GOS is made using a specialized process from lactose, the main carbohydrate source in milk. The name refers tp a particular part of the lactose, called galactose. Many of the hundreds of oligosaccharides (simpler, soluble carbohydrates) in breastmilk contain galactose.
GOS has several functions in digestive health and immune system of infants and children:
In one study, GOS has been reported to stabilize stool softness . GOS has also been demonstrated to boost Bifido-bacterium (good bacteria) levels and reduce Clostridium (bad bacteria) levels in the gut, while also lowering colic after 2 weeks .
In other research, GOS contributed to a drop in the likelihood of children developing respiratory infections. A GOS-containing prebiotic has been used in milk-based nutrient interventions to significantly reduce the risk of respiratory or gut infection episodes, including diarrhea and vomiting  in children up to 29 months.
This figure shows how GOS helped to reduce the percentage of kids with infection episodes by 8%, and this reduced the number of children who needed treatment by 30% (adapted from ).
A further research study has reported that the inclusion of GOS has contributed to improvements in gut motility in children up to 4 years of age .
GOS helps with lowering respiratory infections