What causes protein in urine?
Protein in urine, known medically as proteinuria, is usually a sign of kidney damage. Healthy kidneys should only filter tiny (trace) amounts of protein into the urine as they filter waste from the blood. When the kidneys are damaged, abnormal amounts of protein leak through the filters and into the urine.
Some common causes of proteinuria include:
- Diabetes – Uncontrolled high blood sugar levels can damage the kidneys over time.
- High blood pressure (hypertension) – Uncontrolled high blood pressure puts extra strain on the small blood vessels in the kidneys, causing damage.
- Glomerulonephritis – Inflammation of the tiny filters in the kidneys that filter waste from the blood.
- Kidney infection (pyelonephritis) – Bacterial infections of the kidneys can cause scarring and damage.
- Heart failure – Poor pumping function of the heart causes fluid buildup and pressure in the kidneys.
- Lupus – An autoimmune disorder that commonly affects the kidneys.
- Certain medications – Drugs like NSAIDs, antibiotics, chemotherapy, and some diuretics can damage the kidneys.
- Multiple myeloma – Cancer of plasma cells in the bone marrow that produces abnormal proteins toxic to the kidneys.
Proteinuria may also be seen temporarily after strenuous exercise, with fever, stress, or cold exposure. This benign form is known as “transient proteinuria” and goes away when the triggering factor is removed.
When to see a doctor
See your doctor if you have signs or symptoms of protein in urine, including:
- Foamy, frothy urine
- Swelling in the hands, face, abdomen, ankles, or feet
- Fatigue
- Nausea and vomiting
- Shortness of breath
- Itchy skin
Your doctor can check for protein in the urine with a simple dipstick test performed on a urine sample during an office visit. They may also recommend additional urine and blood tests to determine the cause and severity of proteinuria.
How is proteinuria treated?
The treatment for protein in urine depends on the underlying cause. If an infection, medication side effect, exercise, or temporary stress is responsible, then proteinuria will clear up on its own once the trigger is removed.
For chronic proteinuria caused by diabetes, hypertension, autoimmune disorders, or kidney damage, treatment focuses on controlling the underlying disease. Steps may include:
- Lowering high blood glucose levels through diet, exercise, medication, or insulin therapy
- Controlling high blood pressure with medications like ACE inhibitors or ARBs
- Prescribing drugs to reduce protein loss and slow kidney damage like ACE inhibitors or ARBs
- Treating related conditions such as high cholesterol or swelling
- Tailoring the diet to be low salt and low protein
In some cases, immune-suppressing drugs may be used to control disorders like lupus or glomerulonephritis. Dialysis or kidney transplant may be necessary if kidney failure occurs.
The earlier proteinuria is caught and treated, the better the chances of preventing serious kidney disease.
Lifestyle changes to reduce proteinuria
Making certain lifestyle modifications can also help control proteinuria associated with diabetes, hypertension, or CKD:
- Control blood sugar – Keep blood glucose levels in the target range by monitoring regularly, adhering to your medication regimen, and sticking to a diabetic diet.
- Lower blood pressure – Check blood pressure often and take medicines as prescribed to keep levels below 130/80 mmHg.
- Lose excess weight – Losing even a small amount of extra weight can help reduce proteinuria.
- Restrict sodium – Limit salt to 2,300 mg per day to reduce fluid retention and kidney strain.
- Limit protein – Stick to the daily amount of dietary protein recommended for kidney disease (0.6-0.8 g/kg/day).
- Stop smoking – Smoking constricts blood vessels, further impairing kidney function.
- Stay hydrated – Drink water regularly to stay well hydrated, being careful not to excessively increase fluid intake.
Following an overall healthy lifestyle with a kidney-friendly diet, physical activity, and stress management can support kidney function.
What foods help manage proteinuria?
Adjusting the diet can be beneficial when dealing with proteinuria and kidney disease. Recommended foods include:
- Fresh fruits and vegetables – Provide vitamins, minerals and fiber with less potassium than dried fruits.
- Whole grains – Choose whole grain breads, pastas, cereals and rice for fiber.
- Low-fat dairy – Milk, yogurt and cheese are good sources of protein and calcium, but limit to 2 servings daily.
- Skinless poultry – Chicken and turkey contain high-quality protein that is easier on kidneys than red meat.
- Fish – Cold water fish like salmon and tuna have heart healthy omega-3 fats.
- Eggs – A good source of protein low in sodium, phosphorus and potassium.
- Olive oil – Provides healthy fats and vitamin E.
- Apples, cranberries, blueberries – Their antioxidants help fight inflammation and damage.
- Onions, garlic – Compounds may help control blood pressure.
- Green tea – The flavonoids have anti-inflammatory effects.
Foods that are high in sodium, potassium and phosphorus should be limited as they can put extra strain on the kidneys. Examples include processed foods, baked goods, nuts, dried beans and lentils, and colas. Consult with a renal dietitian to plan the optimal dietary changes for your condition.
Conclusion
Proteinuria is commonly the result of uncontrolled diabetes or high blood pressure injuring the kidneys over time. Catching it early and getting the underlying condition properly managed are essential to preventing kidney disease progression. Medications, healthy lifestyle changes, and adjusting the diet to be kidney-friendly can all help reduce protein loss in the urine. With proper treatment, kidney function may stabilize or even improve in some cases of proteinuria. Regular follow up care with both a primary care doctor and nephrologist are recommended.
| Cause | Mechanism | Treatment |
|---|---|---|
| Diabetes | High blood sugar damages blood vessels in kidneys | Control blood sugar through diet, exercise, medication |
| Hypertension | Increased pressure in blood vessels strains kidneys | Lower blood pressure with medications |
| Glomerulonephritis | Inflammation damages filters in kidneys | Immunosuppressants, ACE inhibitors |
| Kidney infection | Bacteria directly invade and inflame kidney tissue | Antibiotics, treat underlying cause |
When to see a doctor for proteinuria
Consult your physician promptly if you notice signs of protein in urine such as foamy or tea-colored urine, swelling, fatigue, nausea, shortness of breath, or itchy skin. Proteinuria can be an early warning sign of kidney damage. The sooner it is detected and treated, the better the outlook for kidney health.
Tips for reducing proteinuria
– Monitor blood glucose regularly and keep levels in target range
– Check blood pressure often and take medications as prescribed
– Lose excess weight if overweight
– Limit sodium to 2,300 mg daily
– Restrict protein to 0.6-0.8 g/kg/day
– Stay well hydrated with water
– Quit smoking and limit alcohol
– Include fruits, vegetables, whole grains, and low-fat dairy
– Avoid processed foods high in sodium
Kidney-friendly foods for proteinuria
– Fresh fruits like apples, berries, citrus fruits, melons
– Non-starchy vegetables – greens, carrots, broccoli, squash
– Whole grains – oats, brown rice, quinoa, whole wheat pasta
– Skinless poultry
– Fish high in omega-3s
– Eggs
– Olive oil
– Low-fat milk, cheese, plain yogurt
– Limit: nuts, beans, lentils, potatoes, bananas, avocados, dried fruits