It has just come to my attention that a systematic review published two years ago found that probiotics help preterm infants ward off necrotizing enterocolitis. Here is a summary of the review:
Necrotizing Enterocolitis (NEC) is a serious disease that affects the bowel of premature infants in the first few weeks of life. Although the cause of NEC is not entirely known, milk feeding and bacterial growth play a role. Probiotics (dietary supplements containing potentially beneficial bacteria or yeast) have been used to prevent NEC. Our review of studies found that the use of probiotics reduces the occurrence of NEC and death in premature infants born less than 1500 grams.
The reductions in the likelihood of this disease and of death (presumably from this disease) were both greater than 50%.