Which physiological mechanism primarily regulates sodium balance in the body?

A. Intrinsic factor enhances vitamin B12 storage: Intrinsic factor is for absorption, not storage.

B. Due to the lack of intrinsic factor, vitamin B12 cannot be absorbed: This is the definition of the pathology in pernicious anemia—the failure to absorb B12 due to missing intrinsic factor.

C. Intrinsic factor is destroyed by liver enzymes: Intrinsic factor functions in the intestines and is not processed by the liver in this manner.

D. Excessive excretion of vitamin B12 in urine: The issue is a failure to get the vitamin into the blood in the first place, not a loss through the kidneys.

A. Add fluid and fiber to the diet: This is the first-line, non-pharmacological intervention. Fiber adds bulk to the stool, and fluid keeps it soft, facilitating easier passage.

B. Avoid gas-producing foods: This might reduce bloating or flatulence, but it does not treat the underlying cause of constipation.

C. Request that the provider prescribe a stool softener: While a stool softener may be used, the nurse should first prioritize lifestyle and dietary interventions before relying on medications.

D. Promote active range-of-motion activities: While general mobility helps with peristalsis, fluid and fiber are more specific and effective interventions for chronic constipation.