When comparing cow's milk versus breastmilk, which statement is true regarding protein content?

When comparing cow's milk versus breastmilk, which statement is true regarding protein content?

• A. Cow's milk provides less potassium and sodium
• B. Cow's milk contains a lower proportion of casein compared to whey protein
• C. Breastmilk contains less protein
• D. Breastmilk provides more calcium

Answer: (C)

The key idea here is that total protein content differs between the two milks. Human breastmilk has a lower total protein concentration than cow’s milk, with roughly 0.8–1.2 g of protein per 100 mL in breastmilk compared with about 3 g per 100 mL in cow’s milk. This lower protein amount in breastmilk is appropriate for an infant’s growth and kidney function, while still providing essential amino acids in a form that’s easy to digest. The other statements aren’t about protein content: minerals like potassium and sodium aren’t the focus here; in cow’s milk the dominant protein is casein, with relatively little whey compared to human milk, which has a higher whey-to-casein ratio; and calcium content is a mineral matter, not a protein measure, so it doesn’t support the claim about protein.

The key idea here is that total protein content differs between the two milks. Human breastmilk has a lower total protein concentration than cow’s milk, with roughly 0.8–1.2 g of protein per 100 mL in breastmilk compared with about 3 g per 100 mL in cow’s milk. This lower protein amount in breastmilk is appropriate for an infant’s growth and kidney function, while still providing essential amino acids in a form that’s easy to digest. The other statements aren’t about protein content: minerals like potassium and sodium aren’t the focus here; in cow’s milk the dominant protein is casein, with relatively little whey compared to human milk, which has a higher whey-to-casein ratio; and calcium content is a mineral matter, not a protein measure, so it doesn’t support the claim about protein.