Can high cholesterol alone cause low kidney functions?

Yes, very possible: High cholesterol over long period of time can cause atherosclerosis/narrowing of the arteries. If the renal arteries are involved, kidney functions sure can be adversely affected. The high cholesterol effects are serious--heart attacks/strokes can be devastating/fatal, so it is good to keep it down with diet/exercises, and maybe med if too high. Consult doc. Good luck.

Not likely.: It is not likely to diminish kidney function by itself, but it might eventually lead to atherosclerosis which could ultimately stop blood flow if really bad and make the kidney(s) ischemic reslting in loss of function. This may not be common as atherosclerosis that bad would affect the heart and other organs first. Things like hypertension and diabetes are likely to affect the kidneys sooner.