Mediterranean diet, healthy eating index 2005, and cognitive function in middle-aged and older Puerto Rican adults

Abstract

Adherence to a Mediterranean diet has recently been shown to protect against cognitive decline and dementia. It remains unclear, however, whether such protection extends to different ethnic groups and middle-aged individuals and how it might compare with adherence to the US Department of Agriculture's 2005 Dietary Guidelines for Americans (measured with Healthy Eating Index 2005 [HEI 2005]). This study examined associations between diet quality, as assessed by the Mediterranean diet and HEI 2005, and cognitive performance in a sample of 1,269 Puerto Rican adults aged 45 to 75 years and living in the Greater Boston area of Massachusetts. Dietary intake was assessed with a food frequency questionnaire specifically designed for and validated with this population. Adherence to the Mediterranean diet was assessed with a 0- to 9-point scale, and the HEI 2005 score was calculated with a maximum score of 100. Cognitive performance was measured with a battery of seven tests and the Mini Mental State Examination was used for global cognitive function. Greater adherence to the Mediterranean diet was associated with higher Mini Mental State Examination score (P trend=0.012) and lower likelihood (odds ratio=0.87 for each additional point; 95% CI 0.80 to 0.94; P<0.001) of cognitive impairment, after adjustment for confounders. Similarly, individuals with higher HEI 2005 score had higher Mini Mental State Examination score (P trend=0.011) and lower odds of cognitive impairment (odds ratio=0.86 for each 10 points; 95% CI 0.74 to 0.99; P=0.033). In conclusion, high adherence to either the Mediterranean diet or the diet recommended by the US Department of Agriculture 2005 Dietary Guidelines for Americans can protect cognitive function in middle-aged and older adults.

Figure 1. Odds of cognitive impairment by quintile category of diet score

Cognitive impairment was defined as: Mini Mental State Examination score <21 for those with less than high school education, <23 for those with high school completion, or <24 for those with at least some college education (14). Logistic regression was used to calculate odds ratios (OR) and 95% confidence interval (CI) for cognitive impairment with PROC LOGISTIC in SAS 9.2, adjusting for age (years), sex, educational attainment (≤ primary school, secondary school, high school, or ≥ some college), household income below threshold (yes/no), acculturation score (continuous), smoking status (never, past smoker or current smoker), physical activity score (continuous), supplement use (yes/no), taking more than 5 types of medications within the last 12 months (yes/no), body mass index (kg/m²), hypertension (yes/no), diabetes (yes/no), total cholesterol (mg/dL), high-density lipoprotein cholesterol (mg/dL), and triglycerides (mg/dL). P for trend was the P value for continuous dietary scores.