Casein and Whey are two different groups of proteins which are present in both breastmilk and cows' milk. The protein component of breastmilk is predominantly whey proteins. Whey proteins are thought to be more easily digested than casein proteins. For this reason, most infant formulas suitable from birth (starter formulas) are whey dominant (60% whey:40% casein).

Heinz Nurture® Starter Infant Formula and Heinz Nurture® Gold Starter Infant Formula are both whey dominant infant formulas with a whey to casein ratio similar to breastmilk. (60:40).

Heinz Nurture® Follow-On Formula and Heinz Nurture® Gold Follow-On Formula are casein dominant formulas. These formulas have a whey:casein ratio similar to cows' milk (20:80) which makes it slower to digest and therefore more suitable for infants over 6 months of age.