Probiotics may influence immune fun

Probiotics may influence immune function through their effects on local immunity and stabilization of
intestinal barrier integrity. Probiotics are generally regarded as safe for administration to otherwise
normal infants, children, and even pregnant women, and they are available in many food products, such as
live culture yogurt. Human breast milk also may naturally contain probiotics from maternal sources.
Probiotics may be given separately like a medicine or supplement, mixed with or added to a naturally
existing food, or even added to infant formula or human breast milk. 28 However, probiotics may stimulate
growth of gut bacteria and cause deleterious metabolic activity, excessive immune stimulation, and even
systemic infections. Therefore, preterm neonates, children with short bowel syndrome,
immunocompromised patients, and other special hosts, should receive probiotics only after careful
consideration and observation and careful weighing of potential benefits and risks. 38
Prebiotics are nondigestible food ingredients added as supplements to food or infant formulas. Human
breast milk contains many natural prebiotics. 12 Prebiotics used as supplements usually are oligosaccharides
and include fructo-oligosaccharides (FOS), inulin (a group of FOS), galacto-oligosaccharides (GOS), soybean
oligosaccharides, lactulose, and dietary fibers. They are a major substrate for bacteria and are designed to
promote and stimulate the growth of beneficial, indigenous strains of bacteria, especially Bifidobacterium
spp. The effects of prebiotics are potentially broader than a single probiotic strain of bacteria. The
fermentation by-products of prebiotics also produce short-chain fatty acids that may have an antiinflammatory
effect and may directly affect the mucosal and systemic immune systems. A theoretical
concern is that prebiotics may promote growth of potential pathogens or encourage growth of commensal
bacteria that may translocate across the gut epithelial barrier in the preterm neonate with immature gut or
in an immunocompromised host with altered immunity. In the otherwise normal older infant and child,
prebiotics have not shown adverse effects, have appeared safe to administer, and have even been added to
some infant formulas.