Which of the following are defining characteristics of vitamins?
A. They yield approximately 4 kcal per gram.
B. Prolonged absence of the compound from the diet produces deficiency symptoms.
C. Chronically excessive consumption of the compound produces toxicity symptoms.
D. The body is unable to synthesize enough of the substance to maintain health.
The Correct Answer and Explanation is:
The correct answer is B, C, and D.
Explanation:
Vitamins are essential organic compounds required in small quantities for a variety of biological functions. They are distinct from macronutrients like carbohydrates, proteins, and fats in several ways. Let’s break down the options:
- A. They yield approximately 4 kcal per gram.
This statement is incorrect. Vitamins do not provide calories. While carbohydrates, proteins, and fats supply energy in the form of kilocalories (kcal), vitamins do not serve as a significant energy source. Vitamins are involved in facilitating metabolic processes but do not directly contribute to caloric intake. - B. Prolonged absence of the compound from the diet produces deficiency symptoms.
This statement is correct. A defining characteristic of vitamins is that they are essential nutrients. When a particular vitamin is absent or insufficient in the diet, the body cannot function optimally, leading to deficiency symptoms. For example, lack of vitamin C leads to scurvy, and a deficiency in vitamin D causes rickets or osteomalacia. Vitamins play critical roles in immune function, metabolism, and cellular processes, and a deficiency in any of them can lead to a range of health issues. - C. Chronically excessive consumption of the compound produces toxicity symptoms.
This statement is also correct. Although vitamins are needed in small amounts, excessive intake—especially of fat-soluble vitamins like A, D, E, and K—can lead to toxicity. Overconsumption of certain vitamins can accumulate in the body and cause harmful effects. For instance, too much vitamin A can lead to liver damage, and excess vitamin D can result in hypercalcemia. - D. The body is unable to synthesize enough of the substance to maintain health.
This is true for many vitamins. While some vitamins, like vitamin D, can be synthesized by the body with the help of sunlight, most vitamins must be obtained from the diet because the body cannot produce them in sufficient quantities. For example, humans cannot synthesize vitamin C, so it must be consumed through dietary sources like fruits and vegetables.
Thus, the defining characteristics of vitamins are B, C, and D.