Climate impact from diet in relation to background and sociodemographic characteristics in the Västerbotten Intervention Programme

Integrating environmental sustainability into food-based dietary guidelines in the Nordic countries

The overall aim of this paper was to provide background knowledge to the Nordic Nutrition Recommendations 2023 Committee for integrating environmental sustainability in a framework for national Food-Based Dietary Guidelines (FBDG) within the Nordics and Baltics. Additionally, this paper aims to give an overview of recent Nordic scientific literature on environmental impact of foods and dietary patterns and of the FBDG of the Nordics. Finally, we suggest methods for developing national sustainable FBDG. Nordic and Baltic studies on sustainability of diets were searched in August 2022 and complemented with additional relevant literature. The studies show that current diets are far from environmentally sustainable, exceeding planetary boundaries for most impact categories; meat and dairy products being the largest contributors to dietary greenhouse gas emissions (GHGEs) and land use. Scenario, modelling, optimisation and intervention studies confirm the potential of shifting towards more plant-based diets to improve overall diet quality in terms of both health and environmental sustainability. Such diets comprised of vegetables, fruits, legumes, potatoes, whole grain and refined cereal products, nuts, seeds and vegetable oils, with animal foods in moderate or limited amounts. The FBDG in the Nordics promotes more plant-based diets than the current average diet but could improve from further integration of environmental sustainability. To form basis for sustainable FBDG dietary modelling at the national level, prioritising health outcomes and nutritional adequacy is essential. Second, integrating environmental sustainability involves estimating the impact of food choices and amounts on GHGE, land and water use, eutrophication and biodiversity loss. Exploring positive and negative implications of fortified foods and supplementation in relation to nutrient intake, health and environmental sustainability may be needed. Implementing dietary transition requires solutions beyond FBDG to ensure affordability, acceptability and ease of adaption.

Dietary Greenhouse Gas Emissions and Diet Quality in a Cross-Sectional Study of Swedish Adolescents

BACKGROUND

Interventions to improve dietary intake and reduce dietary greenhouse gas emissions (dGHGE) are urgently needed. Adolescence presents a unique time in life to promote sustainable diets. Detailed dietary data are needed to inform public health strategies aiming at improving adolescents' diet quality and reducing dGHGE.

OBJECTIVE

This study aimed to describe dGHGE in Swedish adolescents' diets by socio-demographic characteristics, evaluate how food groups contribute to dGHGE, and examine dGHGE in relation to diet quality.

METHODS

Data come from the national, school-based, cross-sectional dietary survey Riksmaten Adolescents 2016-17 of 3099 females and males attending school grades 5 (11-12 y old), 8 (14-15 y old) and 11 (17-18 y old). Participants completed 2 web-based 24-h recalls and questionnaires on lifestyle factors. dGHGE was estimated based on life cycle assessment data. Diet quality was estimated using NRF11.3 (Nutrient Rich Food Index) and SHEIA15 (Swedish Healthy Eating Index for Adolescents 2015).

RESULTS

dGHGE were higher in males than females (medians 4.2 versus 3.8 kg CO2e/10 MJ, P < 0.001). In females, dGHGE were highest in grade 5 (4.0 kg CO2e/10MJ), whereas in males, emissions were highest in grade 11 (4.4 kg CO2e/10MJ), P < 0.001 for the sex/grade interaction. Overweight/obesity was positively associated with CO2e/10MJ, but parental education, birthplace, and degree of urbanization were not. In females, the proportion of dGHGE from animal-based foods was lowest in grade 11, whereas the proportions from plant-based foods and sweet foods/beverages were highest. In males, these proportions were similar across grades. NRF11.3 was not associated with CO2e/10MJ, whereas healthier eating, according to SHEIA15, was inversely associated with CO2e/10MJ.

CONCLUSIONS

Food choices and dGHGE per calorie differ by sex in adolescents. Thus, intervention strategies to improve dietary sustainability need to be tailored differently to females and males. Diet quality should also be considered when promoting reduced GHGE diets.

The effect of an app-based dietary intervention on diet-related greenhouse gas emissions - results from a randomized controlled trial

BACKGROUND

Dietary change towards a diet low in greenhouse gas emissions (GHGEs) can reduce climate impact and improve individual-level health. However, there is a lack of understanding if diet interventions can achieve low-GHGE diets.

METHODS

A randomized controlled trial was conducted to assess the effects of an app-based intervention. The intervention was designed to improve dietary intake of people with Type 2 diabetes, and was delivered via an app over 12 weeks, with each week covering one diet-related topic. Dietary intake was assessed at baseline and 3-month follow up by a 95-item food frequency questionnaire and linked to GHGE values. A total of n = 93 participants (n = 46 and n = 47 for the intervention and control group, respectively) were included in the analysis. Changes to GHGEs within and between the groups were analysed with inferential statistics.

RESULTS

The majority (60%) of participants were male, with a mean age of 63.2 years and body mass index of 30 kg/m2. At baseline, diet-related GHGEs were 4.8 and 4.9 kg CO2-eq/day in the intervention and control group, respectively. At 3-month follow up the corresponding GHGEs were 4.7 and 4.9 kg CO2-eq/day. We found no statistically significant changes to diet-related GHGEs within or between groups, or within food categories, from baseline to 3-month follow up.

CONCLUSION

No evidence was found for the effectiveness of the app-based intervention to generate changes to diet-related GHGEs in a population of people with Type 2 diabetes. However, future interventions that target reducing meat consumption specifically may have the potential to result in a reduction of individual-level diet-related GHGEs.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03784612. Registered 24 December 2018. www.

CLINICALTRIALS

gov/ct2/show/NCT03784612 .

The Chilean Diet: Is It Sustainable?

Food systems are one of the main contributors to climate change. Sustainable diets are one strategy to mitigate climate change. Assessments and estimations at a national level are lacking, especially in the Global South, probably due to a lack of national surveys of food consumption and a limited interest in sustainable diets information. The objective of this study is to estimate and describe the carbon and water footprint of the Chilean population’s diet in an overall estimation desegregated by region, age, sex, socioeconomic level and their main characterizations. This study is based on a secondary data analysis from the National Survey of Food Consumption made in 2010. The carbon and water footprint of the food subgroups/person/day were estimated. The results are compared by sex, age group, socioeconomic level, and macro zone. A carbon footprint of 4.67 kg CO_2eq and a water footprint of 4177 L, both per person/day, were obtained. Animal-sourced foods, such as dairy and red meat, were responsible for 60.5% of the total carbon footprint and 52.6% of the water footprint. The highest values for both footprints were found in the following groups: men, adolescents, young adults, people with a higher socioeconomic level, and residents in the southern area of the country. The carbon footprint and water footprint values in Chile generated by food consumption would be above the world averages. Transforming the Chilean food system into a more sustainable one with changes in eating patterns is urgently required to attain this transformation.

Carbon footprint of the Brazilian diet

OBJECTIVE

To estimate the carbon footprint of the Brazilian diet and of sociodemographic strata of this population.

METHODS

Carbon footprint of the diet was estimated based on data from two 24-hour diet records, obtained in 2008 and 2009, from a probabilistic sample of the Brazilian population aged 10 years and over (n = 34,003) and on environmental impact coefficients of food and culinary preparations consumed in Brazil (gCO2e/kg). Means with 95% confidence intervals of food consumption (kcal/person/day) and the carbon footprint of the diet (gCO2e/person/day and in gCO2e/2,000kcal) were calculated for the population as a whole and for strata according to sex, age, income, education, macro-regions and Federative Unit. Linear regression models were used to identify significant differences (p < 0.05) in the dietary carbon footprint of different sociodemographic strata.

RESULTS

The average carbon footprint of the Brazilian diet was 4,489gCO2e/person/day. It was higher for males, for the age group from 20 to 49 years and for the North and Midwest regions, and tended to increase with income and education. The pattern of association of footprint with sociodemographic variables did not change substantially with adjustment for differences in the amount of food consumed, except for a reduction in the relative excess of the footprint among males and an increase in the relative excess of the footprint in the Midwest region.

CONCLUSION

The carbon footprint of the Brazilian diet exceeds by about 30% the footprint of the human diet, which could simultaneously meet the nutritional requirements of a healthy diet and the global goal of containing the increase in the planet's average temperature. The pattern of association of this footprint with sociodemographic variables can help identify priority targets for public actions aimed at reducing the environmental impacts of food consumption in Brazil.

Secular trends in diet-related greenhouse gas emission estimates since 2000 - a shift towards sustainable diets in Sweden

Objective:

This study examines secular changes in diet-related greenhouse gas emissions (GHGE) in younger and older Swedish adults, since the turn of this century.

Design:

Two cross-sectional health examination surveys were conducted in 2001–2004 (T₁) and 2014–2018 (T₂). At both times, an eighty-six-item FFQ was embedded in the survey. From the food frequencies and age-standardised portion sizes, GHGE estimates (kg CO₂e/year) were calculated. GHGE was modelled as a function of time period and covariates, for five distinct age groups.

Setting:

The municipality of Gothenburg, in western Sweden.

Participants:

Women and men aged 25–34, 35–44, 45–54, 55–64 and 65–75 years were randomly selected from the population registry and recruited for examinations. After exclusion of participants with incomplete dietary data, the analytic sample consisted of 2569 individuals at T₁ and 2119 at T₂.

Results:

Lower dietary GHGE scores were observed at T₂ compared with T₁, in each age group, adjusting for sex, BMI and education. The largest differences in GHGE were observed in the youngest age group (approximately 30 % reduction). Decreasing trends in GHGE from animal-based foods were observed at all ages and were accompanied by smaller increases from plant-based sources in younger groups only. At all ages, GHGE from discretionary foods decreased, and prevalence of overweight remained stable.

Conclusions:

Optimal dietary trends should support both human health and planetary health. Our results suggest that Swedish adults have moved in this direction, e.g. through less intake of red meat products and stable weight status.

Diets benefiting health and climate relate to longevity in northern Sweden

BACKGROUND

Diets combining adequate nutritional quality and low climate impact are highly needed for human and planet health.

OBJECTIVES

We aimed to 1) evaluate nutrient density indexes' ability to predict mortality, and 2) assess the effects of diets varying in nutrient density and climate impact on total mortality.

METHODS

Dietary data from 49,124 women and 47,651 men aged 35-65 y in the population-based prospective study Västerbotten Intervention Programme (Sweden) were used. Greenhouse gas emissions (GHGEs) were estimated using data from life cycle assessments. Fifteen variants of nutrient density indexes were evaluated and the index that best predicted mortality was used to estimate participants' nutrient density. GHGEs and nutrient density were adjusted for energy intakes. Total mortality risk was estimated by Cox proportional hazards models for 4 groups of women and men, respectively, i.e., higher nutrient density, lower climate impact (HNutr/LClim); higher nutrient density, higher climate impact (HNutr/HClim); lower nutrient density, lower climate impact (LNutr/LClim); and lower nutrient density, higher climate impact (LNutr/HClim-reference group).

RESULTS

NRF11.3, a Sweden-adapted variant of the Nutrient Rich Foods index, was identified to have the best ability to predict mortality in the study population. Median follow-up times for women and men were 16.0 and 14.7 y, respectively. For women a significantly lower mortality risk was found for HNutr/LClim (HR: 0.87; 95% CI: 0.79, 0.96; P = 0.008) and HNutr/HClim (HR: 0.87; 95% CI: 0.78, 0.97; P = 0.011) than for LNutr/HClim. Among men LNutr/LClim had a significantly higher mortality risk (HR: 1.10; 95% CI: 1.01, 1.21; P = 0.033) than LNutr/HClim.

CONCLUSIONS

Diets beneficial for both health and climate are feasible and associated with lower mortality risk in women. Further studies are needed to understand how men may transition into diets that are more sustainable from a combined health and climate perspective.

Climate Change, Food Supply, and Dietary Guidelines

Food production is affected by climate change, and, in turn, food production is responsible for 20-30% of greenhouse gases. The food system must increase output as the population increases and must meet nutrition and health needs while simultaneously assisting in achieving the Sustainable Development Goals. Good nutrition is important for combatting infection, reducing child mortality, and controlling obesity and chronic disease throughout the life course. Dietary guidelines provide advice for a healthy diet, and the main principles are now well established and compatible with sustainable development. Climate change will have a significant effect on food supply; however, with political commitment and substantial investment, projected improvements will be sufficient to provide food for the healthy diets needed to achieve the Sustainable Development Goals. Some changes will need to be made to food production, nutrient content will need monitoring, and more equitable distribution is required to meet the dietary guidelines. Increased breastfeeding rates will improve infant and adult health while helping to reduce greenhouse gases.

Changes in dietary carbon footprint over ten years relative to individual characteristics and food intake in the Västerbotten Intervention Programme

The objective was to examine 10-year changes in dietary carbon footprint relative to individual characteristics and food intake in the unique longitudinal Västerbotten Intervention Programme, Sweden. Here, 14 591 women and 13 347 men had been followed over time. Food intake was assessed via multiple two study visits 1996–2016, using a 64-item food frequency questionnaire. Greenhouse gas emissions (GHGE) related to food intake, expressed as kg carbon dioxide equivalents/1000 kcal and day, were estimated. Participants were classified into GHGE quintiles within sex and 10-year age group strata at both visits. Women and men changing from lowest to highest GHGE quintile exhibited highest body mass index within their quintiles at first visit, and the largest increase in intake of meat, minced meat, chicken, fish and butter and the largest decrease in intake of potatoes, rice and pasta. Women and men changing from highest to lowest GHGE quintile exhibited basically lowest rates of university degree and marriage and highest rates of smoking within their quintiles at first visit. Among these, both sexes reported the largest decrease in intake of meat, minced meat and milk, and the largest increase in intake of snacks and, for women, sweets. More research is needed on how to motivate dietary modifications to reduce climate impact and support public health.