Swedish dietary guidelines linked to longer life and lower emissions

Introduction

The study, based on a large Swedish cohort (n = 96,775), examined the link between adherence to Swedish dietary guidelines (measured by the SHEIA15 diet quality index) and mortality risk and dietary greenhouse gas (GHG) emissions.(1)

Study design

Data was collected from the Västerbotten Intervention Programme (VIP). Between 1990-2016 the VIP recruited 49,124 women and 47,651 men aged 35-65.

Diet quality assessment

The participants’ food intake was reported using a semi-quantitative food frequency questionnaire (FFQ) during a yearly baseline visit.

Diet quality was assessed using SHEIA15 (Swedish Healthy Eating Index for Adults 2015) score which includes 9 components:

• 6 positive components (vegetables and fruit, seafood, whole grains, dietary fiber, mono and polyunsaturated fatty acids)

• 3 negative components (saturated fatty acids, red and processed meat, and added sugar)

SHEIA15 score ranges from 0 to 9 with 9 indicating highest adherence to the Swedish FBDG and 0 indicating little to no adherence.

Based on their SHEIA15 scores, the participants were separated into quintiles, with quintile 1 having the lowest SHEIA score, and quintile 5 having the highest score meaning a high adherence to the FBDG.

Mortality & dietary GHG emissions assessment

Dietary GHG emissions were estimated using life cycle assessment data from the Research Institutes of Sweden Food and Climate Database.

All-cause mortality data was obtained by linking the VIP participants to the “cause of death” registers at the National Board of Health and Welfare in Sweden.

Hazard ratios for all-cause mortality between quintiles were adjusted for potential confounders including age, educational level , BMI, smoking status, physical activity and education level.

Results

During the time of the study (1990–2016), the median follow-up time was 16 years for women and 14,7 years for men, during which 3,074 women and 4,212 men died.

SHEIA15 score and all-cause mortality

Compared with quintile 1 (lowest adherence to the Swedish FBDG), quintiles 2 to 5 all showed statistically significant lower all-cause mortality hazard ratios for both women and men. Thus, a higher SHEIA15 score and therefore greater adherence to the Swedish FBDG was associated with a decrease in all-cause mortality.

SHEIA15 score and GHG emissions

Similarly, an increasing SHEIA15 score was associated with significantly lower dietary GHG emissions for both men and women. Interestingly, there was no significant difference in median GHG emissions between quintile 1 and 5 when excluding the red and processed meat component from the SHEIA15 score.

This result suggested that the association between SHEIA15 score and GHG emissions is dependent on the red and processed meat component of the diet and further highlights the need to decrease its consumption to reduce dietary GHG emissions.

Conclusion

Higher adherence to the Swedish FBDG assessed by the SHEIA15 score is associated with living longer in good health and lower dietary GHG emissions amongst a Swedish population, suggesting that the SHEIA15 score can efficiently be used to predict dietary health and environmental outcomes.

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