KIDNEY DISEASE DIET
Chronic Kidney Disease (CKD) brings many changes to a person’s life. Because the kidneys control or influence so many systems in the body, when they fail, measures must be taken to replace or make adjustments for the work kidneys normally do. This includes adjustments in the diet. Without proper nutritional monitoring by a physician and renal dietitian, a person’s health can deteriorate significantly and rapidly, causing severe illness and even death. Unfortunately, changes in dietary habits can be very difficult for many people and can pose one of the greatest challenges to those with CKD.
Certain foods must be avoided to maintain the best possible health. However, while eliminating or greatly reducing electrolytes or other food elements that are potentially harmful to someone with CKD, the person may also be eliminating essential protein, vitamins and minerals. Therefore protein, vitamin and mineral supplements are often prescribed as replacement therapy. Medicines that help patients eliminate unwanted levels of other electrolytes found in many foods are also prescribed. So the renal diet can be a difficult balancing act.
Proper nutrition for people with kidney failure is so important that each dialysis unit has a renal dietitian on the staff. The dietitian reviews each person’s blood studies regularly and is responsible for teaching patients how to adjust their diets in order to stay as healthy as possible. Certain foods may have to be limited or eliminated from the diet. People with CKD should ask their dietitian to focus on what they caneat rather than being given a long list of what they cannot eat—which can be very discouraging. It is also very helpful to have another family member present when meeting with the dietitian. He/she can clarify points by asking questions and taking notes, thus avoiding confusion about dietary recommendations. If the person with CKD is not the family chef, it is especially important to have ‘the cook’ participate in all nutrition-related discussions. The dietitian not only discusses dietary restrictions; he/she can share recipes, plan menus, offer tips for grocery shopping, and provide guidance for making wise selections at restaurants—thus helping a person to meet dietary goals.
What are some of the dietary issues that must be considered for someone with CKD?
Kidneys help to maintain the balance of fluid as well as minerals including sodium, potassium, calcium and phosphorus. The kidneys also process protein, separating it from the waste products (urea) and allowing protein to be returned to the body to help build muscle and maintain good health. When the kidneys are not working, therefore, fluid and electrolytes build up to abnormal levels and instead of protein being preserved by the kidneys’ filtering system, it spills into the urine along with waste products.
To help you understand why physicians and renal dietitians recommend certain dietary restrictions, let’s look at each of these issues one at a time.
What dietary issues are associated with fluid intake for people with CKD?
When kidneys fail, fluid builds up in the body. Fluid overload in a person with CKD can lead to serious complications. He/she gains weight from fluid retention. Swelling (edema) builds up throughout the body. It is usually first noticed in a person’s legs, feet, hands and face. Excess fluid in the blood vessels causes high blood pressure. If not adequately treated, eventually fluid can build up around vital organs including lungs (pulmonary edema(, causing shortness of breath, the belly (called ascites), and heart, making it difficult for the heart to pump the extra volume around the body. This situation puts a person at risk for congestive heart failure and even death.
Even though dialysis treatments remove excess fluid, people must still watch their fluid intake in between treatments because all fluid ingested remains in the body until the next treatment.
When a lot of excess fluid must be removed during a dialysis treatment, total treatment time may have to be extended in order to attain a person’s ‘dry weight.’ The person may experience a sudden drop in blood pressure causing dizziness, and perhaps severe cramping, nausea, and vomiting.
This scenario certainly drives home the point that it is very important to follow the medical team’s advice about restricting fluid! Ignoring the restrictions can make dialysis treatments painful and even dangerous.
What is meant by a person’s ‘dry weight?
Although ‘dry weight’ is not a precise measurement, it is generally defined as “the lowest weight a patient can tolerate without the development of symptoms or hypotension. This is the weight that physicians try to achieve by prescribing dialysis treatments to remove all excess fluid from the body—along with unwanted toxins. If dry weight is not achieved at each dialysis treatment—or worse yet, a person skips treatments—too much fluid can accumulate throughout the body, causing complications from fluid overload such as those described above.
So, what categories of foods are considered fluids?
You may be surprised to hear some of the foods in this category. Any food that is liquid at room temperature is considered to be a fluid. So, in addition to the obvious things like water and other beverages, this would include foods such as:
- Ice cream/sherbet
- Sauces and Gravies
Na Sodium (chemical symbol Na), or salt, is a very important mineral in the body as it plays a key role in maintaining fluid balance and blood pressure.5 The problem is that many people enjoy the taste of very salty foods and they include far too much sodium in their diets. Even when the cook has added salt to food in the kitchen, people will often add a lot more to their meal before eating it. The salt shaker is standard equipment at most American dinner tables. Restricting salt, so necessary for most people with kidney failure, can be one of the most difficult adjustments for some individuals. However, a high salt diet can result in devastating complications.
What problems are associated with too much sodium intake for people with CKD?
Having too much sodium in the body is closely linked with the retention of excess fluid. What happens when people eat salty food? They get thirsty, right? So they drink more fluid. When a person has kidney failure, the kidneys are unable to filter out the excess sodium and discard it from the body. Sodium absorbs fluid, so as one takes in more fluid, the sodium draws excess fluid into blood vessels, causing high blood pressure, and in body tissue, causing swelling (edema). Swelling, as mentioned previously, is usually first seen in the face, hands, legs and feet, but it can also build up around the lungs, heart and other vital organs. This can cause very serious health problems or even death. For a person on dialysis who gains more than the usual two-to-three kilograms (4-6 pounds) between treatments, longer dialysis treatments may be required. Because of the necessary removal of excess fluids, the patient may then experience cramping, dizziness and sometimes nausea and vomiting. Understanding the strong relationship between sodium and fluid should help people be more mindful of their salt and fluid intake!
What are some of the foods high in sodium (salt)?
Processed foods are often very salty and should be limited by those with CKD. It is important to check labels of processed foods for salt content. Some of the worst offenders include:
- Frozen, prepared meals
- Canned soups and entrees
- Snack foods/crackers/chips
- Cured meats such as ham
- Prepared seasonings
- Most restaurant foods
- bologna and hot dogs
- Iodized salt, lite salt and sea salt
What foods are low in sodium (salt?)
It is best to eat fresh vegetables and fruit, poultry, fresh-water fish and uncured meats. Most plain, frozen vegetables are also low in salt. Minimally processed foods such as breads, rolls and pasta are also on the list of low-salt foods. Renal dietitians are happy to provide their patients with a list of low-salt foods around which they can build their daily menus.
K Potassium (chemical symbol K) is a mineral found in many foods.
Normally functioning kidneys tightly regulate potassium levels in the body in order to maintain normal cell function, especially in the heart and muscles. For people on dialysis, potassium levels rise in between dialysis treatments. Therefore, foods with moderate to high amounts of potassium must be limited or eliminated from the diet.
What are some of the foods and beverages high in potassium?
- Brussel sprouts
- Carrot juice
- Collard Greens
- Dried Beans
- Dried fruits
- Grapefruit juice
- Lemonade, fresh
- Milk Products
- Milk, Soymilk
- Orange juice
- Potatoes (not soaked)
- Prune juice
- Salt substitute
- Tomato juice
- Winter squash
What are some of the foods and beverages low in potassium? (Some considered low when eaten in only ½-cup portions)
- Apple juice
- Bell peppers
- Bread products
- Cookies w/o choc
- Cranberry juice
- Fruit cocktail
- Grape juice
- Green beans
- Peach (1 or canned)
- Plum (1 or canned)
- Snow peas
- Soaked potatoes
- Unsalted crackers
- Unsalted pretzels
Ph Phosphorus (chemical symbol Ph) must also be monitored carefully for people with CKD. While found in every human cell, the primary function of phosphorus in the body is in the formation of bones and teeth. It also plays a role in the processing of carbohydrates and fats and in the production of protein, essential for the growth, maintenance and repair of cells and tissues. In combination with Vitamin B, phosphorus assists in muscle contraction, kidney function, heartbeat rhythm and nerve conduction.
People on dialysis often have to take a phosphate binder—medicine that attaches to the phosphorus which is in the food and allows for its excretion. The medicine is not a replacement of the need to limit high phosphorus foods. The renal dietitian can help people with CKD plan a diet which is lower in phosphorus.
What are some of the foods high in phosphorus?
- Bran & wheat cereals
- Cottage cheese
- Dried beans
- Garbanzo beans
- Organ meats
- Peanut butter
- Puddings made with milk
What are some of the foods and beverages low in phosphorus?
- All fruits
- All vegetables (except beans & peas)
- Cranberry juice
- Cream Cheese
- Fruit drinks
- Ginger ale
- Hard candy
- Lemon/lime sodas
- Nondairy creamer
- Root beer
- Salad dressing
- Sour cream
- Vegetable oils
Protein intake is essential for maintaining a person’s health. Protein helps to develop and heal body tissue, to build muscle tone, and to resist infection. It also helps to regulate certain enzymes and hormones.
Since people have such different health situations—many coping with more than one disease—there is no one-protein-level-fits-all plan. Each person should accept the advice of his/her physician and renal dietitian because they are familiar with an individual’s case.
What are some of the foods high in proteins?
Each person’s situation is different. When recommending a renal diet, dietitians takes into account individual needs, health status (including results of blood-lab tests), and personal tastes. They can provide prepared menus or help patients to plan meals tailored to their tastes while adhering to required dietary restrictions. This approach focuses on what foods a person can eat rather than emphasizing foods he/she cannot eat.
Sometimes people with CKD may throw up their hands and say “everything has something in it that’s bad for me. There is nothing I can eat.” Even though the diet is challenging, you have a renal dietitian available to suggest strategies to make it tolerable. You just need to ask for help!