Healthier Ways to Eat With Rare Kidney Disease

Receiving a diagnosis of a rare kidney disease like immunoglobin A nephropathy (IgAN), can be a lot to process. Thoughts of what your new normal will be like and what aspects of life are still in your control are understandably common.

“Diet and lifestyle changes are first and foremost. They are not emphasized enough in my opinion,” says Anjay Rastogi, M.D., Ph.D., a professor and the clinical chief of nephrology at UCLA Health in Los Angeles.

IgA nephropathy happens when clumps (or complexes) of abnormal antibodies build up in the kidneys and cause damage to the organ’s small filters that flush out fluid and waste. One of the key components of managing kidney disease is adjusting one’s diet, which can lead to quite a long list of foods, ingredients, and minerals to avoid.

Here, we went to dietitians who specialize in working with people managing rare kidney disease to get their expert advice for eating right for IgAN.

It can be tough to follow all the eat-this-not-that guidance you might find out there with rare kidney disease. But the advice is shifting to a more holistic approach, say our experts. “Now the research is emerging that it’s more important to focus on the overall quality of the diet and whole eating patterns, rather than only individual ingredients,” says dietitian Sara Prato, R.D.N., a specialist in renal nutrition based in Colorado Springs, CO, and founder of the CKD Dietitian.

Unlike chronic kidney diseases that might arise due to diabetes or high blood pressure, IgaN is an autoimmune disease that increases inflammation. So the first recommendation that Prato usually gives to the newly-diagnosed is to shift to an anti-inflammatory style of eating like the Mediterranean diet.

“It’s well-known and supported by research for its abilities to lower the risk of cardiovascular disease and help with weight loss and blood sugar management,” says Prato. The key food groups of the diet include fruits, vegetables, beans, nuts, whole grains, lean proteins like fish, and olive oil.

One of the biggest strengths of the Mediterranean diet for people with IgAN is the prevalence of omega-3 fatty acids, which have anti-inflammatory properties. Fish are among the best sources of omega-3s—especially salmon, cod, halibut, and tuna— according to the Cleveland Clinic’s Renal Diet, which suggests adding fish to meals two to three times a week.

Because the kidneys have to work harder to remove protein waste, eating a lot of protein daily can wear them out faster. “A higher protein diet can lead to worse kidney performance over time versus more moderate diets,” says Leslie F. Thomas, M.D., a nephrologist at the Mayo Clinic in Phoenix, AZ. “For any person with IgA nephropathy who is at significant risk for developing decreased kidney function over time, we do recommend a moderation of dietary protein intake of 0.8 grams [gm] of protein per kilogram of body weight per day. This is regardless of age.” That amount is the same recommendation as for a sedentary person under 40, but less than the 1 to 1.2 gm recommended for the average adult over 40, per the Mayo Clinic.

For a 165-pound adult, the 0.8 grams formula for those with IgAN translates to roughly 60 gm of protein per day. That might look like having one cup of plain Greek yogurt (19 gm) with a cup of fruit (1 gm) for breakfast, a salad with one cup of quinoa (6 gm) for lunch, and a four-ounce salmon filet (28 to 32 gm) with a cup of steamed vegetables (2 to 3 gm) for dinner. There are exceptions to the low-protein approach, and that includes patients with IgAN and diabetes and/or weight issues such as obesity.

“With those with sugar metabolism concerns (e.g., with diabetes mellitus), great concern is made with regard to where calories will be accrued,” says Dr. Thomas. “If protein is lowered, then either sugar or fat will have to rise for weight to be maintained. Needless to say, in such cases (which are not rare), we often seek dietitian consultation so that patients can come up with a concrete dietary plan.” As a higher weight can also be detrimental to kidney health, “in such cases, we do everything we can to work with these patients to support continued maintenance of a healthful weight on a lowered protein intake,” adds Dr. Thomas.

(Dietary recommendations are also adjusted based on other IgAN comorbidities, such as hypertension, cardiovascular disease, and digestive issues like celiac disease.)

While lean meats like chicken and turkey fall into the healthier protein category, moving away from animal meat may further benefit people with kidney disease. In fact, some studies have found that plant proteins can actually reduce a person’s risk of developing kidney disease in the first place.

“Plant proteins are lower in protein and higher in fiber than animal products,” explains Lauren Budd Levy, R.D.N., a renal dietitian based in Summit, NJ, and the owner of Happy Healthy Nutrition.

Plant proteins are also rich in calcium, magnesium, and potassium, which have been associated with lower dietary acid load. People with kidney disease have a harder time removing acid from the blood, and that can impact everything from muscle mass to bone density. A higher alkaline diet helps people with kidney disease balance their pH levels, according to the American Kidney Fund.

Not all plant-based foods are alike, however, and patients will want to avoid some of the overprocessed options increasingly filling grocery stores. “Watch out for highly processed vegetarian meats: They often contain added sodium and potassium and have similar protein content to meat,” says Levy. Instead, she recommends those with IgAN—as well as those with the rare kidney disease complement 3 glomerulopathy (CG3)—look for whole foods like beans, nuts and seeds, legumes, tofu, and tempeh.

One complication of IgAN can be high blood pressure. Because sodium can cause your body to retain more water, this can further increase blood volume—and therefore raise blood pressure. As a guideline, the IgA Nephropathy Foundation recommends an ideal limit of no more than 1,500 milligrams (mg) of sodium per day—which is only three quarters of a teaspoon of salt. That’s 800 mg less than current U.S. Dietary Guidelines for average Americans, which caps sodium at 2,300 mg a day.

Reading labels is key, says Prato. The Centers for Disease Control and Prevention (CDC) points to 10 popular foods that contribute to 40% of the sodium we consume in a day, like bread and rolls, cold cuts/cured meats, pizza, poultry, soups, sandwiches, cheese, pasta mixed dishes, meat mixed dishes, and savory snacks.

Also, “people often choose meat substitutes when adopting a plant-based diet, but many of these products can be high in sodium,” says Levy, who is also an author of Cukebook, a nonprofit resource that provides culinary and nutritional guides for people with IgAN and other kidney diseases. “Instead, opt for low-sodium or no-salt-added beans, nuts, legumes, or tofu.”

For something basic like bread, Prato points clients to the options that have less than 140 mg of sodium, at least 3 gm of fiber, no phosphorus additives, and less than 5 gm of added sugar per slice. A few brands that fit the bill: Dave’s Killer Bread, Ezekiel, and Oroweat.

Still, it’s worth noting that not everyone needs to follow a low-salt diet. “In some people, high salt intake doesn’t seem to lead to high blood pressure, but others are more salt sensitive. It depends on your phenotype,” says Dr. Thomas. Your doctor can work with you to determine whether salt is an issue for your particular situation.

Our experts explain the issues that the nutrients potassium and phosphorus might pose for your kidneys and what the current thinking is on consuming them.

Potassium

It used to be that everyone with kidney disease, including people diagnosed with IgAN, received a low potassium prescription. That’s because kidney disease makes it difficult for kidneys to filter out excess potassium, and it builds up in their blood, potentially leading to muscle weakness and heart issues. People would then Google and discover that high potassium foods include a whole bunch of fruits and vegetables—such as leafy greens, root vegetables, oranges, and bananas—the exact categories of food that people are typically encouraged to consume more of.

Today, instead of ruling out high-potassium foods altogether, nutritionists are more likely to look at lab tests and adjust diets accordingly. “It’s important to know what your potassium level is and why,” says Prato. “Not everyone has to have a low-potassium diet. And some might have really high levels of potassium, but it could be due to medications or constipation.”

The role of plant foods is also no longer viewed as the culprit it once was. A 2022 review of the research studies in the Journal of Renal Nutrition found that the correlation between dietary potassium and hyperkalemia (high potassium in the blood) “is small to nonexistent,” and the researchers concluded that “whole, unprocessed plant foods should not be restricted to the extent that they have been in the ‘renal diet’”—or the older guidelines. Another study supported the same findings and reassured health care providers that “plant-based diets are an important tool for prevention and management of [rare kidney disease].“

If your potassium levels are too high or too low, Prato recommends adjusting portion sizes and the types of fruits and vegetables to improve lab numbers. Things like dried fruit, juices, smoothies, and sauces from fruits and vegetables can have high potassium concentrations, so consumption of those should be more limited.

Phosphorus

While it usually doesn’t become an issue until the later stages of kidney disease, phosphorus is another mineral that can build up in the blood and cause problems when the kidneys stop working. A common ingredient that is often not listed on food labels, it can “hide” in additives that begin with “phos.” Animal protein including dairy can contain a lot of phosphorus, and it’s more likely to be absorbed by the system than plant protein, says Prato.

Per the Cleveland Clinic, it’s best to limit dairy to 1 cup of milk or one yogurt per day. But a lot of the healthy vegetables also need to be limited to once a week, including broccoli, mushrooms, and Brussels sprouts. Other healthy foods that contain phosphorus are bran and wheat cereals, oatmeal, and granola.

Prato suggests that those with IgAN have their potassium and phosphorus levels checked regularly. She adjusts her IgAN clients’ diets in order to keep these levels safe. If necessary, your doctor might also adjust your medications to better control your blood potassium and phosphorus levels.

Living with a rare kidney disease such as IgAN or CG3 takes having to make some dietary changes to do what’s best for your condition. But don’t become scared eatless by what you read via Google: Talk to your doctor about which of these broad-stroke strategies are beneficial for you and what your particular test results mean for fine-tuning your eating habits.

Also consider working with a dietitian who can help create a customized meal plan for you and make adjustments based on your condition. “This includes evaluating overall kidney function by examining labs such as creatinine, estimated glomerular filtration rate (eGFR), and protein levels in urine, as well as monitoring nutrient levels like potassium, sodium, and phosphorus,” says Prato. Ask your doctor for recommendations or try searching on the Academy of Nutrition and Dietetics Renal Practice Group.

As IgAN is a chronic illness, focusing on diet is a lifelong commitment, one which you should make with the support of your care team. “You’re going to have these people in your life for a long time,” says Prato. “Make sure you have a good supportive team, and be open and honest with them.”