Across two Swedish population-based cohorts totalling 64,406 middle-aged and older adults, adherence to a Healthy Nordic Diet (HND) — emphasising whole grains, fatty fish, berries, and root vegetables — was associated with an estimated 2.67 percentage-point reduction in 24-year all-cause mortality risk (95% CI: −3.51 to −1.85) versus no dietary change. The Nordic Nutrition Recommendations 2023 yielded a smaller but significant −1.68 pp reduction. For major adverse liver outcomes (MALO), however, neither dietary pattern achieved statistically credible risk reductions, with confidence intervals crossing zero for both.
The all-cause mortality signal is meaningful and consistent with Mediterranean and DASH diet literature showing Nordic-style diets can rival the Mediterranean pattern in Northern European populations. The null liver finding is surprising given short-term trials demonstrating HND reduces hepatic fat, but translating surrogate markers to hard clinical endpoints like cirrhosis or liver failure over decades is notoriously difficult — especially at population-level absolute risks this low (under 1%).
Methodologically, this target trial emulation using the parametric g-formula is more rigorous than standard observational regression, but hinges on the heroic assumption of no unmeasured confounding — a limitation the authors explicitly flag. Repeated dietary measurements across three time points (1997, 2008/2009, 2019) strengthen exposure characterisation. Overall, the mortality finding is confirmatory and clinically actionable; the liver null result is underpowered by low event rates rather than absence of effect.