EWG's Guide to Infant Formula and Baby Bottles: Powdered is better

BPA has been detected in every brand of liquid formula, but powdered formulas have not yet been tested. While most formula containers produced in the United States contain some BPA in the lining, we found significant differences in BPA leaching potential of liquid and powdered formulas. Our modeling suggests that powdered formulas are a better choice for babies.

We modeled three factors that determine BPA leaching potential from different types of formula containers and concluded that liquid formulas have 8 to 20 times higher potential BPA leaching than the most common powdered formulas due to smaller can sizes and the fact that the product is less diluted with water.

Even if the same amount of BPA leached from coated metals in powdered and liquid formulas, babies fed powdered formula will receive less BPA than those fed liquid formula from metal cans

Four factors govern the amount of BPA leaching from different types of formula in metal cans:

• The amount of surface area coated with BPA. Enfamil and Similac use BPA on the metal top and bottom lids of their package, approximately 30% of the container. Earth’s Best Organic, PBM/Store Brands and all liquid formula use cans with 100% BPA lining. Nestlé claims to use no BPA in their packaging but it is unclear what they use instead.
• The volume of the container. Smaller containers have a higher surface-to-volume ratio which results in potentially higher concentrations of BPA in the product than larger containers.
• How much the product is diluted with water. For powdered formula, parents mix about 34 grams of powdered formula with 8 ounces (226 grams) of water, meaning about 13% of the bottle contents came from the can. For concentrated liquid formula, parents mix with an equal amount of water, diluting the contents of the can by 50%. Ready-to-eat formulas are not diluted with any water.
• The heat intensity of the canning process. Studies measuring BPA levels in liquid formula find that the actual amount of BPA is variable, probably due to differences in the can and the processing. Since there is no available information on the BPA content of powdered formulas, we assumed that BPA is equally likely to leach from the plastic surfaces of a powdered or liquid formula can.

Our calculations also assume that parents are using bottles that don't leach any BPA into formula.

Using Enfamil and Similac cans with 30% BPA coating as the baseline we found that 100% metal cans of powdered formula (used by Earth's Best and PBM) have 3 or 4 times higher leaching potential depending on the can size. But the real difference is comparing the leaching potential of liquid and powdered formulas. The maximum leaching potential was from ready-to-eat formula in smaller 8 oz. cans. These types have the highest BPA contact per unit surface area and are not diluted with any water prior to feeding. These formulas have an estimated 21-times more BPA leaching than the most popular types of powdered formulas.

Provided that BPA leaches equally from liquid and powdered formulas during processing, powdered formulas are a better option for babies. Parents should also be advised to buy formula in the largest size available and to choose concentrated rather than ready-to-eat liquid formulas.

∗∗This formula was used as a baseline when comparing the potential BPA leaching from other types