By Cathi Martin, RD, CSR, LDN

It's a jungle out there! Anyone who has ever been on a special diet knows how difficult it is to get the right kind of foods to meet their needs. When you have chronic kidney disease (CKD), you may have as many as six different restrictions in your diet, including salt, potassium, protein, phosphorus, sugar (if diabetic) and fluid. Any one of these would be a challenge, but the complexity multiplies with each additional restriction. This article will provide info rmation on labels, terms frequently used and other useful tips to help make your trips to the grocery store a lot less frightening.

According to the Kidney Disease Quality Outcomes Initiative (K/DOQI) of the National Kidney Foundation, there are many things that you can do to slow the progression of kidney disease and a major part of that is controlling what you eat. K/DOQI recommends that a person with chronic renal insufficiency should lower protein intake significantly, but not to the point of risking malnutrition. A registered dietitian can help you determine how much protein you need and where it should come from. Depending on what other health problems you have, you may or may not need additional restrictions. Sodium is usually restricted anywhere from one to three grams to help control fluid load and blood pressure. Occasionally, you may have to watch potassium intake; however, many times diuretics are prescribed for fluid maintenance that help rid the body of excess potassium. 

Phosphorus is another area that needs careful monitoring. There is some controversy over whether or not it contributes to kidney failure, but high levels certainly can contribute to bone problems when the kidney is not functioning fully. Unfortunately, you will not find a listing of these latter nutrients on a food label since they are not a major concern to the public at large. While food labels have become more standardized and info rmational in recent years, especially in regards to sodium content, they still do not provide easy access to info rmation that is important in kidney disease.  

Potassium

Potassium may or may not be restricted in CKD. If you are taking a strong diuretic, you may actually need to increase your potassium intake through supplements or food choices. However, some diuretics and blood pressure medications "spare" potassium and therefore may allow too much to stay in your system, depending on the level of kidney failure. Potassium is even more difficult to find on food packages and requires more knowledge of food sources. It is generally more abundant in fresh fruits and vegetables and dairy products, but may turn up in many places. Canned fruits and vegetables are usually acceptable on the renal diet.

Phosphorus

When the kidneys are not working properly, calcium and phosphorus can become unbalanced. This can lead to weakened bones and may actually hasten the decline of the kidney function. Phosphorus is generally not easy to find on food labels, so it is useful to know common sources of phosphorus. However, phosphorus is usually provided as a percentage of the Daily Value (DV). The DV for phosphorus is 1,000 mg based upon a 2,000 calorie diet. Therefore, when you see the percentage, such as 15%, add a zero and the content is 150 mg per serving.  

Sodiu m

Sodium, alias salt, is fairly well defined on food labels and has specific definitions related to the terms "low sodium," "no salt added" and "reduced sodium." "Low sodium" means that there is less than 140 mg of sodium per serving for the item. "No salt added" means that there may be salt in the product, but no additional salt has been used in processing. "Reduced sodium" indicates that the product contains one-third less sodium than the original version of the same product.   

Food L abels

Ingredient lists can provide a wealth of info rmation and are required on any packaged product. They are listed in order by weight of the ingredients in the product. For instance, if the first item on the list is water, then water is the most abundant ingredient in that product. They are also required by law to indicate the types of fats used in the product.  Look for key words such as sodium, phosphate and potassium here as they are frequently used in preservatives and flavorings to help determine if this product is suitable for your diet.  

Recent regulations from the Food and Drug Administration and the Food Safety and Inspection Service of the U.S. Department of Agriculture have cleared up much of the confusion. Some of the most important changes include:  

• Health claims about the relationship between a nutrient or food and a disease that are supported by scientific evidence.

• Labels include more info rmation on the amount per serving of saturated fat, cholesterol, dietary fiber and other nutrients.

• Terms used to describe a food's nutrient content have to meet government definitions so that they mean the same for any product on which they appear.  

• Serving sizes are more consistent across product lines and are expressed in common household and metric measures rather than grams.  

• Serving sizes better reflect the amounts people really eat.  

• Nutrition labeling is now mandatory for almost all processed foods.  

General Tips  

1. Meats from the deli are usually less salty than packaged deli meats.

2. Most perishables are on the outside perimeter of the store - many high potassium foods will be in this area.

3. Portion sizes matter!  A small tangerine is okay while a 16 ounce glass of orange juice is not.

4. "Natural" or "Light" does not necessarily mean healthier.

In addition, reference books for nutrition info rmation can be purchased at your local bookstore.  "The Complete Book of Food Counts" by Corinne T. Netzer, 6th Ed (2003), by Dell Publishing ($7.99) is one of the most comprehensive and useful guides available.  The American Dietetic Association has a consumer hot line where you can speak to a registered dietitian by calling 1-800-366-1655.

It is important to remember that everyone is different and you should consult your physician for information specific to your needs. Now you are fully armed and ready to meet the challenge of the Supermarket Safari!   

Cathi Martin is a renal dietitian for the Dialysis Associates of Springfield in Nashville , Tennessee.

The information contained herein is intended for educational purposes only. It is not intended and should not be construed as the delivery of medical care. Persons requiring diagnosis or treatment, or those with specific questions, are urged to contact their local healthcare provider for appropriate care.

This article originally appeared in the September/October 2003 issue of Kidney Beginnings: The Magazine, Vol. 2, No. 3.

Back