Renal Care Management: Protecting and Maintaining Kidney Function Through Dietary Choices
Can patients eat their way to better kidney health, lower their overall risk of chronic kidney disease and its main comorbidities, or slow its progression?
When kidneys are damaged or diseased, they progressively lose the ability to filter waste from the bloodstream. The more waste that builds up, the harder the kidneys must work, resulting in a progressive loss of function.
That’s why Healthmap Solution’s (Healthmap) Care Navigation teams include licensed dietitians with training and experience specific to chronic kidney disease (CKD) management. Alongside a patient’s lead Care Navigator, the dietician’s role is to educate patients on the impact food choices have on kidney function and help them make choices that will help minimize further kidney damage and slow or stop the disease’s progression.
This is an especially important role in light of a groundbreaking study  recently presented at ASN Kidney Week 2022. The study, presented by its lead author, Deidra C. Crews, MD, ScM, a professor of medicine at Johns Hopkins University School of Medicine, addressed one of the major social determinants of health faced by socially and economically disadvantaged patient populations: knowledge gaps about healthy eating and shopping within a budget. The study showed that coaching on choices and purchasing led to significant improvements in diet quality and albuminuria. This is what Healthmap Care Navigators and dietitians do for all our members.
What constitutes a kidney-friendly diet? What should CKD patients consume and what should they avoid, and why? Will adopting a kidney-friendly diet be of value in managing other comorbidities?
The relationship between diet and CKD is complex and eating recommendations must be based on individual factors, including a patient’s age, weight, gender, disease stage, comorbidities, and so on. However, there are steps all CKD patients should take and several well-established diet plans that will help them maintain kidney health.
The following steps are drawn from an article  on the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) website.
Choose and prepare foods with less salt and sodium
Salt and sodium contribute to high blood pressure, damaging the microtubules that perform the kidneys’ filtration function. NIDDK recommends less than 2,300 milligrams of sodium per day. To reduce sodium/salt intake, patients should:
- Cook meals from scratch using fresh foods. Avoid fast foods, frozen dinners, canned foods, etc. which are typically higher in sodium. Restaurant foods tend to be high in sodium as well. Choose salt-free or low-sodium options, if available.
- When buying packaged foods, check the Nutrition Facts label for sodium content. A Daily Value of 20 percent or more means the item is high in sodium.
- Use spices, herbs, and sodium-free seasonings instead of salt.
Rinse canned vegetables, beans, meats, and fish with water before eating.
Eat the right amount and the right types of protein
Protein is necessary for building or maintaining muscle mass and repairing disease damage. It also helps regulate phosphate levels. But eating protein produces waste that the kidneys must remove. Eating more protein than needed puts increasing stress on the kidneys. Therefore, protein intake should be moderated.
Protein is derived from meat, dairy, and plants. Which is best? According to the National Kidney Foundation’s Journal of Renal Nutrition: 
“A recent study conducted on low protein diets in nondialysis kidney disease patients suggests 50% protein intake from complete protein sources such as dairy and animal sources and 50% intake from vegetarian sources. This approach allows for optimal protein intake to prevent catabolism while preserving kidney function in early phases of chronic kidney disease.”
How much is enough? That depends. According to the American Kidney Fund: 
“The amount of protein you should eat depends on your body size, activity level, and health. Your doctor or dietitian may have you limit protein or change the type of protein you eat. For example, you may need to eat more lean proteins, which are foods that are high in protein and low in fat, such as whole eggs and skinless chicken and turkey.”
Choose heart-healthy foods
Cardiovascular disease is one of the two predominant CKD comorbidities, the other being diabetes. Therefore, it is important for CKD patients to choose foods that keep fat from building up in their heart, blood vessels, and kidneys, such as:
- Lean cuts of meat
- Poultry without the skin
- Low-fat or fat-free dairy
In preparing meals, they should:
- Grill, broil, bake, roast, or stir-fry foods; avoid deep-frying
- Cook with non-stick cooking spray or a small amount of olive oil instead of butter
- Trim fat from meat, remove the skin from poultry
- Limit foods with saturated and trans fats
The following steps apply to patients with late-stage CKD:
- Choose foods and drinks with less phosphorus
Failing kidneys can allow phosphorous to build up in the bloodstream. Too much phosphorous can pull calcium from bones, weakening them. Elevated levels of phosphorous can also cause itchy skin, and bone and joint pain. Therefore, patients should consume foods that are low in phosphorous. These include:
- Fresh fruits and vegetables
- Breads, pasta, and rice
- Corn and rice cereals
- Light-colored sodas (e.g., lemon-lime) and homemade iced tea
However, some foods that tend to be high in phosphorous are also necessary sources of protein: meat, fish, poultry, dairy, beans, and nuts. Here again, a qualified nutritionist/dietitian should be consulted when appropriate to find the right balance.
- Choose foods with the right amount of potassium
Damaged kidneys also allow potassium to build up in the bloodstream. This can impair nerve and muscle function and lead to serious heart problems. Food and drink choices can help lower potassium levels if required. To avoid higher levels of potassium, patients should:
- Check with their doctor or dietitian about using salt substitutes. Some can be very high in potassium.
- Drain canned fruits and vegetables before eating.
The American Kidney Fund  also suggests that CKD patients may want to limit their fluid intake:
“This is because damaged kidneys do not get rid of extra fluid as well as they should. Too much fluid in your body can cause high blood pressure, swelling, and heart failure. To limit fluids, you will need to cut back on how much you drink and limit eating some foods that contain a lot of water, such as soups, ice cream, gelatin, and many fruits and vegetables.”
The Mediterranean Diet
It is possible to provide patients with a renal management diet that also helps with other comorbidities, particularly diabetes and cardiovascular disease. One of them is the well-established and documented Mediterranean Diet. In fact, the European Renal Association-European Dialysis and Transplantation Association now recommends it as the diet pattern of choice for CKD patients.
Features of the Mediterranean Diet include:
- High consumption of fruits, vegetables, bread and whole-grain cereals, potatoes, beans, nuts, and seeds
- Use of extra virgin olive oil as a source of monounsaturated fat
- Low to moderate consumption of dairy products, fish, and poultry
- 0-4 eggs consumed per week
- Very few sweets
- Lower red-meat consumption, mainly in connection with special occasions
- Low to moderate wine consumption during meals
Observed benefits of the Mediterranean Diet, first reported in the 1950s, include a lower risk of cardiovascular disease and a reduced incidence of obesity and Type 2 diabetes. Another benefit is that it is well-supported with numerous published cookbooks and online recipe sources.
For more, see the journal article  “Mediterranean Diet as the diet of choice for patients with chronic kidney disease,” published by Nephrology Dialysis Transplantation.
The DASH Diet
The DASH Diet (“Dietary Approaches to Stop Hypertension”) is promoted by the National Heart, Lung, and Blood Institute of the National Institutes of Health (NIH). Similar in many ways to the Mediterranean Diet, the DASH Diet focuses on fruits, vegetables, whole grains, and lean meats, and restricts red meat, salt, added sugars, and fats. As the Mayo Clinic [6} further explains:
“The DASH diet includes foods that are rich in potassium, calcium, and magnesium. These nutrients help control blood pressure. The diet limits foods that are high in sodium, saturated fat, and added sugars.
“Studies have shown that the DASH diet can lower blood pressure in as little as two weeks. The diet can also lower low-density lipoprotein (LDL or “bad”) cholesterol levels in the blood. High blood pressure and high LDL cholesterol levels are two major risk factors for heart disease and stroke.”
Secondary benefits include the potential for weight loss and a lower risk of cancer. The diet has also been linked to a lower risk of type 2 diabetes; some studies indicate that it can improve insulin resistance as well. Research also points to an 81% lower risk of metabolic syndrome, a cluster of conditions that occur together and increase the risk of heart disease, stroke, and type 2 diabetes.
Like the Mediterranean Diet, the DASH Diet is also well-supported with cookbooks and recipes, in print and online.
While diet plans like these can be highly beneficial, individual circumstances must be weighed in helping patients make appropriate food choices. Qualified advice and coaching have been shown to make a significant difference in outcomes, especially in economically and educationally disadvantaged patient populations.
Healthmap Solutions and our experienced Care Navigation teams stand ready to help.
We Are Champions for better kidney disease management. We Are Healthmap!