African American (AA) adults have about twice the risk of developing dementia compared with white adults. However, evidence on dietary modification in preventing cognitive decline from diverse populations focusing on AA adults is minimal. We aimed to evaluate the association between a plant-based diet and the rate of cognitive decline in a population-based sample of AA and white adults. This study consisted of 3337 participants from the Chicago Health and Aging Project (60% AA participants, 64% female). Plant-based diet quality was evaluated by the overall plant-based diet index (PDI), the healthful PDI (hPDI), and the unhealthful PDI (uPDI). Global cognition was assessed using a composite score of 4 individual tests of cognition. We used mixed models to examine the associations of PDI, hPDI, and uPDI with the rates of decline in global cognition, perceptual speed, and episodic memory. Models were adjusted for age, sex, presence of apoE e4 allele, lifestyle factors including education, cognitive activities, smoking status, calorie intake, risk factors for cardiovascular disease, time, and the interaction terms of time × each covariate. AA and white participants had various dietary patterns. Higher hPDI was associated with a slower rate of decline in global cognition, perceptual speed, and episodic memory in AA participants but not white participants. AA study participants in the highest quintile of hPDI had significantly slower rates of global cognitive decline (β: 0.0183 ± 0.0086; P = 0.032), perceptual speed (β: 0.0179 ± 0.0088; P = 0.04), and episodic memory (β: 0.0163 ± 0.0118; P = 0.04) than individuals in the lowest quintile of hPDI. There were no associations of either PDI or uPDI with the rate of cognitive decline in either racial group. A healthy plant-based diet was associated with a slower rate of decline in global cognition, perceptual speed, and episodic memory in AA adults.

Background: The Dietary Approaches to Stop Hypertension (DASH) diet has been shown to reduce biomarkers of cardiovascular disease. We aimed to characterize the time course of change in biomarkers of cardiac injury (high‐sensitivity cardiac troponin I), cardiac strain (NT‐proBNP [N‐terminal pro‐B‐type natriuretic peptide]), and inflammation (hs‐CRP [high‐sensitivity C‐reactive protein]) while consuming the DASH diet. Methods and Results: The DASH‐Sodium trial was a randomized controlled trial of 412 adults with elevated blood pressure or hypertension. Participants were randomly assigned to 12 weeks of the DASH diet or a typical American diet. Energy intake was adjusted to maintain body weight. Measurements of high‐sensitivity cardiac troponin I, NT‐proBNP, and hs‐CRP were performed in stored serum specimens, collected at baseline and ≈4, 8, and 12 weeks after randomization. In both the control diet and DASH diet, levels of NT‐proBNP decreased; however, there was no difference between diets ( P ‐trend compared with control=0.22). On the DASH diet versus control, levels of high‐sensitivity cardiac troponin I decreased progressively during follow‐up ( P‐ trend compared with control=0.025), but a statistically significant between‐diet difference in change from baseline levels was not observed until week 12 (% difference, 17.78% [95% CI, −29.51% to −4.09%]). A similar pattern was evident for hs‐CRP ( P‐ trend compared with control=0.01; % difference at week 12, 19.97% [95% CI, −31.94% to −5.89%]). Conclusions: In comparison with a typical American diet, the DASH diet reduced high‐sensitivity cardiac troponin I and hs‐CRP progressively over 12 weeks. These results suggest that the DASH diet has cumulative benefits over time on biomarkers of subclinical cardiac injury and inflammation. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT00000608.

There is emerging evidence linking fruit and vegetable consumption and cognitive function. However, studies focusing on the nutrients underlying this relationship are lacking. We aim to examine the association between plasma nutrients and cognition in a population at risk for cognitive decline with a suboptimal diet. The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) trial is a randomized controlled intervention that examines the effects of the MIND diet to prevent cognitive decline. The primary outcome is global cognition. A multivariate linear model was used to investigate the association between blood nutrients and global and/or domain-specific cognition. The model was adjusted for age, sex, education, study site, smoking status, cognitive activities and physical activities. High plasma α-carotene was associated with better global cognition. Participants in the highest tertile of plasma α-carotene had a higher global cognitionzscore of 0⋅17 when compared with individuals in the lowest tertile (P0⋅002). Circulating α-carotene levels were also associated with higher semantic memory scores (Pfor trend 0⋅007). Lutein and zeaxanthin (combined) was positively associated with higher semantic memory scores (Pfor trend 0⋅009). Our study demonstrated that higher α-carotene levels in blood were associated with higher global cognition scores in a US population at risk for cognitive decline. The higher α-carotene levels in blood reflected greater intakes of fruits, other types of vegetables and lesser intakes of butter and margarine and meat. The higher circulating levels of lutein plus zeaxanthin reflected a dietary pattern with high intakes of fruits, green leafy, other vegetables and cheese, and low consumption of fried foods. Objective nutrient markers in the blood can better characterize dietary intake, which may facilitate the implementation of a tailored dietary intervention for the prevention of cognitive decline.

Few studies have evaluated the association between a healthful plant-based diet and health-related quality of life (HRQoL). We followed 50 290 women in the Nurses’ Health Study (NHS; 1992–2000) and 51 784 women in NHSII (1993–2001) for 8 years to investigate changes in plant-based diet quality in relation to changes in physical and mental HRQoL. Plant-based diet quality was assessed by three plant-based diet indices: overall plant-based diet index (PDI), healthful PDI (hPDI) and unhealthful PDI (uPDI). Physical and mental HRQoL were measured by physical component score (PCS) and mental component score (MCS) of the 36-Item Short Form Health Survey. Diet was assessed 2 years before the HRQoL measurements and both were updated every 4 years. The associations between 4-year changes in PDIs and HRQoL were evaluated. Each 10-point increase in PDI was associated with an improvement of 0·07 (95 % CI 0·01, 0·13) in PCS and 0·11 (95 % CI 0·05, 0·16) in MCS. A 10-point increase in hPDI was associated with an increment of 0·13 (95 % CI 0·08, 0·19) in PCS and 0·09 (95 % CI 0·03, 0·15) in MCS. Conversely, a 10-point increase in uPDI was associated with decreases in PCS and MCS (−0·07 (95 % CI −0·12, −0·02) and −0·10 (95 % CI −0·16, −0·05), respectively). Compared with a stable diet, an increase in hPDI was significantly associated with improvements in physical HRQoL in older women and with mental HRQoL in younger women. In conclusion, adherence to a healthful plant-based diet was modestly associated with improvements in both physical and mental dimensions of HRQoL.