Cognitive function and elderly macronutrient intakes from rural diets in Qingdao, China.

Background and Objectives: Energy provided by macronutrients plays a key role in healthy aging. This study therefore explored the association between macronutrients and cognitive function in elderly populations in rural areas of Qingdao, China.
Methods and Study Design: This study included 1,504 participants over the age of 65 recruited from Licha Town, Qingdao City, China. Dietary intake was measured using the Food Frequency Questionnaire, and cognitive function was assessed using the Mini-Mental State Examination. Logistic regression models were used to evaluate the association between dietary macronutrient intake and cognitive function. In addition, restricted cubic bars were applied to determine the dose-response relationship between macronutrient ratios and cognitive performance.
Results: A total of 877 adults over the age of 65 were included. After adjusting the weighted multiple variables, significant positive associations were revealed between protein and moderate carbohydrate intake and cognitive ability, but a negative association between fat intake and cognitive performance was identified. After calculating the daily energy supply ratio, similar associations were revealed between fat and protein intake and cognitive function. Furthermore, the ratio of proteins to carbohydrates had a U-shaped relationship with cognitive function (pnonlinearity=0.674), whereas the ratio of proteins to fats was L-shaped with lower cognitive function (pnonlinearity<0.001). Compared with the lowest quartile of the ratio of protein to fat intake, the weighted adjusted OR (95% CI) of the highest quartile was 0.509 (0.314, 0.827) for low cognitive performance.
Conclusions: With an adequate carbohydrate supply, appropriately increasing dietary protein intake and reducing fat intake might benefit the cognitive function of elders in rural areas.