By Angelo P. Capozzoli, RD, CSR, LD

It is estimated over two-thirds of chronic kidney disease (CKD) cases were caused by diabetes or hypertension, two chronic illnesses with strong nutritional aspects to their management. Obesity is a major factor in type 2 diabetes and weight loss can help control blood pressure. Decreasing salt intake also helps control blood pressure and the need for additional or higher doses of medication. Since the kidneys control blood pressure, most patients with CKD develop hypertension, even if they didn’t have it before.

The Centers for Disease Control and Prevention (CDC) consider CKD and diabetes (primary cause of CKD) a public health problem. (1) CKD now costs Medicare $49 billion dollars a year and is increasing, putting a significant financial strain on future generations. Fortunately, there are steps we can take to prevent the onset and progression of CKD. Since each patient responds differently to their health condition and medications can affect nutritional needs/restrictions, a doctor can write an order for a diet and refer you to a qualified dietitian. This article covers the relationship between nutrition and CKD. It is not a substitute for a consultation with a registered dietitian (RD).

Medicare and many insurance companies pay for visits with a RD. Besides diet, it is important to see your doctor regularly and take all medications prescribed. Certain blood pressure medications your doctor prescribes can help protect the kidneys. Also, ask your doctor about exercise.

Protein restriction, it has been argued, could slow the progression of CKD and help relieve symptoms of advanced CKD known as uremia. However, protein restriction can also lead to malnutrition. There’s a careful balancing act patients must adhere to. Too much protein can also lead to high levels of phosphorus and potassium, which CKD patients must keep a close eye on. Once on dialysis, protein intake should be increased, but to prevent the progression of CKD, the focus should be on controlling conditions that cause progression: diabetes and hypertension. Weight and carbohydrate control can help manage or prevent the onset of diabetes. For hypertension management and prevention, weight as well as sodium control should be the focus. Fat intake can play a role with many patients because the cardiovascular disease risk is 10-30 times greater in patients with CKD. Some causes of CKD have little relation to diet, but once diagnosed, diet is an important part of therapy.

Sodium increases blood pressure and is a “fluid magnet.” Reducing salt helps reduce diuretic (water pills) use, which can make patients get up at night to urinate and stay home during the day for fear of wetting themselves. It can also reduce the need for other blood pressure medications.

Restaurant food is often high in sodium, and thirst is your body’s way of trying to get rid of it. Even eating many family recipes will cause this thirst. Just because you don’t add salt to your foods doesn’t mean you’re not preparing foods high in sodium. We’re not born with a hunger for salt, it is learned. It is what I call your “family dictionary.” Now is the time to start a legacy of healthy eating that generations can follow. Reducing salt a little at a time will reduce your need to use it. Some spices are a good substitute for salt. Besides, just think, eventually you could enjoy the natural flavor of food, not the taste of salt! What a novel idea!

Phosphorus must be restricted in most advanced CKD patients. High phosphorus can cause heart, lung and bone problems, and lead to amputations. Since many foods have phosphorus, your doctor may prescribe phosphate binders. High phosphorus food lists are readily available. They include: What I call “grazing,” snacking on a bowl of popcorn while watching television, is an unhealthy habit. If you’re hungry, eat a snack, take your binders and be done with it. Besides, the more times you eat, the greater the chance of forgetting your binders.

Potassium restriction may or may not apply to you. Diuretics and peritoneal dialysis can cause low potassium, making it necessary to take potassium supplements. Some blood pressure medications can raise potassium but protect the kidneys, so they are prescribed. It is important to remember the poison is in the dose. Just because a food is low in potassium doesn’t mean you can eat all you want. The most common foods that have potassium are produce, some salt substitutes, most dairy products and meat. High or low potassium can be life threatening. If your potassium is low, your life could be at risk if you develop nausea, vomiting or diarrhea. Make sure you contact your doctor in this case.

There are other nutritional components to the care of kidney patients that cannot be discussed in the scope of this article. This information is readily available on the Internet. A renal dietitian has the time to discuss issues such as vitamin needs, recommended calcium intakes and how the medications you take affect your nutritional status. There are also CKD courses that are taught by many providers. Ask you doctor about these resources. Knowledge can help you take control of your life!

Reference:

_{United States Renal Data System - Atlas of CKD; Five: Cost of Chronic Kidney Disease, http://m.usrds.org/1_ckd/05_costs.aspx.}

Angelo P. Capozzoli, RD, CSR, LD, is the president of Southeast Clinical Nutrition Centers, Inc., an Atlanta practice of registered dietitians who help people manage their chronic diseases through medical nutrition therapy (MNT) and lifestyle changes. Capozzoli is also president of Renal Reserve, a dialysis staffing agency.

This article originally appeared in the May 2009 issue of Kidney Beginnings: The Magazine.

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