Table 5.
Summary of observational studies assessing fermented dairy product consumption and cognitive function.
| Participants | Numbers | Design | Diet measures | Cognitive tests | Outcome | Results | References |
|---|---|---|---|---|---|---|---|
| Elderly (age not defined); from the US | 1,056 (345 men, 711 women) | Cross-sectional study; single in-person session with each participant | 10-item FFQ | Mental status questionnaire | Positive | Cheese consumption at least weekly reduced likelihood of mental status score of < 9 (AOR = 0.68, P = 0.47) | Rahman et al. (31) |
| 60+ years; living in the US | 6,471 | Cross-sectional study; from survey records of single in-person session with each participant | 24 h dietary recall | Story recall test (4,282), digit-symbol substitution test (2,189) | Positive | Those who consumed cheese had higher story recall test scores (Cohen's d = 0.12a) | Park and Fulgoni (17) |
| 50+ years; living in South Korea | 276 (105 men, 171 women) | Cross-sectional study; single in-person session with each participant | 112-item FFQ | MMSE | Positive | Increased liquid and curd yogurt consumption reduced odds of MCI (AOR = 0.264, P = 0.019 for liquid and AOR = 0.263, P = 0.015) | Kim and Yun (21) |
| 60+ years; living in the Netherlands | 619 (369 men, 350 women) | Cross-sectional study; single in-person session with each participant (baseline data from an intervention study) | 190-item FFQ | MMSE, Digit Span forward and backward, Trail Making Test, troop Color-Word Test, Letter Fluency, Symbol Digit Modalities Test, Rey Auditory Verbal Learning Test | Positive/no association | Fermented dairy consumption associated with increased executive function (β = 0.06, P = 0.03) Buttermilk consumption associated with increased executive function (β = 0.1, P = 0.03) Dutch cheese consumption reduced risk of low cognitive processing speed (HR = 0.67) No association between total yogurt or cheese consumption and any cognitive domain (P > 0.05 for β) |
de Goeij et al. (22) |
| 46–77 years old at end of study; living in the UK | 3,113 (1,634 men, 1,479 women) | Prospective study; diet and cognition were assessed at baseline, 5 years and 10 years | FFQ | Fluid Intelligence Test | Positive | Higher cheese intake associated with better test scores (β = 0.207, P < 0.0001) | Klinedinst et al. (39) |
| 55+ years; living in Spain | 6,426 (3,158, 3,288 women) | Cross-sectional study; single in-person session with each participant (baseline data from an intervention study) | 146 item FFQ | MMSE | Negative | High fermented dairy consumption increased odds of MMSE ≤ 26 (Q4 vs. Q1 AOR = 1.34, P = 0.003) | Muñoz-Garach et al. (26) |
| 65+ years; living in Canada | 7,945 (4,079 men, 3,866 women) | Cross-sectional study; single in-person session with each participant (baseline data from an intervention study) | 36-item short diet questionnaire | 15-word Rey Auditory Verbal Learning Test immediate and delayed recall, Mental Alternation Test, high interference of the Victoria Stroop test (interference/dot), event- and time-based prospective memory tests, and 2 verbal fluency tests, Animal Fluency Test and Controlled Oral Word Association Test of the letters, choice reaction time | Positive | Higher fermented dairy and cheese intakes associated with higher executive function scores (partial η2 = 0.002 and 0.001, P < 0.001) Higher yogurt intake associated with higher memory scores (partial η2 = 0.001, P < 0.05) |
Tessier et al. (27) |
| 42+ years at start of study; living in Finland | 1,741 men | Prospective study; diet was assessed and then cognition was measured 4 years later | 4-day food recording | Dementia diagnosis (1,259 participants); MMSE, trail making test A, verbal fluency test, selective reminding test, Russell's adaptation of the visual reproduction test (482 participants 60+ years) | Positive/no association | No association between fermented dairy intake and dementia risk (P = 0.26 for AOR) or cognitive performance scores (P > 0.05) Moderate cheese intake associated with lower dementia risk (AOR = 0.67, P = 0.05 for Q3 vs. Q1 intake) |
Ylilauri et al. (28) |
AOR, Adjusted odds ratio; FFQ, Food frequency questionnaire; HR, Hazard ratio; MMSE, Mini-Mental State Exam; Q1-Q4, Quintile 1–4 intake groups.
aCohen's d calculated based on data given in the publication.