The present disclosure relates to soy protein-based powdered nutritional formulas, such as infant or toddler formulas, that contain lutein and fructooligosaccharide (FOS). The FOS stabilizes lutein present in the formula, resulting in less lutein degradation over the shelf-life of the formula. When fed to infants, the nutritional formulas provide an infant stool pattern, frequency, and color more closely resembling that of breastfed infants.