TABLE 4.
Nut consumption and cognitive performance in older people aged ≥70 y
| Author, year, country | Study design | Study population | Nut intake (type, amount) | Comparison group | Cognitive measure | Findings |
|---|---|---|---|---|---|---|
| Nurk et al., 2010, Norway (26) | Cross-sectional | n = 2031, free-living (70–74 y) | Total nuts | Nonconsumers | Kendrick Object Learning Test | No difference between groups1 |
| Trail making test A | No difference between groups1 | |||||
| Digit Symbol Test | No difference between groups1 | |||||
| Block design | No difference between groups1 | |||||
| MMSE | No difference between groups1 | |||||
| Controlled Oral Word Association Test | No difference between groups1 | |||||
| O'Brien et al., 2014, USA (32) | Prospective cohort (6 y) | n = 15,467 female nurses (≥70 y) | Total nuts | Average of 4 time points: nonconsumers x consumers ≥5 times/wk | Telephone interview for cognitive statusGlobal cognition | Mean difference: 0.21; 95% CI: –0.10, 0.52; P-trend = 0.022Mean difference: 0.08; 95% CI: 0.0, 0.15; P-trend = 0.0032 |
| Global cognition | Mean difference: 0.08; 95% CI: 0.0, 0.15; P-trend = 0.0032 | |||||
| Verbal memory | Mean difference: 0.09; 95% CI: 0.01, 0.17; P-trend = 0.0052 | |||||
| Change over time: quintiles of nut intake | Telephone interview for cognitive status (rate of decline) | No association2 | ||||
| Global cognition (rate of decline) | No association2 | |||||
| Verbal memory (rate of decline) | No association2 | |||||
| Walnuts | Average of 4 time points: nonconsumers x consumers 1 time/wk | Telephone interview for cognitive statusGlobal cognition | No association2No association2 | |||
| Verbal memory | No association2 | |||||
| Change over time: quintiles of nut intake | Telephone interview for cognitive status | No association2 | ||||
| Global cognition | No association2 | |||||
| Verbal memory | No association2 | |||||
| Samieri et al., 2013, USA (30) | Prospective cohort (6 y) | n = 16,058 free-living women (≥70 y) | Total nuts | Average of 4 time points: nonconsumers x consumers ≥5 times/wk | Global cognitionVerbal memory score | Mean difference: 0.02; 95% CI: –0.03, 0.06; P-trend = 0.023Mean difference: 0.01; 95% CI: –0.04, 0.06; P-trend = 0.053 |
| Change over time: quintiles of nut intake | Global cognitionVerbal memory score | No association3No association3 | ||||
| Wang et al., 2010, China (28) | Cross-sectional | n = 364 free-living (≥90 y) | Total nuts | Risk of MCI | No association4 |
Adjusted for sex, education, vitamin supplement use (multivitamins, folic acid, vitamins B, C, D, or E), smoking status, history of CVD, diabetes, intakes of dairy products, meat, fish, total fat, and protein.
Adjusted for age, education, time span between cognitive interviews, use of antidepressant medication, smoking status, physical activity, energy intake, alcohol intake, BMI, multivitamin use, history of diabetes, hypertension, hypercholesterolemia, and myocardial infarction.
Adjusted for age, treatment arm (in the original RCT), education, income, energy intake, physical activity, BMI, smoking status, diabetes, hypertension, hypercholesterolemia, hormone use, and depression.
Adjusted for gender, age, education, physical activity, blood pressure (systolic and diastolic), BMI, fasting plasma glucose, total cholesterol, triglycerides, HDL cholesterol and LDL cholesterol, smoking status, alcohol and tea consumption. MCI, mild cognitive impairment; MMSE, Mini-Mental State Examination; RCT, randomized controlled trial.