By Maria Karalis, MBA, RD, LDN

You’ve heard it before: one in nine adults has chronic kidney disease (CKD) and another 20 million are at increased risk for developing it and don’t even know it. Moreover, nine in ten people with kidney disease have seen a doctor within the previous year, but only about one-third of them knew their kidneys were failing.

There are steps that can be taken today to help prolong your kidney function. The top two reasons for CKD are diabetes and high blood pressure. Keeping your blood pressure and blood sugars under control are important in slowing damage to your kidneys. Following a special diet is another way you can help to slow this damage and delay the need for dialysis.

Research has been done on low protein diets and the progression of kidney disease but the results are not conclusive. In some types of kidney disease, strict blood pressure and blood glucose control and a low protein diet have been shown to help. It is important to ask your nephrologist (kidney doctor) to refer you to a registered dietitian (RD) for individualized nutrition counseling. An RD will provide you with a specific meal plan that includes the right types and amounts of food. The meal plan will be individualized based on your kidney function, other medical conditions and nutritional status. Following a pre-dialysis diet without seeking nutrition counseling by an RD can lead to malnutrition.

This article provides dietary guidelines to help you take an active role in maintaining your kidney function. The goal of this diet is to maintain optimal nutrition.

Protein and Calories

Each day, protein must be included in your diet for you to stay healthy. Protein is needed by the body to keep your tissue healthy and replace old or damaged tissue. It also is needed to fight infections and keeps your body fluids in balance.

When your kidneys no longer “filter” or clean your blood well enough, waste products build up from the foods you eat. When this happens, you will feel tired and may have a poor appetite. By eating less protein, your kidneys will work less since there is less waste to filter, thus preserving the function of your kidneys.

You simply cannot omit all protein in your diet – your body still needs enough protein to build and repair body tissue. The amount of protein allowed each day depends on how well your kidneys work and your body size. As these change, your diet may also change. For instance, if you receive a kidney transplant or start dialysis, your diet will change.

The amount of protein prescribed is typically around 0.6 to 1.0 grams per kilogram desired body weight. Those at nutritional risk or diabetic will be prescribed a little bit more protein. For example, if you weigh 150 pounds (68 kilograms), you are allowed anywhere from 40 grams of protein per day to 68 grams per day (0.6 x 68 and 1.0 x 68).

Protein is found everywhere in the foods we eat (see table). There are small amounts of protein in breads, fruits and vegetables but the majority of protein is found in meats, chicken, fish, eggs and dairy products. There are two kinds of protein: high quality (animal protein from meat, chicken, fish, eggs and dairy products) and low quality (plant protein from vegetables, breads and cereal). You need at least 50 to 60 percent protein from high quality sources.

The RD can tell you exactly how many ounces of meat, chicken, fish or eggs you can have each day to include a mixture of these proteins. Generally speaking, one ounce of meat, chicken or fish contains 7 grams of protein. Meat or other protein should always be weighed after cooking and without the bone or shell. A piece of cooked meat the size of a deck of cards equals 3 protein servings or 3 ounces of meat.

In order for your body to use protein for growth and repair, the right amount of calories is needed. Calories are necessary for energy and maintaining your body weight. Because you are getting fewer calories from protein, you will need to get more calories from other types of foods. This is very important to maintain your weight and protect your muscle tissue (otherwise, your body will break down its own muscle for energy). In order to get enough calories, you will need to eat more fats and carbohydrates. This is probably different from what you are used to eating.

 Protein Content in Food Groups

*Servings vary depending on food item.

 Stretching Out Your Protein

Make sure to stretch out your protein intake. In other words, don’t eat all of your protein at one time. This makes your kidneys work harder. Start thinking of vegetables and grains as the main dish and meats as the side dish.

Here are some tips in creating meals that won’t seem like you are eating less protein:

• Slice your meats very thin; this will spread them out to look like a bigger portion.

• Fill up sandwiches first with lettuce, cucumber, chopped celery, apple, parsley or water chestnuts. Then use thinly sliced meat.

• Make entrees with small pieces of meat or chicken. Mix in with extra rice or pasta.

• For casseroles, use less meat than the recipe calls for and replace it with more rice or your favorite pasta.

• Use stronger tasting cheeses – a little bit of them goes a longer way. Try sharp cheddar, feta or Romano.

The National Kidney Foundation has additional information on modifying recipes. Visit their Web site www.kidney.org and check out “Enjoy your own recipes using less protein.”

Phosphorus

Research has shown phosphorus tends to speed up the loss of kidney function. Phosphorus is found in almost all foods but is especially high in protein foods. Other foods high in phosphorus include milk, cheese, nuts, seeds, bran, chocolate, colas and legumes such as pinto beans and kidney beans. If your phosphorus level in your blood is high, you may be asked to take a medication known as a “phosphate binder.” This medication should be taken with meals and binds to phosphorus from the foods you eat.

Potassium

Potassium is a mineral important for regulating your heart. Limiting potassium is generally not necessary at this early stage of CKD. The amount of potassium allowed will be individualized based on your potassium level in your blood. It is best to avoid salt substitutes that contain potassium chloride. These can cause your blood potassium to become too high.

 Fluid

Limiting your fluid intake is usually not needed at this time. However, keep in mind when your kidney function slows down further (closer to needing dialysis), you make less urine and fluids build up in your body. When this occurs, you may experience edema where your hands, feet or stomach swell. You will gain water weight and may feel short of breath. If this happens, call your doctor right away.

 Sodium

How much sodium you are allowed depends on the type of kidney disease you have, your blood pressure, fluid status, urine output and the condition of your heart. Most likely, if you are reading this you are already following a low sodium diet and know to limit foods very high in sodium such as convenience foods (TV dinners, canned/dried soups and deli meats), fast foods and processed meats/cheeses. Cook foods without salt and remove the salt shaker from your dinner table.

Label Reading and Sodium

Read the nutrition labels carefully and buy food with less sodium. Overall sodium levels in processed foods have been reduced through better technology and the introduction of other preservatives. Over the last 20 years, food manufacturers have made reduced- and low-sodium versions of many of their products.

Check out the differences in these products:

• 2 ounces canned tuna (310 mg sodium) versus 2 ounces low sodium canned tuna (135 mg sodium)

• 3 ounces ham (1030 mg sodium) versus 3 ounces lean pork loin (75 mg sodium)

• 1/2 cup canned green beans (70 mg sodium) versus 1/2 cup frozen green beans (5 mg sodium)

On the food label, look for ingredients that contain any of these words: Na, salt, soda (as in sodium bicarbonate) or sodium. Even everyday medications, such as antacids and headache remedies, contain sodium and must be labeled if the amount is more than 5 milligrams per dose, according to the American Heart Association.

Buy products with less than 20 percent of the daily recommended sodium intake per serving. A product with less than 5 percent of the daily value per serving is considered low sodium. Check out the portion size. One serving of soup may contain 480 milligrams of sodium or 20 percent of the daily value. But if you eat the entire can you'll have consumed 40 percent of the daily value! 

Sample Meal Plan*

The following is a sample meal plan providing approximately 50 grams of protein, 1800 calories and 1800 mg of sodium.

*This is just a sample menu. It is important to see a registered dietitian to determine YOUR individual needs based on your medical condition.

Breakfast (12.5 grams of protein)

¾ cup cornflakes, ½ cup nondairy creamer, a banana, one slice toast, a soft-cooked egg, 2 tsp. margarine, and coffee with sugar or sugar substitute

Lunch (18.5 grams of protein)

Roast beef sandwich (2 ounces roast beef, 1 tsp. mayonnaise, two slices bread, a small tomato sliced), ½ cup fruit cocktail in heavy or light syrup, and iced tea (regular or diet) with lemon

Dinner (15.5 grams of protein)

2 ounces sautéed steak, ½ cup carrots, 4 tsp. margarine, ½ cup applesauce or a medium apple, lemonade

Snacks throughout the day or evening (4.5 grams of protein)

¾ ounce pretzels, three graham crackers, and a fresh pear or medium apple

Other Early Complications of CKD

As kidney function declines, the kidney no longer makes enough hormones like erythropoietin (EPO) or calcitriol. EPO stimulates the bone marrow to make red blood cells. Less EPO means less blood cells or a low blood count, also known as anemia. Be sure to have your hemoglobin levels checked to see if you are anemic. Your kidney doctor may prescribe medication to treat your anemia.

In those with CKD, the kidneys make very little calcitriol or active form of vitamin D. Due to low levels of calcitriol, the kidneys are not activated to reabsorb calcium or phosphorus and the amount of calcium and phosphorus in the blood gets out of balance. Eventually, this imbalance causes your parathyroid glands to make too much parathyroid hormone, or PTH. This is called secondary hyperparathyroidism, or too much PTH in the blood.

A high PTH can affect many organs and tissues, including your bones, heart and blood vessels. It’s important to have your PTH regularly checked. If you have early CKD, your PTH may be high due to low calcitriol levels. Your calcium and phosphorus levels will probably be normal. If your PTH is high, your doctor may prescribe an active form of vitamin D to lower your PTH. You can’t get active vitamin D over the counter – only with a prescription.

Treatment of anemia and secondary hyperparathyroidism should begin early to reduce complications of cardiovascular disease.

Maria Karalis is a registered dietitian and nutrition consultant for iKidney.com. She also is the associate editor of the Journal of Renal Nutrition.

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 health care provider for appropriate care.

This article originally appeared in the March/April 2006 issue of Kidney Beginnings: The Magazine, Vol. 5, No. 1.

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