Every finding in the evidence table: 382 rows, filterable

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Area All 382 Care, carers and services 140 Medicines 85 Genes (not modifiable) 35 All modifiable factors together 27 Diet and supplements 23 Exercise and activity 21 Sleep, mood and social life 19 Hearing and vision 8 Alcohol, tobacco and cannabis 6 Infection and vaccination 5 Heart and metabolic health 4 Injury, delirium and falls 4 Environment 3 Cognitive activity 2

Question Both Prevention 190 Treatment 192

Direction Any Benefit 144 Harm 105 No effect 38 Mixed 37 No direction reported 58

Design Any meta-analysis 57 randomised trial 44 phase 3 trial 15 systematic review 9 phase 2 trial 10 cohort study 136 phase 1 trial 2 cross-sectional study 31 case-control study 14 modelling study 20 regulatory decision 7 company announcement 1 coverage determination 1 None 35

Showing 23 of 382 rows. One row per study per exposure: a study that tested two different things appears twice, once for each.

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Research and outcomes, 23 rows. Every row links to its source.
Exposure	Question	Direction	Outcome measured	Design	People	Effect size, as the source reported it	Source
Coffee, tea and flavonoid-rich foods Diet and supplements	Prevention	Benefit why The association was strongest at moderate intake rather than the highest.	Incident dementia over a median 36.8 years	cohort study	131,821	HR 0.82 (95% CI 0.76-0.89) for highest vs lowest quartile of caffeinated coffee	JAMA 2026 ✓ Peer-reviewed PMID 41661604
Coffee, tea and flavonoid-rich foods Diet and supplements	Prevention	Benefit why 882 cases across five quintiles and several interaction strata, so the subgroup estimates rest on small numbers.	Incident dementia over a mean 9.2 years	cohort study	121,986	AHR 0.72 (95% CI 0.57-0.89) for highest vs lowest flavodiet quintile	JAMA Network Open 2024 ✓ Peer-reviewed PMID 39292460
Dietary pattern (general) Diet and supplements	Prevention	Benefit why The association is reported in people who already have elevated Alzheimer's blood markers, which is the point of the study.	Incident dementia over a mean 8.4 years	cohort study	1,865	Dementia HR 0.71 (95% CI 0.58-0.88) per SD of anti-inflammatory diet adherence among participants with elevated p-tau217	JAMA Network Open 2026 ✓ Peer-reviewed PMID 42348207
Dietary pattern (general) Diet and supplements	Prevention	Benefit why Direction is for a healthier plant-based diet: higher overall and healthful plant-based diet scores were associated with lower dementia risk, while a higher unhealthful plant-based diet score was associated with higher risk (pooled HR 1.42).	Incident dementia by plant-based diet index (overall, healthful and unhealthful)	meta-analysis	207,981	higher scores in PDI and hPDI were associated with lower risk of dementia (highest vs. lowest tertile: pooled HR for PDI = 0.70, 95% CI, 0.53-0.92, p for trend <0.001; pooled HR for hPDI = 0.71, 0.48-1.06, p for trend = 0.03) ... higher uPDI was associated with higher dementia risk (highest vs. lowest tertile: pooled HR = 1.42, 1.19-1.70, p for trend <0.001). In the meta-analysis, individuals in the highest hPDI tertile had 21% lower dementia risk, and those in the highest uPDI tertile had 24% higher risk	The journal of prevention of Alzheimer's disease 2026 ✓ Peer-reviewed PMID 41564649
Dietary pattern (general) Diet and supplements	Prevention	Benefit why Independent of overall diet quality. Substituting olive oil for margarine or mayonnaise was also associated with lower risk; substituting for butter or other vegetable oils was not.	Dementia-related death over 28 years	cohort study	92,383	HR 0.72 (95% CI 0.64-0.81) for dementia-related death with ≥7 g/day olive oil vs never/rarely	JAMA Network Open 2024 ✓ Peer-reviewed PMID 38709531
Dietary pattern (general) Diet and supplements	Prevention	Benefit why Pooled observational studies only.	Dementia and Alzheimer's disease	meta-analysis	65,955	Pooled OR 0.89 (95% CI 0.84-0.94) for dementia; cohort HR 0.84 (0.76-0.94); Alzheimer's OR 0.73 (0.62-0.85)	Aging Clinical and Experimental Research 2024 ✓ Peer-reviewed PMID 38519775
Dietary pattern (general) Diet and supplements	Prevention	No effect why The control arm also received diet counselling and mild caloric restriction, so this is MIND against another active diet, not against usual eating. It is the only randomised test of the MIND diet here and it disagrees with the cohort evidence.	Global cognition at 3 years	randomised trial	604	Global cognition mean difference 0.035 standardised units (95% CI -0.022 to 0.092; P=0.23)	New England Journal of Medicine 2023 ✓ Peer-reviewed PMID 37466280
Dietary pattern (general) Diet and supplements	Prevention	Benefit why Observational. Points the opposite way to the randomised MIND diet trial.	Incident dementia	meta-analysis	224,049	HR 0.83 per 3-point MIND-score increment (95% CI 0.72-0.95); highest vs lowest tertile HR 0.83 (0.76-0.90)	JAMA Psychiatry 2023 ✓ Peer-reviewed PMID 37133875
Dietary pattern (general) Diet and supplements	Prevention	Benefit why Significant on one adherence score (MEDAS, HR 0.77) but not the other (PYRAMID, HR 0.86, 95% CI 0.73-1.02).	Incident dementia over a mean 9.1 years	cohort study	60,298	HR 0.77 (95% CI 0.65-0.91) for highest vs lowest MEDAS tertile	BMC Medicine 2023 ✓ Peer-reviewed PMID 36915130
Dietary pattern (general) Diet and supplements	Prevention	Benefit why Controls declined while the olive-oil arm held steady; the nut arm fell between the two. Cognitive follow-up was available for 334 of 447 enrolled.	Global cognition composite at median 4.1 years	randomised trial	447	Global cognition composite: +0.05 (95% CI -0.11 to 0.21) olive-oil arm vs -0.38 (-0.57 to -0.18) control; P=0.005	JAMA Internal Medicine 2015 ✓ Peer-reviewed PMID 25961184
Ginkgo biloba Diet and supplements	Treatment	Mixed why In dementia there may be small-to-moderate benefits at six months (low-certainty evidence, I2 88-96%); in MCI ginkgo probably has little or no effect (moderate certainty); in subjective cognitive complaints the effect is very uncertain. Adverse events were similar to placebo.	Global clinical status, cognition and activities of daily living at 6 months in dementia and in MCI; adverse events	meta-analysis	10,613	Dementia Thirteen studies (3288 participants) compared ginkgo with placebo for dementia. At six months, low-certainty evidence suggests that people taking ginkgo may have better global clinical status on a six-point Likert scale (lower is better; MD -0.06, 95% CI -1.00 to -0.20; I² = 88%; 5 studies, 1359 participants), better cognition measured by decreases on a short cognitive performance test (Syndrom-Kurztest; MD -1.86, 95% CI -3.48 to -0.24; I² = 96%; 9 studies, 2801 participants) ... Mild cognitive impairment ... moderate-certainty evidence suggests that ginkgo probably has little to no effect on global clinical status measured on the Clinical Dementia Rating Scale (MD -0.03, 95% CI -0.06 to 0.01; 3 studies, 631 participants; I² = 0%)	The Cochrane database of systematic reviews 2026 ✓ Peer-reviewed PMID 41641880
MIND diet Diet and supplements	Prevention	No effect why The control arm also received diet counselling and mild caloric restriction, so this is MIND against another active diet, not against usual eating. It is the only randomised test of the MIND diet here and it disagrees with the cohort evidence.	Global cognition at 3 years	randomised trial	604	Global cognition mean difference 0.035 standardised units (95% CI -0.022 to 0.092; P=0.23)	New England Journal of Medicine 2023 ✓ Peer-reviewed PMID 37466280
MIND diet Diet and supplements	Prevention	Benefit why Observational. Points the opposite way to the randomised MIND diet trial.	Incident dementia	meta-analysis	224,049	HR 0.83 per 3-point MIND-score increment (95% CI 0.72-0.95); highest vs lowest tertile HR 0.83 (0.76-0.90)	JAMA Psychiatry 2023 ✓ Peer-reviewed PMID 37133875
Mediterranean diet Diet and supplements	Prevention	Benefit why Pooled observational studies only.	Dementia and Alzheimer's disease	meta-analysis	65,955	Pooled OR 0.89 (95% CI 0.84-0.94) for dementia; cohort HR 0.84 (0.76-0.94); Alzheimer's OR 0.73 (0.62-0.85)	Aging Clinical and Experimental Research 2024 ✓ Peer-reviewed PMID 38519775
Mediterranean diet Diet and supplements	Prevention	Benefit why Significant on one adherence score (MEDAS, HR 0.77) but not the other (PYRAMID, HR 0.86, 95% CI 0.73-1.02).	Incident dementia over a mean 9.1 years	cohort study	60,298	HR 0.77 (95% CI 0.65-0.91) for highest vs lowest MEDAS tertile	BMC Medicine 2023 ✓ Peer-reviewed PMID 36915130
Mediterranean diet Diet and supplements	Prevention	Benefit why Controls declined while the olive-oil arm held steady; the nut arm fell between the two. Cognitive follow-up was available for 334 of 447 enrolled.	Global cognition composite at median 4.1 years	randomised trial	447	Global cognition composite: +0.05 (95% CI -0.11 to 0.21) olive-oil arm vs -0.38 (-0.57 to -0.18) control; P=0.005	JAMA Internal Medicine 2015 ✓ Peer-reviewed PMID 25961184
Omega-3 / fish and fish oil Diet and supplements	Prevention	No effect why Risk ratios close to one across every intake strategy, including substituting fish for meat. This is the one study here that emulates a trial rather than comparing eaters with non-eaters, and it disagrees with the pooled cohorts.	21-year Alzheimer's disease risk	cohort study	2,012	21-year Alzheimer's risk 10.33% (no fish) vs 9.98% (3+ servings/week); risk ratios near 1	American Journal of Epidemiology 2026 ✓ Peer-reviewed PMID 42506897
Omega-3 / fish and fish oil Diet and supplements	Prevention	Mixed why The biochemical primary outcome was met (DHA raised the CSF DHA-to-arachidonic-acid ratio versus placebo), but there was no difference in cognition or brain volume over 24 months. The authors recommend against further supplementation trials of this kind.	CSF DHA/AA ratio at 6 months (primary, target engagement); cognition and brain volumes at 24 months	phase 2 trial	365	DHA supplementation increased CSF DHA/AA ratio at 6 months vs placebo (0.17 [95% CI 0.15-0.18] vs -0.02 [95% CI -0.04 to -0.0004]; difference 0.19 [95% CI 0.16-0.21]; p < 0.0001), independent of APOE ε4 status (interaction p = 0.71). Dropout was 38%, mainly due to COVID-19. No treatment differences were observed in brain volumes or cognitive performance over 24 months	EBioMedicine 2026 ✓ Peer-reviewed PMID 42315445
Omega-3 / fish and fish oil Diet and supplements	Prevention	Benefit why Dietary intake and blood levels, pooled from observational cohorts. The much larger supplement estimate (HR 0.36) comes from one cohort's self-selected supplement users, not from a trial.	All-cause dementia or cognitive decline	meta-analysis	103,651	Dietary DHA intake RR 0.82 for dementia or cognitive decline; ADNI supplement users HR 0.36 (95% CI 0.18-0.72) for Alzheimer's	American Journal of Clinical Nutrition 2023 ✓ Peer-reviewed PMID 37028557
Ultra-processed food Diet and supplements	Prevention	Harm why The dementia-only estimate barely cleared significance (HR 1.58, 95% CI 1.003-2.48) and its test for trend did not (P=0.50).	Cognitive impairment or dementia	cohort study	5,370	Cognitive impairment or dementia HR 1.47 (95% CI 1.16-1.87) for highest vs lowest quintile of ultra-processed food	American Journal of Public Health 2026 ✓ Peer-reviewed PMID 42233196
Ultra-processed food Diet and supplements	Prevention	Harm why Heterogeneity was extreme (I-squared 97%), so the pooled figure hides large differences between the 10 studies.	Dementia	meta-analysis	867,316	Pooled RR 1.44 (95% CI 1.09-1.90) for high vs low ultra-processed food intake	Journal of Neurology 2024 ✓ Peer-reviewed PMID 37831127
Ultra-processed food Diet and supplements	Prevention	Harm	Rate of global cognitive decline over a median 8 years	cohort study	10,775	28% faster global cognitive decline above the lowest quartile (beta -0.004; 95% CI -0.006 to -0.001)	JAMA Neurology 2023 ✓ Peer-reviewed PMID 36469335
Ultra-processed food Diet and supplements	Prevention	Harm why 518 cases. Replacing 10% of ultra-processed food with minimally processed food was associated with 19% lower risk.	Incident dementia over a median 10 years	cohort study	72,083	HR 1.25 per 10% increase in ultra-processed food share (95% CI 1.14-1.37)	Neurology 2022 ✓ Peer-reviewed PMID 36219796

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