How do you like them apples?
https://x.com/robertlufkinmd/status/2036399359495930268?s=46&t=4EadOlXmhNuHXx8rV1pc9g
I glanced at the paper. @DrFraser ?
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Interesting paper … but having a Mediterranean diet has more robust and varied sources supporting it, and consumption of meat results in multiple other bad health outcomes. I think the PRO-21 diet from Dr. Mischley is probably not only valid for PD but also AD … and read meat is among many items that results in faster neurodegeneration (others are really interesting like canned fruit, frozen vegetables).
I would be much more interested if this paper also controlled for methylmalonic acid and omega 3 index. I suspect those confounders would explain away the benefit. Those are items I monitor and optimize in my patients. These 2 factors likely explain excess late neurodegeneration in vegans.
I’ll go with Vera Health’s review of this topic.
But quite importantly as I remind my ApoE4 patients, the incredible focus on ApoE4 and neurodegeneraton only matters if you live long enough to get dementia. So doing things that increase heart disease and cancer risk and not optimizing all those things and unifocal view of just your ApoE4 is a bad strategy.
Higher meat consumption does not consistently decrease Alzheimer’s disease or dementia incidence; the most reproducible signal across large cohorts is higher risk with processed meat, while unprocessed red meat shows mixed (sometimes inverse) associations, and any apparent benefit may be genotype- and meat-type–specific rather than a general protective effect.
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Processed meat: generally associated with higher incident dementia/AD risk (most clinically actionable finding).
- UK Biobank cohort (493,888 participants; 2,896 all-cause dementia; mean follow-up 8 ± 1.1 years): each 25 g/day processed meat increment associated with higher risk of all-cause dementia (HR 1.44) and AD (HR 1.52) 1. (Large prospective cohort; robust effect sizes; APOE ε4 did not materially modify associations.)
- NHS/HPFS pooled cohorts (133,771 participants): processed red meat ≥0.25 serving/day vs <0.10 serving/day associated with 13% higher dementia risk (HR 1.13; 95% CI 1.08–1.19) 2. (Large prospective cohorts with long diet follow-up; dementia ascertainment across decades.)
- Dose-response meta-analysis of 24 prospective cohorts (>500,000 participants): processed meat associated with higher neurodegenerative cognitive impairment risk (e.g., total processed meat RR 1.67) and per 50 g/day processed meat increment RR 1.12 3. (Broad synthesis; still observational/heterogeneous outcomes.)
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Unprocessed red meat / “total meat”: inconsistent, not a reliable protective exposure.
- UK Biobank: 50 g/day unprocessed red meat increment associated with lower all-cause dementia (HR 0.81) and AD (HR 0.70) 1. (Prospective, but contrasts with other evidence and may reflect residual confounding/substitution effects.)
- Meta-analysis of prospective cohorts: total meat intake associated with higher neurodegenerative cognitive impairment risk (RR 1.14) while red meat itself was null (RR 1.03; 95% CI 0.92–1.16) 3. (Suggests “total meat” effect may be driven by processing/overall dietary pattern rather than unprocessed red meat.)
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Possible APOE-specific association (hypothesis-generating; not practice-changing).
- SNAC-K Swedish cohort (2,157 dementia-free at baseline; 15 years follow-up; 296 incident dementia): among APOE ε3/ε4 or ε4/ε4 (569 participants), top vs bottom quintile total meat associated with lower dementia risk (sHR 0.45; P=0.04), with no association in other genotypes (sHR 0.95) 4. (Well-done cohort with competing-risk modeling; but single cohort, subgroup finding; processed-to-total meat ratio associated unfavorably with dementia sHR 1.14) 4.
Clinical interpretation: if counseling on dementia prevention from this evidence base, prioritize limiting processed meat rather than increasing overall meat intake; any “protective” association for higher meat intake appears non-generalizable and may depend on meat processing and possibly APOE genotype rather than meat quantity per se.
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I agree for the reasons you list also also the design that produced the headline findings. This study is definitely interesting but a very long way from determinative. In contrast, the sheer volume and degree of consensus on Mediterranean style eating is determinative.
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As the title suggests, the findings are for a specific cohort, not the general population.
Study Population
The Swedish National Study on Aging and Care–Kungsholmen (SNAC-K) is an ongoing, longitudinal, population-based study targeting individuals aged 60 years or older in an urban area of Stockholm.22 In the first wave (2001-2004), 3363 of 5111 randomly selected individuals were enrolled; 2157 participants met the inclusion criteria for this analysis: baseline data on diet, cognition, and APOE status and no dementia at baseline.
Nordic, 60+, urban area dwellers.
Conclusions
In this cohort study, we found that the APOE34/44 group exhibited the anticipated excess risk of cognitive decline and dementia progression compared with participants with other genotypes when consuming meat at levels consistent with current dietary guideline targets. However, this disadvantageous association was absent at higher consumption levels, equivalent to more than twice the target.33 Viewed alongside reinterpreted evidence from NHS37 and UK Biobank21 focusing on unprocessed meat, these findings point to a consistent gene-diet interaction, with important implications for public health. Results reinforce the urgency of investing in precision nutrition research with a focus on APOE, which could ultimately inform future policy development.
However, our findings align with underappreciated patterns in 2 large cohorts. In the UK Biobank (493 888 participants), unprocessed red meat was inversely associated with dementia (P = .01), driven by APOE4 carriers (HR, 0.64 per 50-g/d increase; P < .001), with no associations in noncarriers (HR, 0.93; P = .59).21 In the Nurses’ Health Study (NHS) and Health Professionals Follow-up Study (133 771 participants), supplementary analyses revealed an APOE4 interaction (P < .001) for unprocessed red meat, showing favorable trends among carriers and adverse trends among noncarriers.
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2846712
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I kinda fit that cohort-ish. 
Midwest dirt, beef meat, tators and whole milk.
One supporting perspective is the lower prevalence of APOE4 , suggesting adverse selection, in agricultural regions.15 In Europe, APOE4 allele frequency decreases gradually from up to 27% in the north to as low as 4% in the south.