Question

Which of the following is not secreted in urine?

• A. Niacin
• B. Ascorbic acid
• C. Cholecalciferol
• D. Thiamine

Answer 1

Answer: (C)

Vitamins may be fat soluble, e.g., vitamins A, D, E and K, or water soluble, e.g., vitamins B-complex, C and P. Water soluble vitamins dissolve easily in water. They are easily broken down and excreted by the body. They are not stored for future use. Excess water soluble vitamins which are not stored by the body are generally excreted in urine. On the other hand, fat soluble vitamins dissolve in fat before they can be absorbed into the bloodstream. They are not normally excreted in urine. Niacin (vitamin $B_3$), ascorbic acid (vitamin C) and thiamine (vitamin $B_1$) are water soluble vitamins, and are excreted in urine. Cholecalciferol (vitamin $D_3$) is a fat soluble vitamin and therefore does not get excreted in urine.