Association of dietary sodium, potassium, sodium/potassium, and salt with objective and subjective cognitive function among the elderly in China: A prospective cohort study

Abstract

Background & aims

Previous evidence varied on the relationship of dietary sodium, potassium, sodium/potassium, and salt with cognitive function. This study aimed to explore the associations of sodium, potassium, sodium/potassium, and salt intakes with cognitive function among the elderly in China.

Methods

Data were accessed from the database of the 1997–2006 China Health and Nutrition Survey, including 4213 participants aged at least 50 years at baseline. Dietary data at individual and household levels were collected using the method of 24-h dietary recall in three consecutive days. Cognitive function was measured through objective and subjective methods. Linear regression models and multinomial logistic regression models were established to elucidate the association of dietary sodium, potassium, sodium/potassium, and salt with cognitive function. Mediation effect analysis and substitution analysis were also conducted.

Results

Higher potassium intakes in Q3 (Median: 1653.3 g/day, β = 1.366, 95% confidence interval [CI]: 0.845 to 1.887) and Q4 (Median: 2181.4 g/day, β = 1.454, 95% CI: 0.865 to 2.044) were significantly associated with higher cognitive test score compared with Q1 (Median: 1053.7 g/day). Sodium/potassium intake in Q3 (Median: 3.8, β = −0.791, 95% CI: -1.264 to −0.317) and Q4 (Median: 5.5, β = −0.909, 95% CI: -1.401 to −0.417) were inversely associated with the cognitive test score compared with Q1 (Median: 2.0). Higher dietary sodium and sodium/potassium intakes were associated with a higher risk of a self-reported poor and deteriorated memory during the past 12 months. Additionally, higher potassium intakes were significantly associated with a lower risk of deteriorated memory. The associations of dietary potassium and sodium/potassium were mediated by CCVD, and average cognitive test score increased by about 1 point after replacing 1000 mg/day of sodium with an equal intake of potassium.

Conclusions

Restricting sodium and increasing potassium, and keeping the balance of dietary sodium and potassium are encouraged to prevent cognitive decline and dementia in the elderly.