Table 4.
Summary of observational studies assessing dairy lipid intake and cognitive function.
| Participants | Numbers | Design | Diet measures | Cognitive tests | Outcome | Results | Reference |
|---|---|---|---|---|---|---|---|
| 65–79 years at end of study; from Finland | 1,341 (596 men, 835 women) | Prospective study; diet was assessed and then cognition was measured 10–25 years later | 20-item FFQ | MMSE, dementia/AD diagnosis | Positive/negative | Likelihood of developing dementia was reduced in those who consumed moderate dairy lipids (Q2 vs. Q1 AOR = 0.43, P < 0.05) Moderate intake of dairy PUFA and MUFA had protective effects (Q2 and Q3 vs. Q1 AOR = 0.48 and 0.51 for dementia; Q3 vs. Q1 AOR = 0.36 for AD, P < 0.05) Moderate intake of dairy SFA increased risk of dementia and AD (Q2 vs. Q1 AOR = 1.76 for dementia; Q3 vs. Q1 AOR = 2.29 for AD, P < 0.05) |
Laitinen et al. (35) |
| 65–79 years at end of study; from Finland | 1,341 (596 men, 835 women) | Prospective study; diet was assessed and then cognition was measured 10–25 years later | 20-item FFQ | MMSE, word recall tests, The Category Fluency Test, Purdue Peg Board task, letter digit substitute test, Stroop test | Negative | High dairy lipid and SFA consumption in mid-life associated with MCI (AOR = 1.69 and 2.36 adjusted for MCI risk factors) High dairy lipid intake group had lower MMSE and psychomotor speed scores (Cohen's d = 0.12 and 0.33a) High SFA intake group had lower MMSE and prospective memory scores (Cohen's d = 0.15 and 0.05a) |
Eskelinen et al. (36) |
| 76–82 years at end of study; from France | 4,809 women | Prospective study; diet was assessed and then cognition was measured 13 years later | 208-item diet history questionnaire | “DEte'rioration Cognitive Observe'e” (DECO, observed cognitive deterioration) score; IADL | Negative | High intake of dairy desserts and ice cream associated with higher risk of cognitive decline compared to no intake (AOR = 1.33 for observed cognitive deterioration score) | Vercambre et al. (37) |
| 60+ years; living in Brazil | 400 (112 men, 288 women) | Cross-sectional study; single in-person session with each participant | Weekly consumption estimates | MMSE | No association | No difference in risk of cognitive deficit in those who consumed whole vs. skim milk (P = 0.998 for AOR) | Franca et al. (38) |
| 60+ years; living in the Netherlands | 619 (369 men, 350 women) | Cross-sectional study; single in-person session with each participant (baseline data from 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 | No association | Association between skim dairy intake and executive function (β = 0.07, P = 0.01), but not full-fat dairy (P > 0.05) No association between full-fat or semi-skim/skim milk consumption and any of the cognitive domains tested (P > 0.05 for β) |
de Goeij et al. (22) |
| 55+ years; living in Spain | 6,426 (3,158, 3,288 women) | Cross-sectional study; single in-person session with each participant (baseline data for longitudinal study) | 146 item FFQ | MMSE | Positive | Moderate full-fat milk and dairy consumption decreased odds of MMSE ≤ 26 (Q2 vs. Q1 AOR = 0.73, P = 0.001; Q3 vs. Q1 AOR = 10.74, 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 for longitudinal 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 | No association | No association between full-fat dairy intake and cognitive test scores in adjusted models (P > 0.05 for all partial η2) | Tessier et al. (27) |
AOR, Adjusted odds ratio; FFQ, Food frequency questionnaire; HR, Hazard ratio; IADL, Instrumental activities of daily living; MMSE, Mini-Mental State Exam; MUFA, Monounsaturated fatty acids; PUFA, Polyunsaturated fatty acids; SFA, Saturated fatty acids; Q1-Q4, Quintile 1–4 intake groups.
aCohen's d calculated based on data given in the publication.