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Preface and Contents

Diet in Chronic Kidney Disease

Salt intake

4. Salt (Sodium) Restriction in Diet
Why is a low sodium diet advised for patients with CKD?

Sodium in our diet is important for the body to maintain blood volume and to control blood pressure. Our kidneys play an important role in the regulation of sodium. In patients with CKD, the kidneys cannot remove excess sodium and fluid from the body so sodium and water build up in the body. An increased amount of sodium in the body leads to increased thirst, swelling, shortness of breath and increase in blood pressure. To prevent or reduce these problems, patients with CKD must restrict sodium intake in their diet.

What is the difference between sodium and salt?

The words sodium and salt are commonly used as synonyms. Common salt (table salt) is sodium chloride and contains 40% sodium. Salt is the principle source of sodium in our diet. But salt is not the only source of sodium. There are quite a few other sodium compounds in our food, such as:

  • Sodium alginate: Used in ice-cream and chocolate milk
  • Sodium bicarbonate: Used as baking powder and soda
  • Sodium benzoate: Used as a preservative in sauce
  • Sodium citrate: Used to enhance flavor of gelatin, desserts and beverages
  • Sodium nitrate: Used in preserving and coloring processed meat
  • Sodium saccharide: Used as artificial sweetener
  • Sodium sulfite: Used to prevent discoloration of dried fruits The above mentioned compounds contain sodium but are not salty in taste. Sodium is hidden in these compounds.

How much salt should one take?

A typical daily intake of salt is about 10 to 15 grams (4-6 grams of sodium) per day. Patients with CKD should take salt according to the recommendation of the doctor. CKD patients with edema (swelling) and high blood pressure are usually advised to take less than 2 grams of sodium per day.

Which foods contain high amounts of sodium?
Foods high in sodium include:

  1. Table salt (common salt), baking powder
  2. Processed foods like canned foods, fast foods and “deli” meats
  3. Readymade sauces
  4. Seasonings and condiments such as fish sauce and soy sauce
  5. Baked food items like biscuits, cakes, pizza and breads
  6. Wafers, chips, popcorn, salted groundnuts, salted dry fruits like cashew nuts and pistachios
  7. Commercial salted butter and cheese
  8. Instant foods like noodles, spaghetti, macaroni, and cornflakes
  9. Vegetables like cabbage, cauliflower, spinach, radish, beetroot, and coriander leaves
  10. Coconut water
  11. Drugs like sodium bicarbonate tablets, antacids, laxatives
  12. Non-vegetarian foods like meat, chicken, and animal innards like kidneys, liver and brain
  13. Seafoods like crab, lobster, oyster , shrimp, oily fish and dried fish

Practical Tips to Reduce Sodium in Food:

  1. Restrict salt intake and avoid extra salt and baking soda in diet. Cook food without salt and add permitted amounts of salt separately. This is the best option to reduce salt intake and ensure consumption of the prescribed amount of salt in everyday diet.
  2. Avoid foods with high sodium content (as listed above).
  3. Do not serve salt and salty seasonings at the table or altogether remove the salt shaker from the dining table.
  4. Carefully read labels of commercially available packaged and processed foods. Look not only for salt but also for other sodium containing compounds. Carefully check the labels and choose “sodium-free” or “low-sodium” food products. Make sure however that potassium is not used to substitute sodium in these foods.
  5. Check sodium content of medications.
  6. Boil vegetables with high sodium content. Throw away the water. This can reduce sodium content in vegetables.
  7. To make a low salt diet tasty, one can add other spices and condiments such as garlic, onion, lemon juice, bay leaf, tamarind pulp, vinegar, cinnamon, cloves, nutmeg, black pepper, and cumin.
  8. Caution! Avoid the use of salt substitutes as they contain high amounts of potassium. High potassium content of salt substitutes can raise the potassium levels in blood to dangerous levels in CKD patients.
  9. Do not drink softened water. In the process of water softening, calcium is replaced by sodium. Water purified by reverse osmosis process is low in all minerals including sodium.
  10. While eating at restaurants, select foods that contain less sodium.