Breastfeeding and food avoidance are ineffective in preventing sensitization in high risk children

Data supporting a primary prevention strategy for food allergy are mixed. We undertook a randomized multifaceted primary prevention study in high risk families defined as at least one first degree relative with asthma or two with a history of other IgE mediated allergy. Mothers in the intervention group completely avoided peanut, nuts and fish and decreased intake of milk and eggs during the third trimester and while breastfeeding for up to 1 year. A partially hydrolyzed formula supplement was provided for the first year, if required. Controls followed usual care of their physician. Epicutaneous testing was performed at 1, 2, and 7 years. Sensitization at 1 year to milk, egg and peanut was 16 (4%), 48 (19%) and 23 (9%) for intervention (n=251) and 11 (4%), 36 (14%), 16 (7%) for control (n=246); at 2 years 9 (4%), 28 (12%), 21 (9%) for intervention (n=242) and 2 (1%), 14 (6%), 20 (9%) for control (n=231) and at 7 years 2 (1%), 1 (1%), 21 (11%) for intervention (n=185) and 2 (1%), 6 (4%), 12 (7%) for control (n=169). There was a significant difference only at two years for less egg sensitization in controls (p=0.037) and a trend for less sensitization in controls to milk at 2 years (p=0.06) and to egg (p=0.06) at 7 years. High risk children frequently sensitize to common foods in infancy but sensitization often resolves to milk and egg. Partial food avoidance strategies in the third trimester and during breastfeeding are ineffective in preventing and may enhance sensitization to food in high risk children.