The kidneys are primarily responsible for filtering waste products from the blood and dispelling them out of the body through urine. When the kidneys are unable to function properly, it can result in waste building up in the body and preventing organs from being able to work effectively. Complications of kidney damage or failure may include swelling of the arms and legs, heart disease, weakened bones, or damage to the immune system or central nervous system. As part of their treatment plan, people with kidney damage will usually be advised to follow a renal diet, an eating plan that is designed to ensure the least amount of waste products enter the body through food as possible.
The exact version of the eating plan will typically vary between each individual due to the severity of his or her condition and what other treatment options he or she is on. One of the most common renal diet foods for the majority of people with kidney issues tends to be items that are low in water content and potassium levels. Damaged kidneys are not as easily able to filter out excess liquid from the body, so eating foods with high water content may make a person more likely to retain liquid and suffer from swollen arms and legs. Potassium, a mineral that aids the functioning of the heart, can also build up to dangerous levels since the kidneys may be not filter enough potassium out of the body; therefore, high-potassium foods are usually advised to be avoided on a renal diet plan.
Renal diet foods that tend to be recommended most often are fruits and vegetables that are lower in water content and potassium levels. Fruits that are usually approved on a renal diet include apples, pears, berries, and peaches, while bananas and oranges, which tend to have high amounts of potassium, can potentially cause complications and are often limited. Vegetables that fit the criteria on the renal diet include carrots, broccoli, cauliflower, celery, and peppers, while starchy vegetables like pumpkins, potatoes, and winter squash are generally avoided due to their fluid content or potassium levels.
In addition to fruits and vegetables, whole grains are also another of the most common renal diet foods included in the majority of recommended eating plans, regardless of the type of treatment option a patient is receiving. Once the treatment options are taken into account, certain renal diet foods may be altered. Dialysis is a treatment for kidney failure that uses specialized machines to mimic the functionality of the kidneys and filter out waste from the blood. People whose kidney conditions are not yet severe will generally not be on dialysis and their renal diet will usually limit sources of protein, such as eggs, chicken, fish, or beans, because protein tends to leave behind higher amounts of waste products in the blood than carbohydrates. A person on dialysis will generally require a high amount of protein in his or her diet because the dialysis process may filter out too much of the protein that is needed to maintain the body.
What Is a Renal Diet?
When you are experiencing kidney problems, your doctor may prescribe a renal diet. Acute kidney injury (AKI) and chronic kidney disease (CKD) are life-threatening conditions. If you have renal problems, you can manage your symptoms with diet. Metabolic processes influence kidney function. An accumulation of some substances can result in blood toxicity. Potassium, sodium, and other substances can build up concentrations in the bloodstream that can cause problems with homeostatic balance. Eating healthy foods and avoiding others is the first step in managing kidney disease.
Oxidation
Oxidation happens when systems in the body have reactions to sources of high fats. Oxidative stress increases the incidence of renal injury. Kidney disease is susceptible to the levels of several metabolic end products. Nitrogen, creatinine, or uric acid can accumulate to toxic levels when kidney functionality is impaired. This harmful build-up of free radicals may lead to an abrupt loss of renal function and other serious diseases such as inflammation, diabetes, cancer, and DNA damage.
Antioxidants
Your body has antioxidant defenses to reverse oxidative stress. Antioxidant-rich foods and supplements work to maintain health and reverse kidney imbalances. There are a variety of dietary and supplemental sources of antioxidants.
- Fruits and vegetables
- Seeds, nuts, and grains
- Coffee, tea, and cocoa
- Flavonoids, carotenoids, and tannins
- Vitamin C and E
Renal Diet
A renal dietician or doctor is the best resource for adopting a personalized renal diet. There are several foods that are commonly recommended by medical research to improve kidney functions.
Vegetables
Leafy greens are especially beneficial in body detoxification. They are an excellent source of fiber and minerals.
- Cabbage is high in vitamins K, C, and B6, folic acid, and a host of phytochemicals that reverse the damage of free radicals.
- Cauliflower, another cruciferous vegetable, is loaded with folate, fiber, indoles, glucosinates, and thiocyanates and helps neutralize toxic substances.
- Garlic and onions, both alliums, lower cholesterol, reduce inflammation and are rich in flavonoids like quercetin, a powerful antioxidant.
Fruits
Fruits have many phytonutrients that are excellent free-radical scavengers. Berries are among the healthiest foods you can eat. They are all high in fiber, vitamin C, and antioxidants.
- Cranberries are especially effective at cleaning bad bacteria out of the urinary tract, protecting the gastrointestinal tract, and have even been shown to prevent cancer and heart disease.
- Apples can reduce cholesterol, aid in digestion, and are high in anti-inflammatory compounds.
- Blueberries have anthocyanidins, vitamin C, and manganese for healthy bones, and can protect the brain from the effects of aging.
- Raspberries contain folate, vitamin B, ellagic acid, and anthocyanins and can even inhibit cancer and tumor formation.
Renal Nutrition Goals
In addition to adding beneficial foods, you should consider several factors in your diet. Eating healthy poly- and monounsaturated fats, limiting cholesterol and protein, and watching for signs of fluid retention are important elements of a healthy kidney diet.
How Much Phosphorus Is Allowed on a Renal Diet?
The amount of phosphorous in your diet is important to manage for people with chronic kidney disease. Nutritionists recommend that healthy adults have less than 4,000mg of phosphorous each day, and under 3,000mg if over 70 years old. If CKD progresses to stage 3, then the recommended amount is no more than 700mg to 1,200mg each day.
Foods High in Phosphorous
The foods with the most phosphorous are also high in protein. Meat, dairy products, meat alternatives, and some whole grains have the highest concentrations of phosphorous.
- Proteins such as chicken and turkey, pork, and especially organ meats have high amounts. A single recommended serving can have up to 50% of your daily intake.
- Dairy products make up 20-30% of recommended daily value of phosphorous in American diets. A single ounce of hard cheese can have a third of your daily serving.
- Other sources like sunflower and pumpkin seeds, nuts. and whole grains are also rich in phosphorous and should be eaten in moderation.
How Much Sodium Is Allowed on a Renal Diet?
When some salts build up in your blood, it can take a toll on your kidneys. Sodium levels need to be monitored for patients with kidney problems. One teaspoon of table salt averages 2,300 mg. A kidney-friendly diet typically limits sodium to about 2,000mg per day. If in stage 3 CKD, then studies recommend as little as 1,000mg a day.
Foods High in Sodium
Sodium is a necessary neurotransmitter but must be eaten with care on a renal diet. Sodium-rich foods are also typically highly processed. Deli meat, soups, fast food, and, of course, salty snacks, are all to be avoided when healing kidney disease.
