Table 3.
Evidence from cross-sectional studies according to year of publication.
| Author | Population | Measurement of Cognition (Cutoff Point) and Diet | Protein | Protein Food Source | Thiamine | Adjustments | NHMRC Level of Evidence |
|---|---|---|---|---|---|---|---|
| Ortega et al. 1997 [35], Spain | 260 free living elderly (108 men and 152 women) aged between 65 and 90 years. | MMSE (unsatisfactory: 0) 7-day weighed food record, FFQ | Protein (g/day) Men (Unsatisfactory MMSE: 81.0 ± 21.3, Satisfactory MMSE: 81.8 ± 18.7) p-value n.s Women (Unsatisfactory MMSE: 71.8 ± 14.5, Satisfactory MMSE: 73.9 ± 18.8) p-value n.s No significant association between dietary protein intake and cognitive function. |
Thiamine (mg/day) Men (Unsatisfactory MMSE: 1.18 ± 0.25, Satisfactory MMSE: 1.19 ± 0.36) Women (Unsatisfactory MMSE: 0.96 ± 0.26, Satisfactory MMSE: 1.06 ± 0.36) r = 0.2225, p-value < 0.01 Significantly higher dietary thiamine intake in participants with satisfactory scores. |
Age, Gender | IV, Neutral | |
| Lee et al. 2001 [36],, Korea | 449 free-living participants (210 men & 239 women, age >60 years. | MMSE-Korean Version (Poor: ≤19, Inadequate: 20–23, Normal: ≥24) 24-hour recall | Protein (g/day) Men (Normal: 65.1 ± 25.7, Inadequate: 63.9 ± 26.4, Poor: 60.0 ± 25.0) p-value n.s r = 0.078, p-value n.s Women (Normal: 57.0 ± 24.5, Inadequate: 58.4 ± 29.1, Poor: 42.5 ± 22.3) p-value < 0.05 r = 0.181 (p-value < 0.01) Significant association between higher dietary protein intake and better cognitive function only in women. |
Meat (g/day) Men (Normal: 39.2 ± 47.4, Inadequate: 40.9 ± 50.2, Poor: 46.7 ± 47.3) p-value n.s r = −0.004, p-value n.s Women (Normal: 37.7 ± 52.5, Inadequate: 34.6 ± 57.1, Poor: 20.7 ± 31.1) p-value n.s r = 0.096, p-value n.s No significant association between meat intake and cognitive function. |
Thiamine (mg/day) Men (Normal: 0.95 ± 0.35, Inadequate: 0.91 ± 0.34, Poor: 0.82 ± 0.27), r = 0.083, p-value n.s Women (Normal: 0.91 ± 0.39, Inadequate: 0.90 ± 0.63, Poor: 0.71 ± 0.35) p-value < 0.05, r = 0.125, p-value n.s Significantly higher intake of dietary thiamine in women normal cognition participants than cognitively impaired participants but not significant in men. |
Age | IV, Neutral |
| Requejo et al. 2003 [37], Spain | 168 free-living elderly at day centres with normal cognition, age between 65 and 90 years. | MMSE (unsatisfactory: <28, satisfactory: ≥28) 7-day food diary and 5-day weighted food record of lunch | Meat (g/day) Age ≥ 75 years (MMSE < 28: 126.3 ± 66.6, MMSE ≥ 28: 98.9 ± 32.1) Age < 75 years (MMSE < 28: 127.6 ± 60.9, MMSE ≥ 28: 138.5 ± 77.7) p-value n.s No significant association between higher meat consumption with better cognitive function. |
Thiamine Age ≥ 75 years (MMSE < 28: 1.05 ± 0.29, MMSE ≥ 28: 0.96 ± 0.23) Age < 75 years (MMSE < 28: 1.05 ± 0.29, MMSE ≥ 28: 1.12 ± 0.34) p-value < 0.1 almost sig r = 0.2332, p-value < 0.01 Significant association between higher dietary thiamine intake and better cognitive function. |
None | IV, Neutral | |
| Rahman et al. 2007 [38], USA | 1056 community dwelling elderly, mean age = 67. | MSQ (cognitive impairment: <9, normal: ≥9) Verbal FFQ (Yes: Once or twice a week, or most days, or everday. No: Less often than once a week, or never.) |
Pork, beef, lamb (g/day) Yes (n = 904) No (n = 152) OR = 1.11 (0.67, 1.84) p-value n.s Chicken and turkey Yes (n = 916) No (n = 140) OR= 0.81 (0.48, 1.36) p-value n.s No significant association between pork, beef, lamb, chicken or turkey. |
Age, Gender, Education and Other dietary factors | IV | ||
| Mori et al. 2010 [39], Japan | 179 community dwelling elderly, aged ≥65 years | SF-36 MCS (High MCS and Low MCS based on standardised score classified by age, 60–69 years = 52.0 and ≥70 years = 51.7 ) Semi-quantitative FFQ |
Protein (g/day) (High: 74.5 ± 1 Low: 73.5 ± 1.6) p-value n.s No significant association between dietary protein intake and cognitive function. |
Meat (g/day) (High: 44.0 ± 3.3 Low: 55.3 ± 5.3) p-value n.s No significant association between meat and cognition. |
Age, Gender | IV, Neutral | |
| Aparicio Vizuete et al. 2010 [40], Spain | 178 institutionalised elderly, age ≥ 65 years. | SMPSQ (0 = No error, >0 = Error) 7-day Weighed Food Records | Protein (g/day) Age < P50 years (No error: 71.01 ± 14.30, Error: 67.63 ± 12.68) Age ≥ P50 years (No error: 70.02 ± 12.89, Error: 67.98 ± 10.67) p-value n.s r2 = 0.5899 p-value < 0.001 Significantly higher dietary protein and meat intake in participants with better cognitive functioning. |
Meat Age < P50 years (No error: 98.14 ± 41.67, Error: 105.55 ± 40.38) Age ≥ P50 years (No error: 93.05 ± 39.81, Error: 88.90 ± 35.73) p-value n.s r2 = 0.1086 p-value < 0.001 Significantly higher meat intake in participants with poorer cognitive functioning. |
Thiamine (mg/day) Age < P50 years (No error: 1.11 ± 0.28, Error: 1.10 ± 0.24) Age ≥ P50 years (No error: 1.12 ± 0.25, Error: 1.09 ± 0.25) p-value n.s r2 = 0.3180 p-value < 0.001 Significant association between higher dietary thiamine intake and better cognitive function. |
Energy intake and Education level | IV, Neutral |
| Katsiardanis et al. 2013 [41], Greece | 557 free-living elderly (m = 237, w = 320), age > 65 years | MMSE (cognitive impairment: <24, normal: ≥24), GDS. FFQ and Semi-quantitative FFQ |
Protein (g/day) Men (Cognitive impairment: 82.5 ± 28.84, Normal: 81.0 ± 23.57) p-value n.s OR = 1.36 (0.92–2.02), p-value n.s Women (Cognitive impairment: 75.5 ± 24.34, Normal: 74.8 ± 28.59) p-value n.s OR = 0.88 (0.56–1.37), p-value n.s No significant association between dietary protein intake and cognitive functioning. |
Meat and Meat product Men (Cognitive impairment: 24.0 ± 14.67, Normal: 22.0 ± 10.25) p-value n.s OR = 1.03 (0.84–1.27), p-value n.s Women (Cognitive impairment: 18.8 ± 11.47, Normal: 19.8 ± 12.27) p-value n.s OR = 0.96 (0.81–1.16), p-value n.s No significant association between meat and meat products with cognitive function. |
Thiamine Men OR = 1.05 (0.76–1.44) p-value n.s Women OR = 1.16 (0.65–1.38) p-value n.s No significant association between dietary thiamine intake and cognitive function. |
Age, Education, Social Activity, Smoking, Metabolic syndrome, Geriatric Depression Scale and MedDiet Score. OR adjusted for core models and energy intake. | IV, Neutral |
Abbrevations: DSM, Diagnostic and Statistical Manual of Mental Disorders; GDS, Geriatric Depression Scale; MMSE, Mini Mental State Examination; PMSQ, Pfeiffer’s Mental Status Questionnaire; FFQ, Food Frequency Questionnaire; SF-36 MCS, Short Form (36) Mental Component Score; SPMSQ, Short Portable Mental State Questionnaire.