What essential nutrient is lacking in a diet that consists solely of milk?

A diet that consists solely of milk is indeed lacking in iron, making it essential to highlight this nutrient. While milk is a good source of several nutrients, including calcium, it is relatively low in iron. Iron is critical for the formation of hemoglobin in red blood cells, which is vital for transporting oxygen throughout the body.

Exclusively consuming milk would not provide adequate amounts of this nutrient, potentially leading to iron deficiency anemia, characterized by fatigue and weakness.

In contrast, milk is rich in calcium, which supports bone health, and also contains some iodine. However, iodine levels can vary and are not the primary concern in a milk-only diet. Vitamin C, while important for immune function and skin health, is not found in significant amounts in milk. Therefore, the absence of iron in a diet composed solely of milk is the most significant nutritional gap, confirming that it is indeed the essential nutrient lacking in such a diet.