Sodium and Your CKD Diet: What You Need to Know

1. The Link Between Sodium and Chronic Kidney Disease

Table salt, used daily, combines minerals such as sodium and chloride (NaCl). The human body requires both but in an adequate amount. Excessive sodium consumption strains the kidneys, and CKD patients should be strict about their sodium intake.

Role of Salt in the Body

Sodium is an essential mineral, and the body requires it to survive. It is helpful for the normal functioning of nerves and muscles. Sodium is also necessary to control fluid and maintain blood pressure levels. The sodium amount should be consumed in a balanced amount because excess sodium is dangerous for health and causes complications.

The kidneys regulate sodium balance by filtering and reabsorbing sodium, depending on the body's requirements. However, in patients with CKD, the kidneys lose their ability to regulate sodium balance, which makes it harder to maintain the necessary sodium balance.

High levels of sodium harm chronic kidney disease (CKD) patients, causing increased blood pressure, proteinuria (protein leakage), inflammation, and excessive fluid build-up that results in swelling.

The American Kidney Fund reported that individuals with CKD who consumed high amounts of sodium experienced faster kidney function decline compared to those with a lower sodium intake. Similarly, the National Kidney Foundation highlighted the importance of reducing sodium intake to help preserve kidney health and prevent complications such as hypertension, fluid retention, and heart disease.

2. How Sodium Affects Kidney Function

The kidneys are responsible for maintaining the body’s internal environment and normal values of sodium in the body. When sodium exceeds, the kidneys filter excess sodium from the blood and maintain appropriate levels for proper cellular functions.  High sodium intake increases the fluid volume in the bloodstream, which raises blood pressure. When the kidneys become damaged, especially in CKD, the high levels of sodium put strain on the kidneys and further worsen the disease. The damage to the blood vessels contributes to the progression of CKD and may eventually lead to kidney failure. As a result, sodium accumulation in the body causes fluid retention and swelling, especially in the legs, ankles, and face.

The National Kidney Foundation concluded their studies highlighting the connection between high sodium intake, hypertension, and kidney disease. According to NKF, limiting sodium consumption improves heart and kidney health.

3. Why Sodium Restriction is Essential for CKD Patients

For CKD patients, excessive sodium intake worsens the symptoms and leads to increased fluid retention and blood pressure. When kidneys lose their ability to regulate sodium levels properly, sodium accumulates, causing the body to retain water. The fluid retention leads to swelling (oedema) and makes it difficult for the heart and kidneys to function efficiently. By limiting sodium, CKD patients can reduce these issues and better manage their symptoms.

Sodium Requirements for CKD patients

According to NIH, the recommended daily sodium intake for healthy adults is less than 2,300 milligrams (mg) daily, equivalent to about one teaspoon of table salt. For CKD patients, the recommended amount is to restrict their sodium intake to 1,500 - 2,000 milligrams (mg) per day. 

How Does Sodium Restriction Reduce the Need for Dialysis?

Sodium restriction reduces the need for dialysis in the following ways:

• Controlling blood pressure: Blood pressure can be controlled by lowering sodium intake, which slows the progression of kidney disease.

• Lowers fluid retention: Sodium restriction can minimise fluid retention. Moreover, it also reduces the burden on the heart and kidneys, delaying the need for dialysis.

• Preserve kidney function: By lowering sodium intake, the kidneys can function more efficiently. Limiting sodium can also prevent further damage and reduce CKD complications.

• Prevention of proteinuria:  Limiting sodium also reduces proteinuria (protein in the urine), protecting the kidneys from long-term damage and reducing the need for dialysis.

• Improved response to medicines: A diet low in sodium enhances the effectiveness of drugs that control blood pressure and reduce proteinuria, such as ACE inhibitors or ARBs. It also contributes to better kidney health and delays the need for dialysis.

• Reduces the risk of cardiovascular diseases: With lower sodium intake, patients can reduce their risk of heart-related complications that are closely linked to kidney health.

The National Kidney Foundation (NKF) and the Kidney Disease Outcomes Quality Initiative (KDOQI) concluded in their studies that a low-sodium diet slows the progression of CKD.

Impact of High Blood Pressure on the Heart:

The blood pressure increases when fluid and sodium accumulate in the blood and tissues. Hypertension caused by excessive intake of sodium worsens the health of the heart and kidneys in CKD patients. The heart is badly affected by excess salt in the body. If the patient has high blood pressure and consumes excess sodium in their diet, it increases the pressure on the heart which makes it weaker and enlarged.

Similarly, CKD patients are at higher risk of heart failure due to the combined effects of hypertension and fluid overload caused by high sodium intake. Sodium restriction manages blood pressure, reduces the workload on the heart, and lowers the risk of heart failure, which is a leading cause of morbidity and mortality in CKD patients.

Reducing sodium intake is one way to protect heart health with kidney disease. People can also consult with healthcare or dietitians to adjust their recommended daily sodium intake according to their disease condition.

4. Low-Sodium Foods to Include in a CKD Diet

Low-sodium foods are beneficial for CKD patients to control and manage symptoms in CKD patients such as thirst and extra fluid, regulate blood pressure, and improve discomfort during dialysis. 

Foods that are naturally low in sodium and allowed for the early stages of CKD patients are 

• Fresh or frozen fruits
• Fresh or frozen vegetables without sauce
• Whole grain rice or pasta
• Canned beans, rinsed or with no sodium added
• Beef, chicken, and turkey with no added seasonings or brines
• Fresh or frozen fish
• Eggs

The table below also highlights kidney-friendly foods with serving sizes that are lower in sodium and beneficial for CKD patients with their sodium content.

Category	Food Type	Examples	Serving Size	Sodium Content (mg)
Vegetables	Fresh, Leafy Vegetables	Spinach, Kale, Lettuce, Cucumbers	1 cup (raw)	15-30 mg
	Root Vegetables (Low-Potassium)	Carrots, Radishes, Zucchini	1 cup (raw)	30-40 mg
	Cruciferous Vegetables	Cauliflower, Broccoli, Cabbage	1 cup (cooked)	20-40 mg
Fruits	Low-Sodium Fruits	Apples, Blueberries, Strawberries	1 medium apple / 1 cup berries	0-5 mg
	Citrus (Low Potassium)	Lemons, Limes	1 fruit	0-2 mg
	Moderate Potassium Fruits	Watermelon, Pineapple, Grapes	1 cup	0-5 mg

 

When following a low-sodium diet for CKD, portion control is important to manage complications. Even healthy foods can contribute to sodium or potassium buildup if consumed in excess. Therefore, it is important to consume food taken in

• Measured portion sizes.
• Combine different food groups to ensure a balanced intake of nutrients.
• Avoid adding salt or high-sodium seasonings to meals; use flavor with herbs and spices.

5. Identifying and Avoiding Hidden Sodium in Processed Foods

Some processed foods like canned soups, fast food, and sauces also contain higher amounts of hidden sodium.

• Canned Soups: A convenient and nutritious meal, but many canned soups contain a hidden sodium content of 700 mg per serving.
• Fast Food: Most consumed foods such as burgers, fries, and chicken nuggets often contain high sodium content, which exceeds the daily recommended limit in a single meal.
• Sauces: Some common sauces used on a daily basis, such as soy sauce, ketchup, and marinades, are higher in sodium and should be restricted for CKD patients.

Other daily foods contain hidden sodium, such as instant noodles, deli meats, enriched white bread, cereals, Thai chili sauce, and pickled vegetables.

 

While consuming processed foods, it is essential to identify and avoid hidden sodium from the food, especially in CKD. Processed foods usually contain high levels of sodium, which causes health problems like high blood pressure and cardiovascular disease. 

Hidden sodium in processed foods is risky, as many foods that don’t taste salty still contain high amounts. Always read the Nutrition Facts label to compare foods. Choose foods with the lowest Percent Daily Value (%DV) for sodium. The %DV represents whether a food is high or low in sodium. 5% or less is low, and 20% or more is high.

Therefore, it is essential to understand the hidden amount of sodium in the packed items from the ingredient list and to make informed choices for better health. The sodium amount is mentioned in processed foods in the following ways.

• Sodium Free - Only a minimal amount of sodium per serving.
• Very Low Sodium - 35 mg or less per serving.
• Low Sodium - 140 mg or less per serving.
• Reduced Sodium - The level of sodium is reduced by 25% in some foods
• Light or Lite in Sodium - Foods in which the sodium is reduced by at least 50%.

So, the simple rule of thumb is to remember salt intake before consuming processed foods. If the salt is listed in the first five ingredients, the item has excess sodium to consume.

How to Use Sodium-Free or Reduced-Sodium Substitutes?

Here are some simple ways for CKD and hypertensive patients to reduce their sodium intake from the meal.

• Eat only small amounts of high-salt foods.
• Consume fresh foods like fruit, vegetables, legumes, whole grain bread, and rice.
• Use more herbs and spices.
• Read food labels before consuming processed foods for sodium and use food labels to choose the lowest salt products.
• Consume lower sodium foods and their alternatives 

 

These are some substitutes for higher sodium foods that are safe to consume for CKD patients.

High Sodium Food	Alternative Food Items for High-Sodium Foods
Canned Soup	Homemade Soup
Frozen Pizza	Homemade Pizza (made without salt)
Packaged Deli Meats (Ham, Salami)	Fresh Meat (No Added Salt)
Chips (Potato Chips)	Fresh Homemade Chips (without salt)
Instant Noodles	Homemade Noodles (without added salt and spices)
Canned Vegetables	Fresh Vegetables
Cheese (Processed)	Fresh Cheese (Mozzarella)
Canned Beans	Fresh Beans
Pre-packaged Salad Dressings	Homemade Salad Dressings
Condiments (Ketchup, Soy Sauce)	Homemade Condiments

 

6. How to Season Your CKD-Friendly Meals Without Salt

Here is the list of salt-free herbs and spices that are lower in sodium and can be used to flavour meals. It includes

• Garlic
• Basil
• Thyme
• Rosemary
• Apple pie spice
• Cardamom
• Bay Leaf
• Flat-leaf parsley 

People with CKD can also blend these spices to store in a jar for a long time. These blends of spices can be used to spice up dishes without using salt in their diet. 

Fish and Poultry	For Multipurpose Mixture	Hot and Spicy	Smoky Blend
5 tsp onion powder 1 tbsp garlic powder 1 tbsp paprika 1 tbsp ground mustard 1 tsp dried thyme 1/2 tsp pepper 1/2 tsp celery seed	1 tbsp garlic powder 1 1/2 tsp dried basil 1 1/2 tsp dried parsley 1 1/4 tsp dried savory 1 1/4 tsp dried thyme 1 tsp dried mace 1 tsp onion powder 1 tsp ground black pepper 1 tsp dried or ground sage 1/4 tsp cayenne pepper	1tbsp chilli powder 2 tsp garlic powder 2 tsp onion powder 1 ½ tsp ground cumin 1 tsp dried Mexican oregano 1 tsp smoked paprika ½ tsp cayenne pepper ½ tsp black pepper	1 tbsp smoked paprika 1 tbsp paprika 1 tbsp garlic powder 1 tbsp black pepper 1 tbsp ground cumin 1 1 tbsp turmeric 1 tbsp onion powder

Role of Salt Substitutes for CKD Patients:

Salt substitutes, such as potassium-based salts, have a taste similar to salt. It benefits those with lower potassium levels in CKD, decreases blood pressure, and enhances food flavor. Nutritionists and dietitians often recommend salt substitutes to reduce sodium intake with different herbs, spices, and seasonings. These salt substitutes also reduce cravings for salty flavours.

Some salt substitutes, such as potassium chloride, contain potassium and may not be safe for CKD patients. Patients with potassium-restricted diets should be cautious while consuming salt substitutes. Depending on their health conditions, patients should always consult a healthcare provider or dietitian before consuming any salt substitute. 

Salt-Free Cooking Method

The cooking method greatly influences the flavour of a meal without adding salt. For CKD patients, the following techniques should be considered while cooking to enhance the flavour of the meal while retaining the taste.

• Grilling: Besides being smoky, the method caramelizes meats and vegetables' flavour, making them more savoury.
• Steaming: This method retains the natural flavours of vegetables and proteins without salt.
• Slow Cooking: Allows herbs and spices to merge deeply into dishes and enhances flavour over time.
• Roasting: Brings natural sweetness in vegetables and proteins and provides a rich taste.

 

These are some salt-substitute recipes.

 

• Spanish-style lentils with eggs

Ingredients:

• 2 tbsp fresh parsley, chopped
• 1 large beef tomato or 2 medium tomatoes
• 2 medium eggs
• 2 tsp olive oil
• 1 small onion, peeled and finely chopped
• 1 clove garlic, peeled and crushed
• ½ red pepper, deseeded and diced
• ½ green pepper, deseeded and diced
• ½ low-salt vegetable stock cube
• 1 tsp smoked paprika
• 410g (14oz) can green lentils, drained

Nutritional Information:

Each portion contains

• Energy: 392 kcal (1645 kJ), 20%
• Carbohydrate: 40.8 g
• Fibre: 14 g, 47%
• Sugars: 8 g (Low), 9%
• Fats: 10.2 g (Low), 15%
• Saturates: 2.2 g (Low), 11%
• Salt: 0.26 g (Low), 4%

Recipe:

• Add the onion, garlic, and chopped pepper to a non-stick frying pan with heated olive oil. Fry until tender for approximately 10 minutes.
• Stir in the drained lentils and crumble in the paprika and ½ stock cube. Cook for an additional two minutes after adding half of the parsley.
• Cut the tomato into cubes that are 1 cm or ½ inch. Add in the mixture of lentils. Crack an egg into the mixture.
• Cover the pan and cook for a few minutes until the egg has cooked to your liking.
• To serve, scatter the remaining parsley on top.
• Spiced turkey and black bean salsa

Ingredients:

• 1 handful of fresh coriander
• 1 tbsp vegetable or sunflower oil
• 300g (11oz) diced turkey
• Black pepper
• 1 tin black beans, drained (240g/8oz drained weight)
• 150g (5oz) tinned sweetcorn, drained (a 200g tin of sweetcorn soaked in water or use 150g of frozen sweetcorn)
• 1 lime
• 40g (2oz) rocket
• 1 tbsp Mexican spice mix (1 tsp dried oregano, 1 tsp ground cumin, 1 tsp ground coriander and 1 tsp smoked paprika)

Nutritional Information:

Each portion contains

• Energy: 638kcal (2669 kj), 32%
• Carbohydrate: 50.9g
• Fibre: 21.1g (70%), 70%
• Sugars: 11g (Low), 33%
• Fats: 23.4g (High)
• Saturates: 4.7 g (Low), 24%
• Salt: 0.23 g (Low), 4%

Recipe:

• Cut the half-baby plum tomatoes.
• Dice the roasted red pepper into pieces. After peeling and destoning the avocado, slice it thinly. Chop the coriander roughly.
• Put half a tablespoon of oil in a medium-sized pan and heat it over medium heat. After adding the diced turkey, cook for five minutes, rotating occasionally. Season with black pepper after adding the Mexican spice blend and stirring to mix. The turkey should be cooked through after another two to three minutes of pan-frying.
• Drain and rinse the black beans while the turkey cooks. Empty the sweetcorn. Add the black beans, sweetcorn, baby plum tomatoes, red pepper, and coriander to a medium-sized frying pan heated to medium heat with 1/2 tablespoon of oil. Cook until the beans are thoroughly cooked, about 5 minutes. Squeeze the lime juice on top. Add black pepper for seasoning.
• Arrange the rocket leaves on plates to serve. Add chunks of avocado, seasoned turkey, and warm black bean salsa.

7. Meal Planning Tips for CKD Patients

Managing the complications of CKD is difficult, but it can be managed through proper meal planning and a balanced diet. These are some tips for the patient to manage their CKD conditions.

Manage Portion Size and Follow Meal Planning Tips:

Managing portion sizes and reducing sodium intake are important in the CKD diet. High sodium can increase blood pressure and lead to fluid retention, worsening kidney function.

• Use measuring cups or a food scale to ensure you eat the correct portions.
• Fill half your plate with non-starchy vegetables, lean protein (skinless poultry or fish), and whole grains or starches (brown rice or sweet potatoes).
• Serve smaller portions of high-potassium foods, like bananas or tomatoes, if your potassium levels need to be monitored.
• Choose fresh and unprocessed foods because they naturally contain less sodium.
• Avoid canned or packaged foods unless labeled low sodium or no added salt.
• Use herbs, lemon juice, or salt-free seasoning to flavour meals instead of table salt.
• Batch cooking is an excellent strategy to ensure you always have CKD-friendly meals.
• Choose moderate amounts of high-quality protein from skinless chicken, fish, or eggs. Limit red meat and processed meats high in sodium.
• If potassium and phosphorus levels are already high, avoid high-potassium foods like bananas, oranges, tomatoes, and potatoes. Use substitutes such as apples, grapes, and berries

8. Monitoring Sodium Intake: Tools and Strategies

CKD patients should routinely measure and monitor their sodium levels with the help of their healthcare team. Doctors and dietitians can guide patients on setting appropriate sodium limits based on the stage of CKD and other health factors like hypertension.

Some online applications, such as Sodium Tracker (CDC) and MyFitnessPal, are also available to track sodium intake. It is also recommended to consult a dietitian or nutritionist to limit your sodium intake with customised meal plans.

Patients can also prepare and portion out low-sodium meals for the week to avoid processed or high-sodium foods. Regularly checking food labels for sodium content becomes a habit. Patients should also learn to prevent high-sodium snacks, canned foods, and condiments. When eating out, patients request meals with no added salt and ask for sauces or dressings on the side to control sodium intake.

The World Health Organization (WHO) reported that an estimated 1.89 million deaths each year are associated with excessive sodium consumption, which is linked with increased blood pressure and an increased risk of cardiovascular disease.

Frequently Asked Questions:

How much sodium is safe for CKD patients?

CKD patients should limit sodium intake to less than 2000 mg per day to help manage blood pressure and prevent fluid retention.

Can I use salt substitutes if I have CKD?

Some salt substitutes contain potassium, which can be harmful to CKD patients. Always consult your doctor before using any substitutes.

How do I reduce sodium in restaurant meals?

Choose meals without added salt, choose grilled or baked options, avoid sauces or dressings, and ask the management for nutrition information.

What are some low-sodium snacks for CKD patients?

Low-sodium snack options include unsalted nuts, fresh fruits, raw vegetables, plain rice cakes, and low-sodium popcorn.

Why is reducing sodium important for CKD patients?

Reducing sodium helps control blood pressure, reduces fluid buildup, and decreases the risk of heart disease, which are crucial for CKD management.

Can I eat canned or processed foods with CKD?

Canned and processed foods are often high in sodium. If you consume them, look for low-sodium or no-salt-added options, and rinse canned items like vegetables to reduce sodium content.