While it is unclear why breastfeeding is protective against SIDS it is clear that breastfed infants are healthier than their bottle-fed counterparts. Possibilities are the protective effect of IgA on bacterial toxins, the presence of long chain polyunsaturated fatty acids, faster development of the central nervous system, and the benefit of tactile stimulation during night feeds.
Kum-Nji, P.et al. Reducing the incidence of Sudden Infant Death Syndrome in the delta region of Mississippi: A three-pronged approach. South Med J 2001-7; 94 (&); 704-10.