Clinical Nutritionist Practice Test

What factor can nutrients change that affects drug excretion?

1. Kidney filtration rate

2. Stomach pH

3. Urine pH

4. Intestinal motility

The correct answer is: Urine pH

Nutrients can indeed influence drug excretion, particularly through their impact on urine pH. The pH of urine is a crucial factor in the renal excretion of many drugs, as it can affect the ionization state of a drug. Many medications are weak acids or weak bases, and their ionization can be altered by the pH of urine, which in turn can affect their reabsorption or excretion in the kidneys. For instance, when urine is more acidic, weak bases may become more ionized and less likely to be reabsorbed by the renal tubules, leading to increased excretion. Conversely, when urine is more alkaline, weak acids may become more ionized, which could also lead to increased excretion. This dynamic highlights how dietary choices and nutrient intake—which can influence urine pH—potentially modify drug excretion processes. The other factors listed, while relevant in different contexts, do not directly correlate with the same impact that urine pH has on drug excretion. The kidney filtration rate pertains to how effectively the kidneys filter blood, but it does not directly relate to nutrient modulation or drug excretion in the same way. Stomach pH primarily affects drug absorption rather than excretion. Intestinal motility can