“…Human milk provides the breast‐fed child not just with nutrients, but with a mucosal immune system. Milk contains a wide array of molecules with antimicrobial activity: antibodies to bacterial, viral and protozoal antigens (Gillin et al ., 1983; Hanson et al ., 1985; Redhead et al ., 1990; Ogra and Rassin, 1995); bactericidal molecules such as lysozyme and lactoferrin (Reiter, 1984; Lönnerdal, 1985); fatty acids that lyse bacteria and viral particles (Kabara et al ., 1972; Sarkar et al ., 1973; Kabara, 1980); and glycoconjugates that inhibit bacterial adherence to epithelial cells (Andersson et al ., 1983; Svanborg et al ., 1991; Kunz and Rudloff, 1993; Newburg, 1999). These components reach mucosal surfaces in the respiratory and gastrointestinal tracts of the breast‐fed child and are thought to interfere with various steps in disease pathogenesis at these sites (Ofek et al ., 1977; Andersson et al ., 1986; Kunz and Rudloff, 1993).…”