When creatinine levels rise, this could signal a problem with kidney function. Creatinine -- a waste product of muscle activity found in the blood -- is removed from the body via the urine after the kidneys filter it out of the blood. The creatinine test is widely used as a measure of kidney function, but elevated levels can also be influenced by hydration, body muscle mass or certain medications. If your creatinine level is above the normal range, have your doctor evaluate the reason. If it is related to kidney disease, changing some dietary habits might help lower your creatinine level and reduce your risk of kidney failure.
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A common recommendation for lowering creatinine is to reduce intake of dietary protein, particularly when kidney disease is present. Creatinine is formed through a series of metabolic reactions that occur as protein is broken down into amino acids, and from the breakdown of the muscle component creatine, which is also found in meat. Thus, higher amounts of dietary protein can increase creatinine in the blood and it is believed that limiting high protein foods such as meat, poultry, fish, milk and cheese may help lower creatinine levels. However, the significance of temporary changes in creatinine levels is unclear because research has been more focused on how diet impacts progression or worsening of kidney dysfunction -- a condition marked by permanent elevations in creatinine levels. A review published in the September 2005 issue of "Nutrition and Metabolism" concluded that there is insufficient evidence to show that people without kidney disease are harmed by a high protein diet. Nevertheless, current evidence suggests that people with pre-existing kidney disease may benefit from reduced dietary intake of protein.
The impact of fiber on creatinine levels has recently been the subject of research. According to a November 2014 review article published in the "European Journal of Clinical Nutrition," researchers concluded that dietary fiber could lower creatinine levels. The researchers hypothesized that the mechanism behind this may be fiber's ability to aid in the breakdown of creatinine before it reaches the kidneys. Fiber is found in fruit, vegetables, whole grains, nuts, seeds and beans. If kidney function is already impaired, adding fiber to the diet can pose challenges because these high fiber foods are naturally high in potassium and phosphorus, and in some people with advanced kidney failure, these nutrients also need to be restricted in the diet. So it's important for anyone with kidney disease to receive ongoing education and nutrition therapy from a dietitian who specializes in kidney disease.
Fluids and Medications
If you are dehydrated, creatinine levels may be higher because your blood is more concentrated. If this is the suspected cause of your abnormal test result, your doctor may recommend drinking more water and repeating the test. Certain medications can also raise creatinine levels, some by causing dehydration and others by increasing creatinine production or retention in the body. Intense exercise, because it causes muscle breakdown, can also lead to higher levels. Finally, the use of creatine supplements can lead to temporary elevations in creatinine, according to a spring 2012 review in "The Permanente Journal." If medications or supplements are the cause, your doctor will advise changes as necessary.
Warnings and Precautions
If you have a high creatinine level or any concerns about your kidney function, consult with your doctor for accurate interpretation of your blood test results and for treatment recommendations. If elevated creatinine levels are due to impaired kidney function, restricting dietary protein and increasing fiber intake may help, but any dietary changes should be made under the recommendation of your doctor. Work with a dietitian who specializes in kidney disease to assist with meal planning to ensure all nutrient needs are met and that any changes in diet are geared towards improving kidney function and decreasing health complications.
Reviewed by: Kay Peck, MPH, RD
REFERENCES & RESOURCES
- Cochrane Database of Systematic Reviews: Low Protein Diets for Chronic Kidney Disease in Non Diabetic Adults
- European Journal of Clinical Nutrition: Dietary Fiber Effects in Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Controlled Feeding Trials
- National Institute of Diabetes and Digestive and Kidney Diseases: Chronic Kidney Disease: What Does It Mean for Me?
- American Journal of Kidney Disease: Effect of a High-Protein Diet on Kidney Function in Healthy Adults: Results From the OmniHeart Trial
- Nutrition and Metabolism: Dietary Protein Intake and Renal Function
- The Permanente Journal: False Estimates of Elevated Creatinine
- Clinical Chemistry: Normal Reference Values for Creatine, Creatinine and Carnitine Are Lower in Vegetarians