Among the major nutrients listed, milk is considered a relatively poor source of which vitamin or nutrient in a normal human diet?

Introduction / Context:
Milk is often described as a nearly complete food because it contains proteins, fats, carbohydrates, vitamins, and minerals. However, it is not perfectly balanced for all nutrients, and some vitamins are present only in small amounts. This question examines your knowledge of which nutrient milk is a poor source of, an important point in basic nutrition and general science used in many competitive exams.

Given Data / Assumptions:
- Milk is known to supply various nutrients including calcium, protein, and carbohydrates. - The options list calcium, protein, vitamin C, and carbohydrates. - We assume normal cow's milk as commonly consumed by humans. - We must select the nutrient for which milk is relatively deficient compared with other food sources.

Concept / Approach:
Cow's milk is rich in calcium, which supports bone and tooth health. It also provides high-quality protein and a significant amount of carbohydrates in the form of lactose. However, milk has only very small amounts of vitamin C (ascorbic acid); it is not considered a good source of this vitamin. Humans typically need to obtain vitamin C from fruits and vegetables. The approach is therefore to choose the option that represents vitamin C as the nutrient in which milk is poorest.

Step-by-Step Solution:
Step 1: Consider calcium. Milk is famously recommended for calcium intake because it contains a high concentration of this mineral, so milk cannot be a poor source of calcium. Step 2: Consider protein. Milk contains complete proteins like casein and whey, making it a valuable source of high-quality protein. Step 3: Consider carbohydrates. Milk contains lactose, a disaccharide, which contributes significant carbohydrate calories to the diet. Step 4: Now consider vitamin C. While milk has trace amounts of vitamin C, the quantities are small compared with what is found in citrus fruits, berries, and many vegetables. Step 5: Nutritional science frequently notes that milk is a poor source of vitamin C; infants and adults alike need additional vitamin C-rich foods. Step 6: Therefore, among the options, vitamin C is the correct choice for the nutrient that milk poorly supplies.

Verification / Alternative check:
Standard nutrition tables show that a typical serving of milk provides considerable calcium (often 200 milligrams or more per glass), several grams of protein, and carbohydrates from lactose. However, the vitamin C content is very low, especially after processing and storage. Dietary guidelines often mention that while milk can help meet many nutrient requirements, vitamin C must be obtained primarily from fruits and vegetables. This confirms that vitamin C is the correct answer.

Why Other Options Are Wrong:
Calcium is one of the first nutrients associated with milk and dairy products; they are recommended specifically to meet daily calcium needs. Protein intake from milk and milk products plays a major role in growth, particularly in children. Carbohydrates in the form of lactose make milk an energy-dense food. Because milk is a good source of these three, none of them can be the correct answer to the question about a poor nutrient source. Only vitamin C fits the description of being relatively lacking in milk.

Common Pitfalls:
Students may sometimes think that milk must be poor in carbohydrates because it does not taste as sweet as sugary drinks, but lactose still contributes significantly to energy intake. Others might be confused by the idea that milk is a complete food and may assume it has all vitamins in abundance. Remembering that milk is low in vitamin C and that scurvy prevention relies on fruits and vegetables will help you quickly identify vitamin C as the nutrient for which milk is a poor source.

Final Answer:
Milk is a relatively poor source of vitamin C (ascorbic acid).