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The Truth About Protein
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By Maria Karalis, MBA, RD, LDN
People who have been diagnosed with chronic kidney disease (CKD) often find themselves confronted with many lifestyle changes, with diet being one of the most challenging. But there are steps that can be taken to help delay the start of dialysis. This article briefly reviews the components of a CKD diet with the primary goal to maintain optimal nutrition. There is no “one-size-fits-all” diet. Your diet needs to be individualized based on your kidney function, other medical conditions, and nutritional status. A CKD diet is a complex diet and the goals are to reduce the risk of malnutrition, delay the need for dialysis, and, when you do start dialysis you will start at a healthier state and live longer. To reduce the risk of muscle wasting and malnutrition, see a diet and nutrition expert or a Registered Dietitian (RD) for individualized counseling. The RD will provide you with a tailored meal plan which includes how many servings you need from each food group to maintain optimal health. Protein – To restrict or not? Since the landmark MDRD (Modification of Diet in Renal Disease) study published in 1994, the debate continues with respect to the role of protein in delaying the progression to chronic kidney disease. It is possible that flawed study designs may account for the mixed results. However, several meta-analysis have been published that indicate a small beneficial effect[1]. Today, most experts agree that dietary protein should be controlled especially during stages 3 and 4 of CKD (GFR between 60 and 15 ml/min/1.73 m2). A protein restriction helps to decrease the toxins in the blood, improves phosphorus levels, improves your response to insulin, reduces the protein in the urine, and results in better blood pressure control. Protein is needed by the body to keep your tissues healthy and replace old or damaged tissue. Each day protein must be included in your diet for you to be stay healthy. When your kidneys no longer “filter” or clean your blood well enough, waste products build up from the foods we eat. The amount of protein allowed will depend on several things including your body size, stage of CKD, and other medical conditions. The amount recommended is generally around 0.6 to 0.8 grams of protein per kilogram body weight. Those at nutritional risk or diabetic will be prescribed a little bit more protein. For example, if you weigh 150 pounds, that is 68 kilograms. Therefore, you are allowed anywhere from 40 to 54 grams of protein per day (.6 x 68 and .8 x 68). Protein is found everywhere in the foods we eat (see table 1). There are small amounts of protein in breads, fruits, and vegetables, but the majority of the protein is found in meats, chicken, fish, eggs, and dairy products. There are two kinds of protein: high quality protein (animal protein from meats, chicken, fish, eggs, and dairy products) and low quality protein (plant protein from vegetables, breads, cereals). You need at least 50% protein from high quality sources. The RD can figure out your needs to include a mixture of these proteins. The RD can tell you exactly how many ounces of meat, chicken, fish, or eggs you can have each day. Generally speaking, one ounce of meat, chicken, or fish contains 7 grams of protein. Meat or other protein should always be weighed without bone or shell after cooking. Table 1: Protein content in Food Groups Food Group | Amount of Protein per serving (grams) | Milk | 4 grams per ½ cup | Meat, Fish or Chicken | 7 grams per 1 ounce | Breads | 2 grams per serving* | Vegetables | 1 gram per serving* | Fruits | 0.5 gram per serving* | Fats | No protein |
[1] Kaisiske BL, Lakatua JD, et al: A meta-analysis of the effects of dietary protein restriction on the rate of decline in renal function. Am J Kid Dis 31: 954-961, 1998. *Servings vary depending on food item. Calories The right amount of calories is needed for your body to use the proteins for growth and repair. Calories are necessary for energy and for maintaining your body weight. If you don’t eat enough calories, your body will break down muscle protein for energy. Just as fuel gives power to cars, calories fuel your body and give you energy. If you are underweight, the RD will give you suggestions on how to increase calories in your diet. You also may be asked to take a special liquid nutrition supplement for people with CKD to boost your calorie intake. Phosphorus Research has shown that phosphorus tends to speed up the loss of kidney function. Phosphorus is found in almost all foods we eat 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 snacks (it works by binding to phosphorus from the foods you eat). Binders can be taken right before, during, or after meals or snacks. Usually milk is limited because it contains too much phosphorus. If you are a milk drinker, don’t worry…there are milk substitutes on the market that you can use. Some products include Coffee-Mate, Coffee-Rich, Mocha Mix and DariFree. Potassium Potassium is a mineral important for regulating your heart. Limiting potassium is generally not necessary at this stage of CKD. The amount of potassium allowed will be individualized based on your potassium level in your blood. If you are taking a “water pill” or diuretic such as Lasix, you may need to take a potassium supplement. Fluid Limiting your fluid intake is usually not needed at this time. But as your kidney function slows down, you make less urine and fluids will build up in your body. When this occurs, you may experience edema – swelling of the hands, feet, or stomach. This water weight may cause shortness of breath. At this point, your doctor may ask you to cut back on your fluid intake. Sodium How much sodium you can have each day depends on the type of kidney disease you have, blood pressure, edema, urine output, and the condition of your heart. Regardless of the type of kidney disease you have, do not use a salt substitute. Salt substitutes contain potassium and can increase the level of potassium in your blood. Check with your nephrologist first before using any salt substitute. Vitamins You may require a special vitamin to replace water-soluble vitamins. Ask your dietitian about this. 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. It is important to see a Registered Dietitian to determine YOUR individual needs. Breakfast (12.5 grams of protein) ¾ cup cornflakes, ½ cup nondairy creamer, 1 banana, 1 slice toast, 1 soft-cooked egg, 2 tsp. margarine and coffee with sugar or sugar substitute Lunch (18.5 grams of protein) Roast Beef Sandwich (2 ounces of roast beef, 1 tsp mayonnaise, 2 slices bread, 1 small tomato sliced), ½ cup Fruit cocktail in heavy syrup 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 1 medium apple, lemonade Snacks throughout the day or evening (4.5 grams of protein) ¾ ounce pretzels 3 graham crackers 1 fresh pear or 1 medium apple Blood Pressure High blood pressure or hypertension damages the blood vessels in the kidneys. This decreases the blood supply to the kidneys. It is recognized as both a cause and a result of chronic kidney disease. High blood pressure also increases your risk of cardiovascular disease. Optimal blood pressure for those people with CKD and diabetes should be less than 130/80 according to the 7th Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (Hypertension 2003; 43: 1206-1252). It is important to have regular checkups with your doctor to check for high blood pressure. Diabetes Diabetes is currently the number one cause of CKD. But there’s good news. Today, with good care, fewer than 10% of people with diabetes develop kidney failure. High blood sugar levels cause changes in the function of the blood vessels in the kidney. Over time, this causes destruction of the nephrons or “filters” of the kidneys (nephrons are the working units of the kidneys, removing wastes and extra fluid from the blood). Work closely with your doctor and RD to manage your diabetes. Also, ask your doctor about taking medication to slow down kidney damage. Two kinds are available: ACE (angiotensin converting enzyme) inhibitor or ARB (angiotensin receptor blocker). Chronic Kidney Disease – A Silent Disease Have your kidneys checked at least once a year by having your urine tested for small amounts of protein (microalbuminuria test). You should also have your blood tested at least once a year for serum creatinine. The result of this test should be used to estimate your glomerular filtration rate or GFR, the “gold standard” measurement for kidney function. Most don’t experience any signs and symptoms of kidney disease until CKD is advanced. If you experience worsening of these symptoms, see your doctor right away: Change in how often you urinate Edema or swelling of the face, feet, or stomach Loss of appetite Nausea or vomiting Dry, itchy skin Very tired or weak Headaches Inability to concentrate, confusion Muscle cramping at night
Anyone can develop CKD at any time. Some people are more likely than others to develop kidney disease, particularly those who have diabetes, high blood pressure, family history of CKD, are older, or those who belong in these population groups: African Americans, Hispanic Americans, Asian, Pacific Islanders, and American Indians. Medical Nutrition Therapy (MNT) When treatment for a medical condition includes nutrition advice, health care providers use the term medical nutrition therapy (MNT). Medical Nutrition Therapy, when provided by an RD, has been shown to improve outcomes of persons with chronic conditions. The right diet can delay the start of dialysis and reduce your risk of cardiovascular disease. Many insurance policies cover MNT when recommended by a doctor. If you qualify for Medicare, you can receive the MNT benefit from an RD when your doctor provides a referral indicating that you have diabetes or chronic kidney disease. Medicare covers 80% of the Medicare-approved amount for MNT after you have paid the $100 deductible for Part B services. One way to locate a qualified RD is to go to the American Dietetic Association website at www.eatright.org. Go to “Find a Nutrition Professional” in the upper right hand corner of the page. Users can enter their state or zip code and a list of RD’s in that area will appear. To narrow the search, select “Renal (kidney) nutrition” in the expertise field. Conclusion There is a lot you can do to slow down the damage to your kidneys and delay the need for dialysis: Keep your blood pressure under control if you have high blood pressure. Keep your blood sugar under control if you are diabetic. Get a referral for a Registered Dietitian. If you are on Medicare, ask about Medical Nutrition Therapy. Keep your appointments with your primary care doctor, nephrologist, and RD. With regular visits, problems can be found sooner and managed appropriately.
About the Author Maria Karalis, MBA, RD, LDN, is a Nutrition Consultant and Writer and has worked in the nephrology field for 19 years. She enjoys writing for healthcare professionals and people with chronic kidney disease (CKD) with one goal in mind: helping CKD patients live their life to the fullest. This article has been updated to reflect the latest research and was originally published on the iKidney.com website, supported by Watson Pharma, Inc.
[1] Kaisiske BL, Lakatua JD, et al: A meta-analysis of the effects of dietary protein restriction on the rate of decline in renal function. Am J Kid Dis 31: 954-961, 1998.
Last Updated January 2010
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