Renal Diet Guide

Beginners Guide to a Renal Diet

The kidneys are vital organs that play a major role in the removal of waste products and excess fluids from the body. Unfortunately, due to certain medical conditions, the kidneys may not function properly. As a result, the body may accumulate wastes and an excess of fluid. Waste accumulation is potentially fatal to the human body. Hence, it is essential to keep one’s kidneys healthy. One effective way to do so is to follow a renal diet (also referred to as a CKD diet or kidney-friendly diet.

PLEASE NOTE: Everyone's renal diet is different. You should consult a kidney dietician and learn what your specific diet should look like.

What Is a Renal Diet?

A renal diet is one that is designed for patients suffering from kidney diseases such as chronic renal failure, Nephrotic Syndrome, Diabetic Nephropathy, among others. Today, doctors and other healthcare professionals refer almost all newly diagnosed kidney patients to a dietician to receive counseling on the renal diet. The ideal CKD diet should be low in sodium, low in potassium, and low in phosphorus.

Benefits of the Renal Diet

The renal diet is not based on mere claims and assumptions. In fact, the renal diet is a science-backed diet that has been developed after numerous studies. Studies show that following a kidney-friendly diet can protect the kidneys from further damage and may also prolong survival.

But how exactly does a renal diet work? Well, a renal diet works by decreasing the number of waste products inside the body. As a result, this reduces the workload exerted on the kidneys and optimizes their function while preventing further damage.

What to Eat on a Renal Diet

While each patient is unique and requires diet planning specific to their individual needs (age, activity level, comorbidities, etc.), there are guidelines that apply to a general kidney diet. The kidney diet is designed to control the intake of:

  • Sodium
  • Potassium
  • Phosphorus
  • Protein
  • Fluids

Lower Sodium Intake

Sodium, commonly found in salt, is a mineral used by the body to maintain fluid balance. A diet high in sodium is inappropriate for a patient suffering from renal problems since damaged kidneys cannot remove excess sodium from the body. As a result, renal patients who consume a lot of sodium tend to become easily dehydrated and may develop a condition known as hypernatremia. Sodium excess leads to swelling, high blood pressure, and at worst heart failure.

The recommended sodium intake for a patient with chronic kidney disease is less than 2,000 mg or 90mmol per day.

Eat Less Potassium

Potassium is an essential mineral used by the body for muscular contractions, nerve signaling, and fluid balance. Normally, the kidneys are responsible for the filtration of any excess in potassium through urine. Damaged kidneys, however, cannot filter an adequate amount of potassium from the body. Consequently, this may lead to a state of high potassium level which is commonly known as hyperkalemia. Hyperkalemia is a very dangerous state of mineral imbalance. It can cause muscle weakness, weaker or irregular heartbeats, and in severe cases may even lead to death.

The recommended intake of potassium is less than 2,000mg per day. Patients should switch high potassium food options to low potassium ones. Kidney patients are also advised to read labels on packaged foods and to avoid foods that contain potassium chloride.

Eat Less of Phosphorus-rich Foods

Phosphorus is another mineral used by the body in bone and teeth formation. Patients with kidney problems cannot filter out phosphorus from the blood. Consequently, this usually leads to a state of high phosphorus level, which doctors refer to as hyperphosphatemia. Hyperphosphatemia can cause muscle cramps, tingling around the mouth, joint pain, among other symptoms. At worst, high levels of phosphorus in the blood can cause dangerous calcium deposits in the lungs, blood vessels, and eyes.

To maintain a safe level of phosphorus within the blood, studies recommend that kidney patients should restrict their intake to less than 800 mg a day.

Decrease Protein Consumption

Kidney patients should avoid a high protein diet. Research shows that high protein intake increases the pressure inside the kidneys, hence causing more damage. This is because the kidneys are made up of very tiny clusters of capillaries known as glomeruli. Glomeruli are very fragile structures that cannot sustain high pressures.

Additionally, proteins are broken down by the body into urea. Normally, urea is excreted by the kidneys as urine. However, when the kidneys do not function properly, this can result in a build-up of urea. Excess urea, also known as uremia can be fatal. Uremia can lead to seizures, loss of consciousness, and heart attacks.

Experts recommend eating a low-protein diet of 0.6 -0.8 g/kg/day so as to reduce the workload on the kidneys and to lower the risk of uremia. However, patients on dialysis are recommended to increase their protein intake as dialysis already caters for the removal of proteins and its waste products from the bloodstream.

Another very important point to be noted is that renal patients should not eat two different proteins at the same time. Eating a bowl of pulses with chicken as a side is not recommended. Renal patients should choose either or but not both.

Avoid Fluid Excess

The human body needs water to survive. However, renal patients need fewer fluids. This is because, in renal patients, the kidneys cannot remove excess fluids from the body in the form of urine. Hence, if renal patients were to drink the same amount of water as individuals with properly functioning kidneys, they would accumulate a lot of fluid inside their bodies. Fluid overload can lead to serious conditions such as high blood pressure and at worst, heart failure. Experts advise drinking from small cups and quenching thirst by rinsing the mouth when the irresistible sensation starts to kick in.

Opt for Nutritious, Kidney-friendly Fruits & Vegetables

Studies show that opting for a plant-based renal diet can help protect the kidneys from further damage. This section brings forward a list of kidney-friendly foods that are low in sodium, potassium, and phosphorus.

Here are the recommended kidney-loving options:

  • Radish
  • Arugula
  • Onions
  • Cabbage
  • Cauliflower
  • Bell Peppers
  • Red Grapes
  • Blueberries

Choose Healthy and Kidney-friendly Snacks

Since the kidneys are also responsible for the regulation of blood pressure, kidney problems may also lead to high blood pressure problems. High blood pressure can, in turn, lead to more kidney damage as the structures that make up the kidneys cannot sustain very high pressures. This sets up a vicious circle of high blood pressure and kidney damage.

Health experts recommend cutting down on salty snacks as too much salt may further shoot the blood pressure levels. Instead, experts recommend opting for healthy, kidney-friendly snacks such as unsalted macadamia nuts. Macadamia nuts are low in phosphorus as compared to other nuts.

Foods to Avoid on a Renal Diet

There are thousands of food options that are particularly bad for the kidneys. Doctors and dietitians recommend watching out for these kidney-enemies:

  • Whole wheat bread
  • Brown rice
  • Canned foods
  • Highly processed meats
  • Instant meals packed with lots of preservatives
  • Dark soda
  • Potassium-rich fruits such as avocados, bananas, oranges, apricots, tomatoes, dried dates, raisins, and prunes.
  • Potassium-rich vegetables such as spinach and Swiss chard.


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