Which of the following is NOT a phosphate binder?

The correct response is that Vitamin B12 is not a phosphate binder. Phosphate binders are medications used in the management of hyperphosphatemia, which is an elevated level of phosphate in the blood, commonly seen in patients with chronic kidney disease or those on dialysis. Their primary function is to reduce the absorption of dietary phosphate from the gastrointestinal tract.

Renagel, Phos-Lo, and Tums are all recognized phosphate binders. Renagel (sevelamer) and Phos-Lo (calcium acetate) specifically bind phosphate in the digestive system, helping to lower the levels of phosphate in the blood. Tums, which is primarily a calcium carbonate supplement, also acts as a phosphate binder by binding dietary phosphate when ingested, thus reducing its systemic absorption.

In contrast, Vitamin B12 does not have a role in binding phosphate or affecting phosphate levels. It is a vital nutrient that supports red blood cell formation and neurological function, unrelated to phosphate management. Therefore, it is clear why Vitamin B12 is not considered a phosphate binder in this context.