to 3 mm was defined as a positive for peanut sensitization. At 60 months old, the children completed a 5-gram peanut oral food challenge to evaluate for peanut allergy. To test the association between maternal peanut consumption (subdivided into “no,” “low,” or “high” consumption) and SPT or oral food challenge at 60 months old, χ2 test was used. “High” maternal peanut consumption was defined as consumption of more than 5 grams of peanuts per week.The study included 303 children who were enrolled in the LEAP peanut-avoidance or control group. They were divided into 3 subgroups for analysis: “no,” “low,” and “high” maternal peanut consumption. Among mothers who consumed peanuts while breastfeeding, the median number of peanut protein ingested was 2.55 grams per week. Lactating mothers in the “low” consumption group (n = 69) ingested a median of 1.45 grams per week (interquartile range 0.79–2.60), whereas those in the “high” consumption group (n = 31) ingested a median of 16.10 grams per week (interquartile range 7.50–26.11). Of the 303 participants, 181 mothers did not consume any peanut while breastfeeding. Participant characteristics, such as age, birth history (gestational age, type of birth, birth weight), ethnicity, maternal smoke exposure, household cats or dogs, duration of breastfeeding, and baseline SPT values, did not vary significantly between the 3 subgroups. Maternal eczema history did show a statistically significant difference between the 3 groups; however, 43% of the 303 participants did not provide that history. Peanut sensitization rates were lower in the “low” maternal consumption group at 60 months of age, compared with the “no” and “high” groups (P = .03). Infants in the “low” consumption group did show lower occurrences of peanut allergy compared with all other groups, but this was not statistically significant (P = .07). A logistic regression model showed that ethnicity (P = .046), baseline peanut SPT (P < .001), lack of maternal peanut consumption while breastfeeding (P = .008), and baseline SCORing Atopic Dermatitis score > 40 (P = .007) contributed significantly to peanut sensitization and allergy at 60 months of age. Presence of maternal asthma contributed significantly to the peanut sensitization model (P = .01) but not the allergy model (P = .39). Certain paternal factors contributed significantly to the peanut allergy model, including paternal rhinoconjunctivitis (P = .02) and paternal eczema (P = .04).Moderate (5 grams or less) maternal consumption of peanut while breastfeeding showed a statistically significant protective effect against the development of peanut sensitization. Alternatively, high maternal peanut consumption potentially bypasses the effect of oral exposure and peanut tolerance that is provided by moderate consumption and, instead, increases the risk for peanut allergy and sensitization.Since findings from the 2015 LEAP study were published, early peanut introduction has been more widely supported and encouraged. It has shown to decrease the risk of peanut allergies in children, which is especially important in children with severe eczema and asthma, who are already at high risk for food allergies. This study further expands on findings from the LEAP trial to analyze the effects of maternal peanut consumption while breastfeeding infants who were not introduced to peanut. Although it is limited by the prior study’s existing data and a small sample size, it adds to the current and ongoing literature on the effects of maternal allergen consumption in reducing food allergic outcomes. However, further research is needed to study the effects of allergen transfer through breastmilk and the mechanisms by which it may induce oral tolerance in the infant.