Abstract
Objectives To assess the health impacts and environmental consequences of adherence to national dietary recommendations (the Eatwell Guide (EWG)) in the UK. Design and setting A secondary analysis of multiple observational studies in the UK. Participants Adults from the European Prospective Investigation into Cancer – Oxford(EPIC-Oxford), UK Biobank and Million Women Study, and adults and children aged 5 and over from the National Diet and Nutrition Survey (NDNS). Primary and secondary outcome measures risk of total mortality from Cox proportional hazards regression models, total greenhouse gas emissions (GHGe) and blue water footprint (WF) associated with ‘very low’ (0–2 recommendations), ‘low’ (3–4 recommendations) or ‘intermediate-to-high’ (5–9 recommendations) adherence to EWG recommendations. Results Less than 0.1% of the NDNS sample adhere to all nine EWG recommendations and 30.6% adhere to at least five recommendations. Compared with ‘very low’ adherence to EWG recommendations, ‘intermediate-to-high adherence’ was associated with a reduced risk of mortality (risk ratio (RR): 0.93; 99% CI: 0.90 to 0.97) and -1.6kg CO2eq/day (95% CI: −1.5 to −1.8), or 30% lower dietary GHGe. Dietary WFs were similar across EWG adherence groups. Of the individual Eatwell guidelines, adherence to the recommendation on fruit and vegetable consumption was associated with the largest reduction in total mortality risk: an RR of 0.90 (99% CI: 0.88 to 0.93). Increased adherence to the recommendation on red and processed meat consumption was associated with the largest decrease in environmental footprints (-1.48 kg CO2eq/day, 95% CI: −1.79 to 1.18 for GHGe and -22.5L/day, 95% CI: -22.7 to 22.3 for blue WF). Conclusions The health and environmental benefits of greater adherence to EWG recommendations support increased government efforts to encourage improved diets in the UK that are essential for the health of people and the planet in the Anthropocene.
Generated Summary
This study, published in BMJ Open, investigates the health impacts and environmental consequences of adherence to the Eatwell Guide (EWG) in the UK. It employs a secondary analysis of multiple observational studies, including data from EPIC-Oxford, UK Biobank, Million Women Study, and the National Diet and Nutrition Survey (NDNS). The research examines the association between varying levels of adherence to EWG recommendations and health outcomes, specifically total mortality risk, and environmental footprints, including greenhouse gas emissions (GHGe) and blue water footprint (WF). The study categorizes adherence levels as ‘very low,’ ‘low,’ and ‘intermediate-to-high’ based on the number of EWG recommendations met. The methodologies involve the use of Cox proportional hazards regression models to assess mortality risk and the calculation of GHGe and WF associated with different dietary patterns. The study aims to provide evidence supporting government efforts to encourage improved diets in the UK, thereby benefiting both human health and the environment.
Key Findings & Statistics
- Adherence to EWG Recommendations: Less than 0.1% of the NDNS sample adhered to all nine EWG recommendations, while 30.6% adhered to at least five recommendations.
- Mortality Risk: Compared to ‘very low’ adherence to EWG recommendations, ‘intermediate-to-high’ adherence was associated with a reduced risk of mortality (risk ratio (RR): 0.93; 99% CI: 0.90 to 0.97).
- Greenhouse Gas Emissions (GHGe): ‘Intermediate-to-high’ adherence was linked to a -1.6kg CO₂eq/day (95% CI: −1.5 to −1.8) reduction in GHGe, which is 30% lower dietary GHGe.
- Water Footprint (WF): Dietary WFs were similar across EWG adherence groups.
- Fruit and Vegetable Consumption: Adherence to the recommendation on fruit and vegetable consumption was associated with the largest reduction in total mortality risk: an RR of 0.90 (99% CI: 0.88 to 0.93).
- Red and Processed Meat Consumption: Increased adherence to the recommendation on red and processed meat consumption was associated with the largest decrease in environmental footprints (-1.48 kg CO2eq/day, 95% CI: −1.79 to 1.18 for GHGe and -22.5L/day, 95% CI: -22.7 to 22.3 for blue WF).
- Million Women Study: In the MWS, the 0-2 recommendation group had a mortality risk ratio of 1.00, 3-4 recommendations had 0.96 (0.93, 0.99), and 5+ recommendations had 0.93 (0.90, 0.97).
- UK Biobank: In the UK Biobank, the 0-2 recommendation group had a mortality risk ratio of 1.00, 3-4 recommendations had 0.94 (0.70, 1.26), and 5+ recommendations had 0.69 (0.47, 1.03).
- EPIC Oxford: In EPIC Oxford, the 0-2 recommendation group had a mortality risk ratio of 1.00, 3-4 recommendations had 0.98 (0.87, 1.10), and 5+ recommendations had 0.95 (0.84, 1.08).
- Mean GHGe and WFs: Average daily GHGe in kg CO₂eq/day for very low (score 0-2) was 5.6kg CO₂eq/day (95% CI: 5.2 to 5.6kg CO₂eq/day), low (score 3-4) was 4.3kg CO₂eq/day (95% CI: 4.1 to 4.4kg CO₂eq/day), and intermediate-to-high (score 5-9) was 3.9kg CO₂eq/day. Dietary blue WFs were similar across adherence groups.
- Mean Differences in Consumption: Mean difference in consumption of foods between EWG adherent and non-adherent individuals was large. The red and processed meat recommendation showed a lower blue WF (-22.5 L/person/day; 95% CI: -22.7 to -22.3).
Other Important Findings
- The study highlights that the health and environmental benefits of greater adherence to EWG recommendations support increased government efforts to encourage improved diets in the UK.
- The research emphasizes that adherence to the fruit and vegetable recommendation was associated with the largest reduction in total mortality risk.
- Adherence to the red and processed meat recommendation was linked to the most significant decrease in environmental footprints.
- Compared to very low adherence, intermediate-to-high adherence was associated with a reduced risk of mortality.
- The study confirms that the EWG recommendations are associated with lower environmental footprints in terms of GHGe.
Limitations Noted in the Document
- The study acknowledges potential residual confounding due to unmeasured differences between individuals who eat different diets.
- Uncertainty exists regarding the exact measurements of water footprints and greenhouse gas emissions of food items and diets in general.
- The simplification that all diets that met a certain number of recommendations were equally healthy, regardless of which recommendations were met, is a limitation.
- The assumption that lower consumption of one food group or nutrient could not be compensated by higher consumption of other foods is another limitation.
- Low interindividual variance in diets associated with high adherence to some recommendations combined with relatively low overall intake may have resulted in low power to detect diet-health associations.
- As with all studies measuring dietary intake, assessment is subject to measurement error.
- It was not possible to assess both health and environmental footprints of diets within single datasets.
Conclusion
The findings of this study underscore the importance of adopting the Eatwell Guide (EWG) dietary recommendations to improve both public health and environmental sustainability in the UK. The research demonstrates that greater adherence to the EWG is associated with reduced mortality risk and lower greenhouse gas emissions, highlighting the potential for significant benefits from increased adherence to the guidelines. The study’s results support the need for governmental efforts to promote improved diets within the UK, recognizing the interconnectedness of individual health and planetary well-being. Key insights include the largest reduction in total mortality risk associated with fruit and vegetable consumption, and the significant decrease in environmental footprints related to reduced consumption of red and processed meat. However, the study also notes the need for careful consideration of the limitations, such as potential confounding factors and uncertainties in environmental footprint measurements. The authors emphasize that while the EWG provides a positive step, further improvements in sustainability may require additional changes. The study’s findings support the promotion of the EWG recommendations to their patients and thereby contribute directly to population health and environmental sustainability.