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 8 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, 8 rows. Every row links to its source.
Exposure	Question	Direction	Outcome measured	Design	People	Effect size, as the source reported it	Source
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 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	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
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	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
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 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

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