New research has found that if a mother drinks cow’s milk during the period that she is breastfeeding, it raises her infant’s risk of experiencing skin allergies. The study, published in the Journal of the Medical Association of Thailand, followed 62 mothers and their infants from birth through 4 months of age.

Researchers from Bangkok’s Mahidol University assembled the mothers and infants into two groups. Mothers in one group drank cow’s milk during the first four months of breastfeeding; the control group did not. Eight of the children with mothers drinking cow’s milk had skin allergies, versus two of the children in the control group. All of the mothers exclusively breastfed their infants throughout this period.

An earlier study published in the British Medical Journal followed 124 mothers, 97 of which breastfed their babies. Of those that breastfed, 48 drank no milk or other dairy products and 49 drank milk. Infants in the milk-drinking group experienced 21 cases of eczema, while the no-milk group had only 11 cases. Overall, between the breastfed and non-breastfed infants, the breastfed infants had lower incidences of eczema regardless of the mother’s diet.