Australian researchers say they've found a possible cause for nut allergies, and it's likely to get lactation experts a bit riled up. Investigators at the Australian National University claim that children who are exclusively breastfed for their first six months have a greater risk for developing a nut allergy than those given other foods or fluids, either exclusively or in combination with breast milk. "These results contribute to the argument that breastfeeding by itself does not appear to be protective against nut allergy in children, and that it may in fact be causative of allergy," they wrote in the International Journal of Pediatrics. To explore the possible connection, the researchers analyzed more than 15,000 questionnaires answered by parents of kids entering kindergarten across Australia. The parents replied to questions about whether their kids were allergic to peanuts or other nuts. Respondents also indicated what they fed them in their first six months. Overall, the researchers found the likelihood for developing a nut allergy was one and a half times higher in breast-fed children than in those not breastfed. According to the researchers, this replicated their previous findings, which also drew a link between breastfeeding and subsequent nut allergies. But outside experts say that the connection is far from clear. "I am not aware of studies saying that breastfeeding per se causes a nut allergy," said Dr. Scott Sicherer, a professor of pediatrics at the Jaffe Food Allergy Institute at the Mount Sinai School of Medicine in New York.