Which of the following group of vitamins is fat-soluble? (Choose the most…

Vitamins are classified as fat-soluble or water-soluble based on how the body absorbs and stores them. Fat-soluble vitamins dissolve in dietary fats, are absorbed into the body along with fat through the intestinal wall, and get stored in the liver and fatty tissues, so they do not need to be consumed every day. Water-soluble vitamins dissolve in water, are absorbed directly into the bloodstream, and are mostly excreted through urine rather than stored, so they need more frequent replenishment.

There are only four fat-soluble vitamins: A, D, E and K. This is commonly remembered with the mnemonic ADEK. All four require dietary fat and bile for proper absorption in the small intestine, and because they accumulate in body tissue, excessive long-term intake can lead to toxicity, unlike most water-soluble vitamins.

• Vitamin B and B-complex: every B-complex vitamin (B1, B2, B3, B6, B9, B12, etc.) is water-soluble, so this group is not fat-soluble.

• Vitamin C and D: this pairs a water-soluble vitamin (C) with a fat-soluble vitamin (D), so the group as a whole is not fully fat-soluble.

• Vitamin B and E: this pairs a water-soluble vitamin (B) with a fat-soluble vitamin (E), so the group as a whole is not fully fat-soluble.

Only the group Vitamin A, D, E and K consists entirely of fat-soluble vitamins, so it is the correct answer.