TABLE 3.
Nut consumption and cognitive performance in older people (aged ≥60 y).
| Author, year, country | Study design | Study population | Nut intake (type, amount) | Comparison group | Cognitive measure | Findings |
|---|---|---|---|---|---|---|
| Arab & Ang, 2015, USA (22) | Cross-sectional | n = 7337 free-living (≥60 y) | Walnut (WWHC, WWON) | Nonconsumers | Story recall test | WWHC: 8.3 (β: 7.09; 95% CI: 0.6, 13.6; P = 0.031)WWON: 10.7 (β: 8.11; 95% CI: 3.5, 12.7; P = 0.0011) |
| Digit-symbol substitution test | WWHC: 11.3 (β: 7.31; 95% CI: 0.09, 14.6; P = 0.051)WWON: 11.8 (β: 4.82; 95% CI: 0.89, 8.72; P = 0.021) | |||||
| Cardoso et al., 2016, Brazil (36) | RCT, parallel-arm (24 wk) | n = 20 MCI (≥60 y) | Brazil nut (1 kernel/d, ∼5 g) | Nut-free diet | Verbal fluencyConstructional praxis | EF: 1.33; P = 0.007EF: 1.01; P = 0.031 |
| Boston naming test | No difference between groups | |||||
| Word list learning test | No difference between groups | |||||
| Word list recall | No difference between groups | |||||
| CERAD total score | No difference between groups | |||||
| De Amicis et al., 2018, Italy (23) | Cross-sectional | n = 279 free-living (≥65 y) | Total nuts | Risk of MCI | OR: 0.3; 95% CI 0.1, 0.7; P = 0.005 | |
| Rabassa et al., 2020, Italy (33) | Prospective cohort (3 y) | n = 119 free-living (≥65 y) | Walnuts, almonds, hazelnuts, peanuts (combined) | Nonconsumers | MMSERisk of cognitive decline | Mean difference: 1.5; EF: 0.47; P = 0.012β: 0.25; 95% CI: 0.04, 0.46; P = 0.0182OR: 0.78; 95% CI: 0.61, 0.99; P = 0.0432 |
| Sala-Vila et al., 2020, USA and Spain (41) | RCT, parallel-arm (2 y) | n = 657 free-living (66–79 y) | Walnut, 15% daily energy (30–60 g/d) | Nut-free diet | Global cognition | No difference between groups (significant difference in the Barcelona site: mean difference: 0.07; P = 0.016)3 |
| Perception | No difference between groups (significant difference in the Barcelona site: mean difference: 0.2; P = 0.005)3 | |||||
| Language | No difference between groups3 | |||||
| Memory | No difference between groups3 | |||||
| Frontal function | No difference between groups3 | |||||
| Samieri et al., 2013, USA (29) | Prospective cohort (average 4 y) | n = 6174 free-living women (≥66 y) | Total nuts | Average of 3 time points: quintiles of nut intake | Global cognitive functionVerbal memory | No association4 No association4 |
| Change over time: quintiles of nut intake | Global cognitive function | No association4 | ||||
| Verbal memory | No association4 | |||||
| Zhao et al., 2015, China (35) | Case-control | n = 404 (98 MCI, 306 healthy controls) (60–90 y) | Total nuts | MoCA | Nut intake was not different between MCI and control groups (P > 0.05) |
Adjusted for age, gender, race, education, BMI, smoking, alcohol consumption, and physical activity.
Adjusted for sex, age, baseline score of cognitive function, depressive symptoms, education, BMI, physical activity, smoking status, energy intake, alcohol consumption, stroke, cardiovascular disease, hypertension, and diabetes.
Adjusted for age, gender, education, APOE ε4 allele, ever smoking, physical activity, BMI, diabetes, dyslipidemia, hypertension, Hamilton Depression Rating Scale score.
Adjusted for MedDiet score, treatment arm (in the original RCT), age, race, education, income, energy intake, physical activity, BMI, smoking status, diabetes, hypertension, hypercholesterolemia, hormone use, and depression. CERAD, Consortium to Establish a Registry for Alzheimer's Disease; EF, Cohen's d effect size; MCI, mild cognitive impairment; MMSE, Mini-Mental State Examination; MoCA, Montreal Cognitive Assessment; RCT, randomized controlled trial; WWHC, walnuts with high certainty; WWON, walnuts with other nuts.