Maternal Factors That Influence the Presence of Food Allergens in Human Milk—A Systematic Review ^†

Abstract

Food allergens have been detected in human milk with wide frequency and concentration variations between women. As maternal factors such as age, body mass index (BMI), and allergic disease influence human milk composition, we aimed to identify which maternal characteristics have previously been associated with the presence of food allergens in milk. We conducted a systematic review search in MEDLINE, EMBASE, Cochrane Library, CINAHL, and Scopus, with inclusion criteria of common food allergens, human studies published in English with 10 or more participants providing milk samples, trials, observational studies, letters to the editor, and short communications. We obtained 5125 articles and 4127 after duplicates were removed. After the initial screening, 51 articles underwent full-text assessment, with a final 31 articles included in the analysis. A systematic review tool was used to extract all article information. We found that when a standardized amount of food allergen was consumed (16/31 studies), there were large inter-women variations in the frequency and concentrations of food allergens detected in human milk. The most common maternal characteristics that were investigated to determine their potential to influence the presence of food allergens in human milk were maternal allergic disease, usual diet, and weeks of lactation. Two studies found that if a woman’s diet contained a specific food allergen, this influenced the detection of that food allergen in milk, while three studies found no such influence. Maternal allergic disease positively influenced the detection of food allergens in 3 studies, while 10 studies found no significant associations. Although data on other maternal characteristics, such as BMI, ethnicity, smoking, and parity, were recorded in some studies, these were not investigated for their influence on the presence of food allergens in human milk. Hence, although many studies reported maternal characteristics, most did not explore their associations with food allergens detected in milk. Future research investigating maternal characteristics that influence the presence of food allergens in human milk is needed to contribute to targeted food allergy prevention strategies.