Introduction
Methods
Study design and recruitment
Cognitive assessment
Task switching
2-back task
Tonic alertness
Statistical analyses
Results
Participants
h-mGI (n 105) | p | m-hGI (n 107) | p | |||
---|---|---|---|---|---|---|
Period 1 | Period 2 | Period 1 | Period 2 | |||
Female n (%) | 47 (44.8) | 40 (37.7) | ||||
Glycemic load | 99 ± 44 | 66 ± 33 | < 0.001 | 75 ± 37 | 100 ± 79 | < 0.001 |
Dietary GI of lunch and cognition
Switch task
mGI | hGI | Treatment difference (mGI–hGI) | p | pd | |
---|---|---|---|---|---|
Switch (n 179) | |||||
Switch costs [s]b | |||||
Mean (SE) | 167 (4.32) | 170 (4.32) | − 2.18 (5.52) | 0.693c | 1.0 |
95% CI | 159, 176 | 161, 178 | − 13.1, 8.71 | ||
Visual search letters [s]a,b | |||||
Mean (SE) | 10.5 (0.02) | 10.5 (0.02) | − 0.004 (0.02) | 0.859c | 1.0 |
95% CI | 10.4, 10.5 | 10.4, 10.5 | − 0.04, 0.04 | ||
Visual search numbers [s]b | |||||
Mean (SE) | 10.9 (0.02) | 10.9 (0.02) | − 0.02 (0.02) | 0.218 | 1.0 |
95% CI | 10.9, 10.9 | 10.9, 11.0 | − 0.05, 0.01 | ||
2-back (n 210) | |||||
RT [ms] | |||||
Mean (SE) | 463 (9.45) | 470 (9.45) | − 6.65 (8.41) | 0.430 | 1.0 |
95% CI | 444, 482 | 451, 488 | − 23.2, 9.93 | ||
Ratio of missings (%)b | |||||
Mean (SE) | 5.06 (0.14) | 5.32 (0.14) | − 0.26 (0.13) | 0.047c | 0.470 |
95% CI | 4.79, 5.33 | 5.05, 5.59 | − 0.51, − 0.003 | ||
Ratio of false alarms (%)b | |||||
Mean (SE) | 4.38 (0.19) | 4.29 (0.19) | 0.09 (0.11) | 0.388c | 1.0 |
95% CI | 4.01, 4.75 | 3.92, 4.66 | − 0.12, 0.30 | ||
Alertness (n 211) | |||||
Mean RT [ms]b | |||||
Mean (SE) | 5.67 (0.02) | 5.66 (0.02) | 0.002 (0.02) | 0.886c | 1.0 |
95% CI | 5.63, 5.70 | 5.63, 5.70 | − 0.03, 0.03 | ||
Deviation of RT [ms]b | |||||
Mean (SE) | 4.95 (0.04) | 4.98 (0.04) | − 0.03 (0.05) | 0.557c | 1.0 |
95% CI | 4.86, 5.03 | 4.89, 5.06 | − 0.12, 0.07 | ||
Count of omission errors (n)b | |||||
Mean (SE) | 0.81 (0.02) | 0.79 (0.02) | 0.02 (0.02) | 0.365c | 1.0 |
95% CI | 0.77, 0.84 | 0.75, 0.83 | − 0.02, 0.06 | ||
Count of commission errors (n)b | |||||
Mean (SE) | 1.55 (0.06) | 1.51 (0.06) | 0.03 (0.06) | 0.540 | 1.0 |
95% CI | 1.43, 1.67 | 1.39, 1.63 | − 0.08, 0.14 |
2-back task
Alertness
Estimated lunch GL
mGI | hGI | Treatment difference (mGI–hGI) | p | pd | |
---|---|---|---|---|---|
Switch (n 179) | |||||
Switch costs [s]b | |||||
Mean (SE) | 167 (4.41) | 170 (4.41) | – 2.67 (5.77) | 0.644c | 1.0 |
95% CI | 158, 176 | 161, 178 | – 14.0, 8.71 | ||
Visual search letters [s]a,b | |||||
Mean (SE) | 10.5 (0.02) | 10.5 (0.02) | 0.00 (0.02) | 0.983c | 1.0 |
95% CI | 10.4, 10.5 | 10.4, 10.5 | – 0.04, 0.04 | ||
Visual search numbers [s]b | |||||
Mean (SE) | 10.9 (0.02) | 10.9 (0.02) | – 0.01 (0.02) | 0.425 | 1.0 |
95% CI | 10.9, 11.0 | 10.9, 11.0 | – 0.05, 0.02 | ||
2-back (n 210) | |||||
RT [ms] | |||||
Mean (SE) | 461 (9.62) | 471 (9.62) | – 9.88 (9.07) | 0.277 | 1.0 |
95% CI | 442, 480 | 452, 490 | – 27.7, 8.00 | ||
Ratio of missings (%)b | |||||
Mean (SE) | 5.09 (0.14) | 5.29 (0.14) | – 0.21 (0.14) | 0.145c | 1.0 |
95% CI | 4.81, 5.37 | 5.02, 5.57 | – 0.48, 0.71 | ||
Ratio of false alarms (%)b | |||||
Mean (SE) | 4.41 (0.19) | 4.27 (0.19) | 0.14 (0.12) | 0.234c | 1.0 |
95% CI | 4.03, 4.78 | 3.89, 4.64 | – 0.09, 0.37 | ||
Alertness (n 211) | |||||
Mean RT [ms]b | |||||
Mean (SE) | 5.67 (0.02) | 5.66 (0.02) | 0.01 (0.02) | 0.458c | 1.0 |
95% CI | 5.64, 5.71 | 5.62, 5.70 | – 0.02, 0.05 | ||
Deviation of RT [ms]b | |||||
Mean (SE) | 4.96 (0.04) | 4.96 (0.04) | 0.002 (0.05) | 0.971c | 1.0 |
95% CI | 4.88, 5.05 | 4.88, 5.05 | – 0.10, 0.10 | ||
Count of omission errors (n)b | |||||
Mean (SE) | 0.80 (0.02) | 0.79 (0.02) | 0.01 (0.02) | 0.587c | 1.0 |
95% CI | 0.76, 0.84 | 0.75, 0.83 | – 0.03, 0.06 | ||
Count of commission errors (n)b | |||||
Mean (SE) | 1.55 (0.06) | 1.51 (0.06) | 0.05 (0.06) | 0.416 | 1.0 |
95% CI | 1.43, 1.68 | 1.38, 1.63 | – 0.07, 0.17 |