Which vitamin-like nutrient is neither fat-soluble nor water-soluble and is sometimes called a provitamin?

• A. Choline
• B. Inositol
• C. Carotenoids (e.g., beta-carotene)
• D. Biotin

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the classification of nutrients based on their solubility. Vitamins and vitamin-like nutrients are generally classified as either fat-soluble (such as vitamins A, D, E, and K) or water-soluble (such as vitamin C and the B-complex vitamins).
2. Step 2: Recognize that some compounds are called provitamins because they can be converted by the body into active vitamins. For example, beta-carotene is a provitamin that the body converts into vitamin A.
3. Step 3: Identify the nutrient that does not fit neatly into the fat-soluble or water-soluble categories but is still vitamin-like and acts as a provitamin. Carotenoids, such as beta-carotene, are known for this property.
4. Step 4: Compare the options given: Choline and Inositol are water-soluble vitamin-like nutrients, Biotin is a water-soluble vitamin, but Carotenoids are unique because they are neither strictly fat-soluble nor water-soluble and serve as provitamins.
5. Step 5: Conclude that the correct answer is Carotenoids (e.g., beta-carotene) because they are vitamin-like nutrients that are neither fat-soluble nor water-soluble and function as provitamins.