Moderate Consumption of Healthy Nordic Foods is Associated with Reduced Mortality in the Norwegian Women and Cancer Study: a Prospective Cohort Study

Abstract BackgroundHigh adherence to healthy Nordic diets may enhance longevity. However, optimal intake levels of healthy Nordic foods are not known. Hence, in a large prospective cohort of women in Norway we examined all-cause mortality in relation to intake of five food groups that are part of a healthy Nordic diet: Nordic fruits and vegetables, fatty fish, lean fish, wholegrain products, and low-fat dairy products. MethodsA total of 87 899 women who completed a food frequency questionnaire between 1996 and 2004 were followed for mortality until the end of 2018. Cox proportional hazards regression models were used to examine the associations between consumption of the Nordic food groups and all-cause mortality. The food groups were examined as categorical exposures, and all but wholegrain products also as continuous exposures in restricted cubic spline models.Results A total of 9 168 women died during the 20-year follow-up. Nordic fruits and vegetables, fatty fish and low-fat dairy products were not linearly associated with mortality (p < 0.05). The optimal intake levels and hazard ratios (HR) and 95% confidence intervals (CI) associated with these intakes were approximately 200 grams/day of Nordic fruits and vegetables (HR 0.84 (95% CI: 0.77–0.90)), 10–20 grams/day of fatty fish (HR 0.98 (95% CI: 0.92–1.03)) and 200 grams/day of low-fat dairy products (HR 0.94 (95% CI: 0.89–0.99)) compared to no consumption. High consumption of fatty fish (≥ 70 grams/day) was associated with increased mortality. Intake of wholegrain products of >120 grams/day was associated with lower mortality (HR 0.92 (95% CI: 0.85–0.99)) compared to < 60 grams per day. Lean fish consumption was not associated with mortality. After stratification by smoking status, the observed association for Nordic fruits and vegetables was only significant in ever smokers with the optimal intake level at 250 grams/day (HR 0.78 (95% CI: 0.71-0.86)).Conclusion Moderate intake of healthy Nordic foods seems to be better than low or high intake, and high consumption either does not add any beneficial effects or can compromise longevity. Stronger inverse associations for Nordic fruits and vegetables were observed in former and current smokers.