Soy-based formulas like Similac Soy Isomil have been clinically shown to help reduce common feeding problems such asfussiness and gas when switching from milk-based formulas. Similac Soy Isomil has nucleotides for your baby s developingimmune system and prebiotics to help support the digestive system. It features an exclusive blend of DHA lutein and vitaminE important ingredients found in breast milk. Similac is the #1 infant formula brand fed in hospitals. Soy-based formulas arenot recommended for premature infants with birth weights less than 1800 g.