Recently, at the Annual Meeting of the Chinese Diabetes Society (CDS), Professor Zhu Zhiming from the Department of Hypertension and Endocrinology, Daping Hospital, Army Medical University, delivered a systematic and in-depth presentation on the practical dilemmas and strategic choices of clinical salt control in diabetic patients.
Current international guidelines have provided recommendations for sodium intake in patients with diabetes. The American Diabetes Association (ADA) suggests that diabetic patients should limit their daily sodium intake to 1500–2300 mg, equivalent to 3.8–6.0 g of sodium chloride per day. The Chinese Guidelines for the Prevention and Treatment of Diabetes (2024 Edition) recommends that diabetic patients restrict salt intake to less than 5 g per day, and those with hypertension may further reduce their intake. Meanwhile, high-salt foods should be limited, such as monosodium glutamate, soy sauce, salted processed foods, and sauces.
In real-world practice, adherence to salt restriction measures is generally poor. Relying solely on health education can hardly change dietary habits in the long term. Although salt substitutes can theoretically reduce sodium load, they have taste problems, and high-potassium salts are contraindicated in patients with chronic kidney disease. A gradual salt-reduction strategy is considered more consistent with behavioral principles, but clear evidence supporting its long-term efficacy is still lacking. Epidemiological surveys show no significant change in global salt intake over the past 20 years.
In patients with diabetes and hypertension, salt-restriction interventions do exert a clear blood pressure-lowering effect. Multiple randomized controlled and crossover studies have demonstrated that a low-salt diet significantly reduces systolic and diastolic blood pressure and markedly decreases urinary sodium excretion. A study in middle-aged and elderly diabetic patients with hypertension showed that reducing dietary sodium intake significantly lowered blood pressure. The antihypertensive effect was independent of hypertension comorbidity or the use of antihypertensive drugs, with consistent results across subgroups and no increased risk of adverse events.
Pharmacological therapy plays an important synergistic role in salt-control strategies. RAS inhibitors (ACEI/ARB) and SGLT2 inhibitors are recommended as preferred regimens for diabetic patients with hypertension in multiple guidelines. Animal studies have shown that SGLT2 inhibitors significantly reduce blood pressure in salt-sensitive rats, and ARBs can downregulate renal SGLT2 expression and may reduce the risk of new-onset diabetes. Clinical studies have also shown that moderate salt restriction enhances the antiproteinuric effect of losartan and further reduces blood pressure.
Meta-analysis results indicate that SGLT2 inhibitors effectively reduce systolic blood pressure by approximately 4.0 mmHg and diastolic blood pressure by about 1.6 mmHg, with a dose-dependent antihypertensive effect on systolic blood pressure. They also show advantages in preventing cardiovascular events and protecting renal function.In addition, the combination of ARB and SGLT2 inhibitor has shown favorable antagonistic effects on salt-sensitive renal injury and vascular dysfunction in animal experiments. By inhibiting renal glucose and sodium reabsorption and improving insulin resistance, the ARB plus SGLT2 inhibitor regimen achieves blood pressure reduction and metabolic improvement, thereby counteracting the harmful effects of high salt in diabetes.
High salt intake plays a key role in the development and progression of diabetes and its complications. Salt restriction can lower blood pressure and ameliorate diabetic renal damage. However, salt intake may show a J-shaped relationship with all-cause mortality, and the optimal threshold for salt restriction remains to be further clarified. Mechanistically, dysfunction of the PPARδ–adiponectin–SGLT2 axis may be involved in high salt-induced diabetes-related hypertension. Based on these findings, the synergistic protective effects of ARB combined with SGLT2 inhibitor against salt-induced damage deserve in-depth investigation.