Does breastfeeding protect against risk of allergies for children?
There is some evidence to support exclusive breastfeeding for 3-4 months in decreasing the cumulative incidence of eczema in the first 2 years of life, but no evidence to support longer duration of either exclusive or partial breastfeeding (Greer et al. 2019). The only breastfeeding intervention trial which examined eczema as an outcome found the odds of atopic eczema in infants in the breastfeeding promotion vs control group was reduced by 46% (3.3% vs. 6.3%; aOR 0.54, 95%CI 0.31-0.95) (Kramer et al. 2001). Authors of a systematic review concluded that the evidence on breastfeeding and food allergies, allergic rhinitis, and atopic dermatitis is limited and insufficient to determine a relationship with breastfeeding (Güngör et al. 2019). Authors of a systematic review concluded that the evidence on breastfeeding and food allergies, allergic rhinitis, and atopic dermatitis is insufficient to draw conclusions (de Silva et al. 2020). There is a lack of knowledge about actual breastfeeding practices in included published studies.
However, exposure to food antigens via breastmilk may be a consideration. A Canadian study examined the effect of maternal consumption of peanuts while breastfeeding and/or introduction to the infants’ diet in the first 12 months of life on peanut sensitisation at age 7 years (Pitt et al. 2018). The incidence of peanut sensitisation was lowest in children whose mothers’ consumed peanuts while breastfeeding and introduced peanuts in the infants’ diet before 12 months of age (1.7%), with a significantly higher incidence with either exposure in isolation i.e. either maternal consumption (with delayed peanut introduction beyond 12 months of age, 15.6%) or infant consumption by 12 months of age (but maternal avoidance whilst breastfeeding, 17.6%).
Maternal diet during breastfeeding
The current evidence does not support a protective effect of excluding common allergenic foods from the maternal diet (e.g. cow’s milk, egg, peanut) during pregnancy or lactation for reducing allergic disease development in their infants (Garcia-Larsen et al. 2018, Greer et al. 2019, de Silva et al. 2020). In fact, of note, a systematic review of studies measuring the excretion of food proteins from the maternal diet into breastmilk appear to be at values well below those likely to induce a reaction in infants with a food allergy, with the probability of an IgE-mediated allergic reaction from breastmilk food protein exposure estimated at ≤1:1000 for cow’s milk, egg, wheat and peanut (Gamirova et al. 2022). Unless otherwise indicated for maternal medical reasons (e.g. diagnosed maternal food allergy), women should be encouraged to consume a wide variety of nutritious foods, including common allergenic foods. Women should be encouraged to follow the dietary guidelines to ensure adequate nutrition to support their recovery, health and wellbeing in the postpartum period and while breastfeeding.
Recommended servings per day, from the five groups for women aged 19-50 years. Breastfeeding women are recommended to increase their intake of vegetables and grains. (Aust. Dietary Guidelines).