Previous studies have shown that hypertension, obesity, and insulin resistance are all associated with an increased risk of diabetes. Dietary sodium intake is closely related to blood pressure, while potassium is considered an important antagonist nutrient to sodium.
A large prospective study based on the U.S. Million Veteran Program (MVP) was recently published in Clinical Nutrition ESPEN. It systematically evaluated the associations of dietary sodium, potassium intake, and the sodium‑to‑potassium ratio with the risk of type 2 diabetes mellitus (T2DM), providing new evidence for the potential role of dietary intervention in diabetes prevention.
Dietary interventions aimed at lowering blood pressure, such as the DASH (Dietary Approaches to Stop Hypertension) diet, emphasize reduced sodium intake and increased consumption of potassium‑rich foods. This pattern has been proven to effectively lower blood pressure, especially among people with high baseline sodium intake, while also improving blood glucose, HbA1c, body weight, and lipid profiles.
Nevertheless, consistent conclusions on the relationship between dietary sodium/potassium intake and T2DM risk remain lacking, and the underlying mechanisms have not been fully clarified.
The present study found that high sodium intake was associated with an 11% increased risk of diabetes, which is consistent with previous observational studies. Earlier research suggested that high sodium intake may increase the risk of metabolic syndrome and diabetes by promoting insulin resistance.
The study also found that high sodium intake increased diabetes risk even among participants without hypertension, indicating that the effect of sodium on diabetes may be partially independent of blood pressure regulation.
The study also showed that high potassium intake was associated with a 13% reduced risk of diabetes, in an opposite direction to sodium intake. Previous studies have also linked lower serum potassium levels to an increased risk of diabetes, suggesting that potassium may play an important role in glucose metabolism.
Notably, the association for the sodium‑to‑potassium ratio was stronger: a high Na:K ratio was linked to a 21% higher risk of T2DM. This suggests that sodium‑potassium balance may better reflect the impact of diet on diabetes risk than intake of either nutrient alone, which aligns with the beneficial effects of the DASH diet (restricted sodium and increased potassium) on blood pressure and glycemia.
Furthermore, the association between the sodium‑to‑potassium ratio and diabetes risk was attenuated after adjustment for hypertension and obesity, indicating that sodium and potassium intake may exert effects partly through cardiometabolic risk factors such as blood pressure and body weight.