A long-term analysis of Swedish health data found a split result for the healthy Nordic diet: the model estimated a meaningful reduction in deaths from all causes, but it did not show clear protection from severe liver disease.
Researchers led by Michael Fridén at Aarhus University used records from 64,406 adults in two Swedish population cohorts to estimate what might have happened if participants had followed a healthy Nordic diet over 24 years. The open-access study appears in The American Journal of Clinical Nutrition.
Modeling an experiment that could not run for decades
The researchers used dietary measurements collected in 1997, 2008 or 2009, and 2019. They applied a statistical method called the parametric g-formula to emulate a hypothetical trial, comparing a healthy Nordic diet, the Nordic Nutrition Recommendations 2023 and no dietary intervention.
This approach can estimate long-term outcomes when assigning thousands of people to strict diets for decades would be impractical. It is not the same as a randomized clinical trial, however. The authors said their estimates depend on strong assumptions that there was no unmeasured confounding, selection bias or measurement error.
Medical Xpress describes the healthy Nordic pattern as emphasizing foods common to Nordic countries, including plant foods and berries, whole grains, low-fat dairy and fatty fish.
Mortality and liver results point in different directions
Compared with no intervention, the healthy Nordic diet was associated with an estimated 2.67-percentage-point reduction in the 24-year risk of death from any cause. The 95% confidence interval ranged from a reduction of 1.85 to 3.51 percentage points. Compared with the Nordic Nutrition Recommendations diet, the estimated reduction was 1.68 percentage points.
The liver findings were less conclusive. The model estimated a 24-year risk of major adverse liver outcomes of 0.53% for the healthy Nordic diet, 0.70% for the Nordic Nutrition Recommendations diet and 0.64% without an intervention. But the healthy Nordic diet's difference from no intervention was only 0.11 percentage points, and its confidence interval crossed zero. That means the analysis did not establish a clear reduction in outcomes such as cirrhosis or liver cancer.
The study therefore supports a narrower conclusion than a simple "Nordic diet extends life" claim. Its model found a lower all-cause mortality risk under the healthy Nordic pattern, while the severe liver-disease result remained uncertain. Testing the approach in other populations could show whether the estimates hold beyond these middle-aged and older Swedish cohorts.
