Question

Diuretics are substances that help eliminate water from the body. Few volunteers were taken into the study, all of which had same mass. They drank nothing for eight hours before the test and urinated just prior to ingesting the test substance. The three substances (water, caffeine, and salt) were tested on three separate days. The results are shown in the tables below.
Table 1

Volunteer	Amount of caffeine ingested (in 100 ml water)	Volume of urine collected after 1 hour
A	50 mg	302 ml
B	100 mg	492 ml
C	150 mg	667 ml
D	200 mg	863 ml

Table 2

Volunteer	Amount of sodium chloride ingested (in 100 ml water)	Volume of urine collected after 1 hour
A	0.9 g	201 ml
B	1.8 g	162 ml
C	2.7 g	125 ml
D	3.6 g	82 ml

Table 3

Volunteer	Volume of water ingested	Volume of urine collected after 1 hour
A	100 ml	230 ml
B	200 ml	240 ml
C	300 ml	252 ml
D	400 ml	263 ml

Which of the following substances could be classified as a diuretic?

• A. Caffeine
• B. Sodium
• C. Water
  
• D. Both A and B
  
• E. Both A and C
  

Answer 1

The correct option is E Both A and C

Diuretics are substances that cause an increase in the production of urine. In the given table 1, as the concentration of caffeine ingestion increases, volume of urine increases. Same results can be made from table 3 that is the volume of urine collected increases with the volume of water ingested but In table 2 as the concentration of sodium chloride ingested, the volume of urine decreases gradually. So, water and caffeine can be classified as a diuretic. Thus, the correct answer is 'Both A and C.'