Zinc Sulfate / Zinc Sulfate Monohydrate
Zinc is an essential mineral for development and organ function. The forms of zinc present in breastmilk are known to be highly absorbable, however, only present in the first three months of lactation, after which, it tapers off. The body can utilize zinc sulfate and zinc sulfate monohydrate, but to a lesser extent than the forms found in breastmilk. (Source) Zinc is a required nutrient in infant formulas, so manufacturers add zinc sulfate or zinc sulfate monohydrate to meet those minimum requirements. As with any metal-based nutrient (such as iron) too much can be harmful, but at low levels as would be added to an infant formula, it’s accepted to be safe.
If formulators are looking for naturally-occurring forms of zinc, they may be able to rely on the nutrition inherently in goat’s milk and nutritional yeast. (Source)
Potassium Bicarbonate
Potassium is a required nutrient in infant formulas; formulators add potassium bicarbonate to meet the required levels. Potassium bicarbonate is generally accepted as safe by the FDA. Of course, as with any mineral, too much can be harmful, but as used in an infant formula in low amounts it’s non-toxic and provides essential potassium.
Magnesium Phosphate
Phosphorous and magnesium are essential nutrients and are required in an infant formula. Formulators add potassium bicarbonate to meet the required levels. Magnesium Phosphate is generally accepted as safe by the FDA. Of course, as with any mineral, too much can be harmful, but as used in an infant formula in low amounts it’s non-toxic and provides essential magnesium and phoshporous.
Lutein
Lutein is a nutrient in the carotenoid family (an antioxidant related to beta carotene). It is not a nutritional requirement in infant formula; companies have added it as a nutrient to support eye health. However, the benefits of lutein-supplemented formula have not been found to be backed with evidence. (Source) It is not harmful, however, its benefits remain unproven.