From the Guidelines
No, there are no studies showing that more sodium intake is better for chronic kidney disease (CKD) patients. In fact, the opposite is true - most medical evidence supports sodium restriction for CKD patients. The general recommendation is to limit sodium intake to less than 2 g of sodium per day (or <90 mmol of sodium per day, or <5 g of sodium chloride per day) in patients with high BP and CKD, as suggested by the 2021 KDIGO clinical practice guideline for the management of blood pressure in CKD 1.
Key Points to Consider
- Excessive sodium intake leads to increased blood pressure, greater fluid retention, and can worsen proteinuria (protein in urine), all of which accelerate kidney damage.
- Sodium restriction helps control blood pressure, reduces fluid overload, decreases proteinuria, and may enhance the effectiveness of blood pressure medications like ACE inhibitors and ARBs.
- CKD patients should focus on eating fresh, unprocessed foods, reading nutrition labels carefully, using herbs and spices instead of salt for flavoring, and consulting with a renal dietitian for personalized guidance on sodium intake appropriate for their specific stage of kidney disease.
- The recommendation to limit sodium intake is consistent with other guidelines, including the KDIGO 2020 Guideline for the Management of Patients with Diabetes and CKD 1, and is supported by evidence from studies in the general population and in patients with CKD 1.
Lifestyle Interventions
- In addition to sodium restriction, CKD patients should be advised to undertake moderate-intensity physical activity for a cumulative duration of at least 150 minutes per week, or to a level compatible with their cardiovascular and physical tolerance 1.
- A balanced, healthy diet that is high in vegetables, fruits, whole grains, fiber, legumes, plant-based proteins, unsaturated fats, and nuts, and is lower in processed meats, refined carbohydrates, and sweetened beverages, is recommended for CKD patients 1.
From the Research
Sodium Intake in CKD Patients
- There is no evidence to suggest that higher sodium intake is beneficial for CKD patients 2, 3, 4, 5.
- In fact, studies have consistently shown that high dietary sodium intake is associated with increased risk of cardiovascular disease and CKD progression in CKD patients 2, 3, 4, 5.
- Reducing sodium intake to the target of 50-85 mmol/24 h in patients with CKD has been shown to reduce blood pressure and proteinuria, and should be actively pursued to improve outcome in CKD 3, 4, 5.
Benefits of Sodium Restriction
- Sodium restriction has been shown to have a protective effect on CKD patients, particularly when combined with renin-angiotensin-aldosterone system (RAAS) blockade 3, 4, 5.
- Moderate sodium restriction can substantially improve the protective effects of RAAS-blockade in CKD, by specific renal effects apparent from proteinuria reduction 4.
- Sustainable sodium restriction can be achieved through approaches based on behavioral sciences, and prospective studies should assess the efficacy and sustainability of different strategies to target high sodium intake in CKD 4, 5.
Potential Risks of Low Sodium Intake
- While there are concerns regarding the adverse effects of very low sodium intake, moderate sodium restriction is generally considered safe and effective for CKD patients 4, 5.
- The implementation of a low-sodium diet should be personalized, taking into account the volume status and true burden of hypertension evaluated by ambulatory BP monitoring 5.