Diet can't change creatinine levels, but it can minimize symptoms of renal failure that accompany elevated creatinine. You shouldn't rush into an unnecessarily restrictive diet without consulting your nephrologist and seeing if dietary changes are necessary. Other than eating a sensible low-sodium diet, there is no sense in prematurely limiting your diet because restrictions are often inevitable if creatinine levels are high.
Definition
Creatinine is a nitrogenous waste product produced by the breakdown of creatine. The liver produces creatine from L-arginine, glycine, and L-methionine. Muscular activity breaks creatine down into creatinine, which is removed from the bloodstream by the kidneys when they filter blood. Creatinine is a marker for kidney disease because as kidney function declines, creatinine levels increase.
Diet
As creatinine levels increase, a host of other problems arise due to the kidneys' reduced ability to clean the blood. Serum phosphorus and potassium levels rise, the pH of the blood becomes more acidic than normal and urine protein levels rise. You can alleviate many of these symptoms through your diet. As creatinine levels begin to rise, nephrologists closely monitor the blood and urine of patients and recommend dietary changes when necessary. Often a renal dietitian is called in to help the patient design a workable diet.
Potassium
Normal potassium levels are between 3.5 and 5.0 mEq/l, but levels start to edge up when kidneys no longer eliminate potassium from the blood. This condition is called hyperkalemia. The National Kidney Foundation suggests that adults limit potassium intake to between 2,000 and 3,000 mg/day. People with high creatinine who also have high potassium should avoid high potassium foods, which the NFK defines as having greater than 200 to 250 mg of potassium per serving. These include potatoes, sweet potatoes, lentils, dried beans, broccoli, tomatoes, bananas, chocolate and oranges.
Phosphorus
Normal phosphorus levels are between 3.5 and 5.5 mg/dL. These levels tend to drift up in patients with high creatinine levels. Low phosphorus diets are necessary to control serum phosphorus levels when the kidneys can no longer perform this function. High serum phosphorus levels are dangerous because the elevated phosphorus pulls calcium from the bone. Not only does this weaken bones, but it also increases serum calcium. The elevated serum calcium is deposited in blood vessels, muscles and organs. High phosphorus foods include organ meats, dairy products, legumes, peanut butter, dark sodas, lentils and beer.
References
- National Kidney Foundation: KDOQI Clinical Practice Guideline for Nutrition in Children with CKD: 2008 Update
- National Kidney Foundation: Phosphorus and Your CKD Diet
- National Kidney Foundation: Potassium and your CKD Diet
- National Institute for Diabetes and Digestive and Kidney Diseases: Chronic Kidney Disease-Mineral and Bone Disorder; February 2009
