Dietary restrictions vary depending on the stage of kidney disease.
For instance, people who are in the early stages of chronic kidney disease will have different dietary restrictions than those with end-stage renal disease, or kidney failure.
Those with end-stage renal disease who require dialysis will also have varying dietary restrictions. Dialysis is a type of treatment that removes extra water and filters waste.
The majority of those in the late stages or with end-stage kidney disease will need to follow a kidney-friendly diet to avoid build-up of certain chemicals or nutrients in the blood.
In those with chronic kidney disease, the kidneys cannot adequately remove excess sodium, potassium and phosphorus. As a result, they are at higher risk of elevated blood levels of these minerals.
A kidney-friendly diet, or a “renal diet,” usually includes limiting sodium and potassium to 2,000 mg per day and limiting phosphorus to 1,000 mg per day.
Damaged kidneys may also have trouble filtering the waste products of protein metabolism. Therefore, individuals with chronic kidney disease in stages 1–4 may need to limit the amount of protein in their diets (3).
However, those with end-stage renal disease undergoing dialysis have an increased protein requirement (4).
Here are 17 foods that you should likely avoid on a renal diet.
In addition to the calories and sugar that colas provide, they also contain additives that contain phosphorus, especially dark-colored colas.
Many food manufacturers add phosphorus during the processing of food and beverages to enhance flavor, prolong shelf life and prevent discoloration.
This added phosphorus is much more absorbable by the human body than natural, animal- or plant-based phosphorus (5).
Unlike natural phosphorus, phosphorus in the form of additives is not bound to protein. Rather, it’s found in the form of salt and highly absorbable by the intestinal tract (6).
Additive phosphorus can typically be found in a product’s ingredient list. However, food manufacturers are not required to list the exact amount of additive phosphorus on the food label.
While additive phosphorus content varies depending on the type of cola, most dark-colored colas are believed to contain 50–100 mg in a 200-ml serving (7).
As a result, colas, especially those dark in color, should be avoided on a renal diet.