Avocado Consumption Increases Macular Pigment Density in Older Adults: A Randomized, Controlled Trial
Abstract
:1. Introduction
2. Materials and Methods
2.1. Subjects
2.2. Experimental Design
2.3. Study Protocol
2.4. Serum Analysis for Carotenoids and Biomarkers of Oxidative Stress and Inflammation
2.5. Lipoprotein Analysis
2.6. Measurement of Macular Pigment Density
2.7. Cognitive Tests
2.8. Sample Size Calculation
2.9. Statistical Analyses
3. Results
3.1. Subject Characteristics
3.2. Serum Analysis for Carotenoids and Biomarkers of Oxidative Stress and Inflammation
3.3. Lipoproteins
3.4. Macular Pigment Density
3.5. Cognitive Measures
3.6. Relationship between MPD and Cognitive Measures
4. Discussion
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Cognitive Test | Description | Outcome Measures |
---|---|---|
Attention Tests | ||
Test | Score | |
Choice Reaction Time (CRT) | Two-choice reaction time test with two possible stimuli and two possible responses | Mean correct latency (response speed) |
Rapid Visual Information Processing (RVIP) | Test of sustained attention | A’—Signal detection measure of sensitivity to the target B”—Signal detection measure of the strength of trace required to elicit a response |
Visual Memory Tests | ||
Test | Score | |
Delayed Match to Sample (DMS) | Test of simultaneous and delayed matching to sample | Percent correct (all delays) |
Paired Associates Learning (PAL) | Assesses visual memory and new learning | Total errors (adjusted) Stages completed |
Executive Function, Working Memory, and Planning Tests | ||
Test | Score | |
Spatial Span (SSP) | Assesses working memory | Span length |
Spatial Span Reverse (SSP-R) | Assesses working memory | Span length |
Spatial Working Memory (SWM) | Tests ability to retain spatial information and manipulate items in working memory | Between errors strategy |
Stockings of Cambridge (SOC) | Test of spatial planning and spatial working memory | Problems solved in minimum moves; Mean total thinking time: four moves |
Avocado | Control | |
---|---|---|
Age, years, mean (SD) | 63.3 (11.1) | 62.5 (9.2) |
Body mass index, kg/m2, mean (SD) | 24.1 (3.1) | 24.2 (2.4) |
Education (%), some college or greater | 85 | 75 |
Sex (female/male) | 14/6 | 11/9 |
Dietary lutein/zeaxanthin, mg/day, mean (SD) | 3.0 (3.1) | 2.8 (2.7) |
Dietary protein, g/day (SD) | 75.3 (41.9) | 68.2 (44.0) |
Dietary fat, g/day (SD) | 74.3 (35.0) | 66.2 (41.4) |
Dietary carbohydrate, g/day (SD) | 246.0 (130.5) | 228.3 (130.8) |
Dietary monounsaturated fatty acids, g/day (SD) | 27.4 (12.8) | 22.3 (11.5) |
Avocado | Control | |||||
---|---|---|---|---|---|---|
Baseline | 3 Months | 6 Months | Baseline | 3 Months | 6 Months a | |
Lutein (nmol/L) | 330 (139) | 423 (111) b | 414 (147) b | 322 (134) | 352 (153) | 371 (168) c |
Zeaxanthin (nmol/L) | 63 (17) | 69 (45) | 57 (30) | 65 (33) | 83 (47) d | 78 (40) e |
Macular pigment denisty (MPD), OD | 0.393 (0.142) | 0.484 (0.178) f | 0.494 (0.137) b | 0.380 (0.173) | 0.445 (0.177) g | 0.424 (0.149) |
Serum cholesterol (mg/dL) | 219 (52) | 224 (56) | 209 (43) | 200 (46) | 209 (42) | 205 (54) |
high density lipoproteins (HDL) (mg/dL) | 57 (21) | 61 (23) | 61 (22) | 58 (16) | 56 (14) | 57 (18) |
low-density lipoproteins (LDL) (mg/dL) | 129 (43) | 135 (37) | 131 (25) | 132 (37) | 137 (37) | 137 (45) |
Triglycerides (mg/dL) | 86 (64) | 99 (82) | 79 (57) | 84 (55) | 94 (84) | 93 (58) |
C-reactive protein, mg/L | 2.0 (2.8) | 2.0 (2.8) | 1.7 (1.8) | 1.3 (1.0) | 2.3 (2.4) | 1.6 (1.6) |
β-Amyloid, pg/mL | 7.7 (2.8) | 7.9 (2.7) | 7.5 (2.7) | 9.6 (5.0) | 9.2 (5.2) | 9.7 (5.2) |
LDL Oxidative lagtime (min) | 88.2 (22.9) | 91.2 (14.2) | 89.1 (17.3) | 84.5 (26.6) | 86.2 (16.9) | 85.0 (18.7) |
Avocado | Control | |||||
---|---|---|---|---|---|---|
Baseline | 3 Months | 6 Months | Baseline | 3 Months | 6 Months | |
CRT mean latency msec | 347.4 (55.4) | 355.0 (53.2) | 342.8 (56.8) | 356.0 (70.6) | 367.0 (76.5) | 359.1 (75.5) |
RVIP signal detection 4 | 0.86 (0.21) | 0.92 (0.04) | 0.93 (0.04) | 0.90 (0.05) | 0.92 (0.05) | 0.92 (0.05) |
DMS percent correct all delays | 84.7 (12.8) a | 86.0 (10.4) | 84.7 (13.5) | 80.0 (9.4) | 85.3 (11.2) | 83.0 (12.1) |
PAL total errors (adjusted) 2 | 28.0 (17.8) | 17.5 (14.2) c | 19.5 (15.5) d | 27.3 (18.7) | 17.9 (17.0) e | 16.8 (14.9) e |
SS Forward highest span | 5.8 (1.2) | 6.2 (1.3) | 5.8 (1.2) | 5.8 (1.1) | 6.1 (1.3) | 6.1 (1.5) |
SS Reverse highest span 1 | 5.3 (1.6) | 5.3 (1.3) | 5.5 (1.4) | 5.0 (1.0) | 5.6 (1.4) | 5.7 (2.0) b |
SWM errors 3 | 52.5 (19.6) | 43.6 (19.8) f | 48.4 (17.3) | 50.7 (19.1) | 47.80 (17.6) | 42.1 (19.8) |
SOC # completed in minimum moves 5 | 7.8 (2.1) | 8.7 (2.3) | 8.8 (2.2)c | 8.0 (2.0) | 8.4 (2.2) | 9.0 (2.7) |
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Scott, T.M.; Rasmussen, H.M.; Chen, O.; Johnson, E.J. Avocado Consumption Increases Macular Pigment Density in Older Adults: A Randomized, Controlled Trial. Nutrients 2017, 9, 919. https://doi.org/10.3390/nu9090919
Scott TM, Rasmussen HM, Chen O, Johnson EJ. Avocado Consumption Increases Macular Pigment Density in Older Adults: A Randomized, Controlled Trial. Nutrients. 2017; 9(9):919. https://doi.org/10.3390/nu9090919
Chicago/Turabian StyleScott, Tammy M., Helen M. Rasmussen, Oliver Chen, and Elizabeth J. Johnson. 2017. "Avocado Consumption Increases Macular Pigment Density in Older Adults: A Randomized, Controlled Trial" Nutrients 9, no. 9: 919. https://doi.org/10.3390/nu9090919