Nephrotic syndrome occurs when the glomeruli in the kidney become damaged, and instead of filtering properly, they allow too much protein to spill into the urine. Nephrotic syndrome symptoms include foamy urine due to the protein spilling, fluid retention, low blood albumin levels, swelling, eye puffiness, high blood pressure, and elevated cholesterol levels. Though the syndrome is rare, it affects both adults and children.
To treat nephrotic syndrome, your medical team will likely prescribe medication, but they also might recommend diet changes. Learn more about the typical diet recommendations for nephrotic syndrome below.
Diet changes for nephrotic syndrome
Although what you eat and drink doesn't cause nephrotic syndrome, diet changes help control the syndrome's symptoms. After a diagnosis of nephrotic syndrome, people often receive instructions to monitor their sodium, fluid, protein, and fat intake.
As always, the information below is intended for adults in general, and you should check with your own medical team if you're unsure whether these changes are right for you. Children may have stricter diet guidelines or a different management approach, so check with a child's medical provider or pediatric nephrologist for specific nutrition recommendations.
Sodium
Controlling your sodium (salt) intake may help lower your blood pressure and reduce swelling, and is often a key part of the diet for nephrotic syndrome. Ask your medical team for a specific recommendation, but try to stick to 2000 milligrams (mg) or less if you're not sure where to start. A single teaspoon of salt contains about 2300 mg of sodium, so reducing sodium might be a significant change for you at first.
To reduce sodium intake, avoid adding salt to your food after it’s cooked and minimize the amount of salt you use during cooking. Reduce the amount of packaged and processed foods you eat, and always check the nutrition labels of packaged foods and drinks to see how much sodium is in each serving.
Foods with more salt than you might expect include:
- Chips and packaged popcorn
- salted nuts and seeds
- cookies and other baked goods
- packaged soups and sauces
- processed meats (meat sticks, jerky, canned meats, sausages)
- soy sauce
- frozen dinners
- convenience foods
Whenever possible, cook from scratch and use fresh herbs or a low-sodium seasoning blend for meats and side dishes. For a crunchy snack, choose unsalted seeds, nuts, or popcorn. Restaurant food is often very high in sodium, so try to avoid eating out when you can, or choose a small portion of the entree and fill up on fresh fruits or unseasoned vegetables on the side.
Fluid
Since nephrotic syndrome causes swelling (edema), you may have a fluid restriction, especially if your eyes or legs are puffy and swollen.
Reducing your salt intake should help control your thirst somewhat, but if you find that you're still too thirsty on the recommended amount of fluid, try these tips:
- Use a smaller glass, and take smaller, spaced-out sips instead of drinking the cup all at once.
- If you're having trouble keeping track, use a bottle or cup marked with ounces or milliliters to stay on top of how much you drink at a time.
- Keep your cup in the other room so you can't drink mindlessly.
- Savor a few ice cubes or chips instead of grabbing a glass of liquid.
- Keep a few hard candies nearby to help stimulate saliva production if your mouth feels too dry.
- Try sucking on a lemon or lime wedge to quench your thirst.
Remember that popsicles, soup, broth, jello, and shakes also count towards your fluid limit.
Protein
Avoid a high-protein diet. Although the protein (albumin) in your blood is low when you have nephrotic syndrome, eating a high-protein diet won't help increase the protein in your blood and could make things worse.
Most adults need only about 0.8 grams of protein per kilogram of body weight to meet their basic protein needs. To calculate your weight in kilograms, divide your weight in pounds by 2.2. Then, multiply by 0.8 to find your daily protein needs. It's probably much lower than you would expect. For example, a 180-pound person needs about 65 grams of protein per day.
Remember that poultry, meat, and fish aren't the only sources of protein. Protein-rich foods also include milk, yogurt, cheese, nuts, tofu, beans, and lentils.
Most of us eat more protein at a meal than we need, doubling or tripling the intended serving size of meats and fish. In general, aim for about 3-4 ounces of protein at a meal, which is about the size of a deck of cards, or the palm of your hand. For thinner fish, such as tilapia, the serving size is about the size of a checkbook.
Protein content of common foods:
- 4 oz chicken breast: ~35 grams (g)
- ⅙ of a Spam container, or 2 oz: 7 g
- 2 small breakfast sausages: 9 g
- 4 oz fresh tuna: ~28-30 g
- 1 egg: 6 g
- 1 cup/8 oz soy or cow's milk: 7 g
- 5-6 ounces Greek yogurt: 12-20 g
Heart-healthy diet
Nephrotic syndrome can lead to hyperlipidemia, which means you have too many lipids, or fats, in your blood. Hyperlipidemia includes elevated cholesterol and triglyceride levels. You may need medication to lower blood fats, but choosing heart-healthy fats in your diet and avoiding less healthy fats is also recommended.
Heart-healthy fats include:
- Liquid vegetable oils: olive, canola, soy, safflower, sunflower
- Fatty fish: tuna, salmon, sardines
- Avocados
- Walnuts
- Flax seed
Limit these fat sources:
- Fried foods
- Fatty cuts of meats
- High-fat dairy (cream, butter, whole milk)
- Processed meats (sausages, hot dogs, brats)
- Pastries and baked goods
- Cooking with animal fats such as lard and bacon grease
Bottom Line
If you have nephrotic syndrome, changing your diet may help. Ask your medical team about diet and fluid restrictions and how long you need to follow them. If you need help with a personalized approach and plan that meets your individual needs, reach out to a registered dietitian, especially one specializing in renal issues and kidney disease.
