High-protein diets are common among people trying to lose weight and build body muscle. As your kidneys help to filter protein from waste products, a high-protein diet forces your kidneys to work harder than normal. This extra strain can harm impaired or diseased kidneys. However, high-protein diets do not negatively affect healthy kidneys. Although generally safe for your kidneys, eating excessive amounts of protein can cause a variety of other ill health effects.
Protein foods are your only source of essential amino acids, which are the building blocks of your body's muscles and other tissues. In addition to its important role in tissue growth, maintenance and repair, protein is a source of energy. With 4 calories in every gram, protein provides the same amount of energy as carbohydrates. However, the 2010 Dietary Guidelines for Americans recommends that protein accounts for only 10 to 35 percent of your daily calories, while carbohydrates account for 45 to 65 percent.
The kidneys make up one of your body's most important filtration and detoxification systems. One of their main roles is to remove urea from your blood for excretion in your urine. As urea is a byproduct of protein metabolism, healthy kidneys are vital to your body's ability to use protein. In addition to removing urea, your kidneys work hard to keep protein in your bloodstream. Although healthy kidneys easily distinguish between protein and its wastes, damaged kidneys may remove protein and fail to remove urea from your blood.
According to the American Heart Association, most Americans regularly exceed their daily protein requirements. Despite this, most Americans do not suffer from kidney damage. As such, following a high-protein diet apparently has little impact on the health of your kidneys. However, impaired kidneys may not be able to filter out the excessive amounts of urea that stem from a high-protein diet. As such, the National Kidney and Urologic Diseases Information Clearinghouse suggests that you can extend the life of damaged or diseased kidneys by eating a low-protein diet.
MayoClinic.com states that high-protein diets typically involve carbohydrate restriction. This can lead to nutritional deficiencies and insufficient amounts of dietary fiber, potentially leading to weight gain and digestive, intestinal and cardiovascular health issues. Additional weight gain and cardiovascular problems can arise from the high total, saturated and trans fat content of many high-protein foods. You can avoid some of these issues on a high-protein diet by reducing your red meat intake and eating more fish and vegetable proteins. However, eating a balanced diet is the best way to ensure that you do not suffer from the negative impact of excessive protein intake.
- U.S. Department of Agriculture and U.S. Department of Health and Human Services; Dietary Guidelines for Americans, 2010
- National Kidney and Urologic Diseases Information Clearinghouse: The Kidneys and How They Work
- MayoClinic.com: High-Protein Diets: Are They Safe?
- American Heart Association: High-Protein Diets
Matthew Lee has been writing professionally since 2007. Past and current research projects have explored the effect of a diagnosis of breast cancer on lifestyle and mental health and adherence to lifestyle-based (i.e. nutrition and exercise) and drug therapy treatment programs. He holds a Master of Arts in psychology from Carleton University and is working toward his doctorate in health psychology.