Let’s face it, we live in a bacterial world. As much as we’d like to protect our children from harmful germs, it’s just not possible. Most at risk are infants—especially preterm and other low-birth weight babies whose own immune system has not yet kicked in.

Protection from Birth
The best way to protect your newborn from bad bacteria is to breastfeed, which offers a host of benefits. As soon as four days old, most healthy breastfed infants have a range of beneficial bacteria, or probiotics, in the digestive tract. By contrast, one-week-old formula-fed babies enjoy no such protection. Bifidobacteria comprise between 60 to 91 percent of the total bacterial community in breastfed babies, offering greater protection against infectious bacteria than formula-fed infants have.

Healthy Strains
Premature infants given a mixture of probiotics (including B. bifidus, B. infantis, Lactobacillus acidophilus, and Streptococcus thermophilus) are less likely to develop feeding intolerance and abdominal distension, which can lead to septic shock and death. Israeli research suggests that L. reuteri helps prevent diarrhea and fever in healthy four- to ten-month-olds.

Research comparing gut flora of newborns (25 to 35 days old) in Ghana, New Zealand, and the United Kingdom finds that Bifidobacterium bifidum, B. longum, and B. pseudocatenulatum produced important immune responses in babies from the developed nations, while the African infants had mostly B. infantis. Since children in the developed world are at greater risk for atopic diseases like eczema, study authors suggest that offering them probiotics containing B. infantis might lower the incidence of these diseases.

Allergies, asthma, and other autoimmune disorders have tripled and even quadrupled in the last 50 years in industrialized countries where sanitation is commonplace. The “hygiene hypothesis” is one way to explain this rapid increase in autoimmune problems: Scientists suggest that as children grow, their exposure to bacteria actually fosters a healthy immune system. For that reason big families, daycare centers, and growing up near farm animals (where sanitation may be a little more lax) may actually help prevent these kinds of immune disorders.