Healthy diet: a step toward a sustainable diet by reducing water footprint

Can micronutrient requirements be met by diets from sustainable sources: outcomes of dietary modelling studies using diet optimization

BACKGROUND

Consumption of diets from sustainable sources is required for planetary health, however, large sections of the population, including females of reproductive age and children, will be at risk of not meeting their micronutrient (MN) requirements in a complete transition to plant-based foods. Constrained diet optimization methods use mathematical programming to construct diets that meet predefined parameters and may contribute towards modelling dietary solutions that meet nutritional and planetary targets.

OBJECTIVE

Review the evidence from diet optimization studies proposing solutions to ensure MN availability in the context of a transition to diets from sustainable sources.

APPROACH

Narrative review focusing on literature published over the last five years.

RESULTS

Dietary modelling using diet optimization can design a range of omnivorous and plant-based diets that meet individual MN requirements, have reduced environmental impacts, and minimize deviation from culturally acceptable dietary practices. Using data from large-scale dietary surveys, diet optimization can support development of food-based dietary guidelines; identify limiting MNs in a particular context or a conflict between constraints e.g. nutrition and environment; explore food-based strategies to increase nutrient supply, such as fortification; and support trial design. Methods used and outcomes reported are sources of variability. Individual-level dietary data and MN requirements for population sub-groups such as females of reproductive age and children are important requirements. Although maintaining iron and zinc intakes are regularly reported to present challenges in diets from sustainable sources, few studies have considered bioavailability, which reduces with increased dietary phytate. These and other data gaps including acceptability and affordability must be addressed to improve the applicability of modelling outcomes in population recommendations.

CONCLUSIONS

Dietary modelling using diet optimization can be useful in the design of more sustainable diets that meet MN requirements, however, translation of outcomes into dietary intervention studies is required to test real-world application and adoption into dietary guidelines.

Adherence to the planetary health diet index and metabolic syndrome: cross-sectional results from the PERSIAN cohort study

BACKGROUND/OBJECTIVES

The Planetary Health Diet Index (PHDI) was recently introduced to assess adherence to the EAT-Lance recommendations. In this study, we aimed to evaluate the relationship between PHDI and metabolic syndrome (MS).

SUBJECTS/METHODS

We used the data of 6465 participants from the PERSIAN cohort study at Mashhad University of Medical Sciences, Mashhad, Iran. Diet was assessed using a 130-item Food Frequency Questionnaire (FFQ). The PHDI comprises sixteen components and is scored between 0 and 150 points. We first assessed the validity and reliability of the PHDI for this population. We used regression logistic models to assess the relationships between PHDI and MS and its related indicators.

RESULTS

The average PHDI score was 52.3 ± 9. The Cronbach's alpha value was 0.53. After controlling for age and sex, the PHDI was positively related to the Diet Quality Index-International (DQI-I) and was negatively related to carbon and water footprints (p < 0.001). PHDI quartile was negatively associated with MS, hypo-HDL cholesterolemia, and abdominal obesity after controlling for confounders (P < 0.05).

CONCLUSION

The validity and reliability of the PHDI were found to be satisfactory for the Iranian population we studied. Our results showed that a higher PHDI was potentially related to a reduced likelihood of MS, hypo-HDL cholesterolemia, and abdominal obesity.

Impact of consuming an environmentally protective diet on micronutrients: a systematic literature review

BACKGROUND

A global move toward consumption of diets from sustainable sources is required to protect planetary health. As this dietary transition will result in greater reliance on plant-based protein sources, the impact on micronutrient (MN) intakes and status is unknown.

OBJECTIVE

Evaluate the evidence of effects on intakes and status of selected MNs resulting from changes in dietary intakes to reduce environmental impact. Selected MNs of public health concern were vitamins A, D, and B12, folate, calcium, iron, iodine, and zinc.

METHODS

We systematically searched 7 databases from January 2011 to October 2022 and followed the PRISMA guidelines. Eligible studies had to report individual MN intake and/or status data collected in free-living individuals from the year 2000 onward and environmental outcomes.

RESULTS

From the 10,965 studies identified, 56 studies were included, mostly from high-income countries (n = 49). Iron (all 56) and iodine (n = 20) were the most and least reported MNs, respectively. There was one randomized controlled trial (RCT) that also provided the only biomarker data, 10 dietary intake studies, and 45 dietary modeling studies, including 29 diet optimization studies. Most studies sought to reduce greenhouse gas emissions or intake of animal-sourced foods. Most results suggested that intakes of zinc, calcium, iodine, and vitamins B12, A, and D would decrease, and total iron and folate would increase in a dietary transition to reduce environmental impacts. Risk of inadequate intakes of zinc, calcium, vitamins A, B12 and D were more likely to increase in the 10 studies that reported nutrient adequacy. Diet optimization (n = 29) demonstrated that meeting nutritional and environmental targets is technically feasible, although acceptability is not guaranteed.

CONCLUSIONS

Lower intakes and status of MNs of public health concern are a potential outcome of dietary changes to reduce environmental impacts. Adequate consideration of context and nutritional requirements is required to develop evidence-based recommendations. This study was registered prospectively with PROSPERO (CRD42021239713).

Effectiveness of current protein recommendations in adolescent athletes on a low-carbon diet

Adolescent athletes require adequate energy and nutrient supply to support growth, development, and the demands associated with exercise and training. However, they are susceptible to nutritional inadequacies affecting their health and physical performance. Food choices with nutrient adequacy and environmental protection is crucial for a sustainable diet. Therefore, we aimed to assess the adequacy of low-carbon diets to meet the protein requirements of adolescent athletes. Therefore, a cross-sectional observational study was conducted with 91 adolescent athletes from sports clubs in Rio de Janeiro who underwent anthropometric and food consumption assessments. To estimate the environmental impact of anthropogenic activities, the sustainability indicators carbon footprint (CF) and water footprint (WF) were used. The CF of the athlete's diet was compared with the benchmark of 1,571 g CO2eq/cap/d estimated by the World Wildlife Fund (WWF). Protein recommendations according to the American Dietetic Association (ADA) for athletes and protein food groups according to the low-carbon EAT-Lancet reference diet were used as references. The results were stratified by sport modality, age, sex, and income range. The Mann-Whitney test was performed, followed by the Kruskal-Wallis test with Dunn's post-hoc test to assess the differences between groups using the statistical program GraphPad PRISM® version 8.0. CF and WF were directly associated with total energy intake, total protein intake, animal-origin protein intake, and the food groups of meat and eggs. Significant differences were observed in the environmental impact of diet based on sports groups and gender. The athletes' profile with higher environmental impact was male, middle-income class, and of any age group. The quartiles of CF of the overall diets were above the 1,571 g CO2eq/cap/d benchmark. Additionally, ADA's recommended range of daily protein consumption was met by most athletes, even in the lowest quartile of CF. Thus, a diet with a lower environmental impact can meet protein recommendations in adolescent athletes. The results found are of interest to the sports and food industries. It could help in designing a balanced diet for athletes as well as ensure less negative environmental impacts of food production and consumption.

Sustainable Diets as Tools to Harmonize the Health of Individuals, Communities and the Planet: A Systematic Review

Background. Climate change and global health are inextricably linked. Thus, health systems and their professionals must adapt and evolve without losing quality of care. Aim(s). To identify health and environmental co-benefits derived from a sustainable diet and promotion strategies that favor its implementation. Methods. A systematic search for articles published on sustainable diets and human/planetary health published between 2013 and 2020 was conducted on the databases PubMed, Cinahl, Scopus and Trip from 4 to 7 May 2020 in accordance with the PRISMA guideline. Results. A total of 201 articles was retrieved, but only 21 were included. A calorie-balanced diet mainly based on food of plant origin that would allow the attainment of 60% of daily caloric requirements and a low protein intake from animal foods (focusing in fish and poultry) could significantly reduce global morbi-mortality and the dietary environmental impact maintaining a framework of sustainability conditioned by the consumption of fresh, seasonal, locally produced and minimally packaged products. Discussion. The implementation of sustainable diets requires working on the triangulation of concepts of food–health–environment from schools and that is permanently reinforced during all stages of the life by healthcare workers, who should establish the appropriate modifications according to the age, gender and health situation.

Shifting to a Sustainable Dietary Pattern in Iranian Population: Current Evidence and Future Directions

The need for a shift in diet toward a more sustainable one has reached an urgency in certain regions, including Iran, due to more rapid climate change and a higher level of vulnerability. This study was undertaken to identify and summarize available data on changes required in the current Iranian diet to make it more sustainable and the extent to which current policies in the country have addressed such a shift. In this study, PubMed, Scopus, and Web of science, as well as Iranian scientific search engines, including Scientific Information Database and Magiran, were systematically searched from January 1990 to July 2021. A total of 11 studies and policy analyses were included in this study. Based on the findings, moving Iranian diet toward sustainability will require increase in consumption of dairy, fruits, vegetables, cereals, poultry, and legumes and decrease in consumption of bread, rice, pasta, red meat, eggs, fats, sugars, and sweets. There has been a great deal of effort and investment on policies and strategies to decrease the amount of sugar, salt, and fat (specifically trans-fatty acids) in the Iranian diet, which makes it more sustainable healthwise. Several policies and programs have been implemented to tackle non-communicable diseases (NCDs) by reducing access to unhealthy foods, which is in line with health dimension of a sustainable diet. However, there is almost no direct address to ecological aspect of sustainable diet in the food and nutrition policy documents in the ccountry. Development of an enabling environment to a sustainable diet will require policy and actions to improve public awareness, support study to provide evidence and identify possible alternatives, and plan and implement interventions/programs to promote and facilitate healthy and sustainable diets.

Association between the socio-economic status of households and a more sustainable diet

OBJECTIVE

A sustainable diet is an affordable diet with low environmental impact, high food security and sufficient healthiness. The present study aimed to assess the correlation between the socio-economic status of households and a sustainable diet.

DESIGN

The food basket and socio-economic data of Iranian households were evaluated during 2016-2018. The households were classified based on the sustainability of their diet by determining the dietary carbon footprint, dietary water footprint, lower dietary costs of the household than the median and a higher dietary quality index than the median. Logistic regression was used with four models to calculate the OR of a more sustainable diet as the dependent variable regarding the different quartiles of socio-economic status (SES) as the independent variable.

SETTING

Iran.

PARTICIPANTS

Iranian households (n 102 303), nationally representative, were studied.

RESULTS

Lower SES was associated with the higher OR of a sustainable diet (OR: 0·90; (95 % CI 0·87, 0·91)). Higher quartiles of SES compared with the lower SES group indicated the higher energy intake and consumption of more dairies, meat, poultry, fish, eggs, legumes, nuts and fruits, as well as the lower intake of bread, cereal, rice and pasta.

CONCLUSION

In countries such as Iran, where nutrition transition occurs rapidly, better economic and social levels in the populations with a higher SES are associated with increased energy intake and higher consumption of animal-based foods, which decreases sustainable diets compared with the groups with a lower SES.

Absence of symbolic and sustainable aspects in recommendations for healthy eating: a qualitative analysis of food-based dietary guidelines

ABSTRACT Objective Was analyzed the contents of the main messages of food-based dietary guidelines to promote healthy eating, identifying nutritional, symbolic, and sustainable recommendations. Methods Food-based dietary guidelines from 90 different countries were analyzed. These guidelines were selected from the United Nations Food and Agriculture Organization database. For data extraction, all messages were exported to the Nvivo software and, after repeated readings, were grouped into predefined categories and corresponding dimensions based on the literature. The categories were created according to the mixed model, that is, they were created before data analysis was performed, but modified if necessary. Results Was identified 1,982 messages grouped into the following dimensions: nutritional (n=73.9%); sustainable (3.2%); symbolic (3.3%), and others (19.7%). All food-based dietary guidelines addressed nutritional aspects, and the most frequent recommendation was regarding the consumption of fats, followed by the consumption of salt and vegetables and fruits, cited by at least 75 food-based dietary guidelines. Less than half (n=40) of the food-based dietary guidelines addressed sustainable or symbolic aspects of food and 13 of the food-based dietary guidelines addressed both aspects. However, these messages represented only 6.5% of the total messages in the documents. Conclusions The recommendations for healthy eating in the food-based dietary guidelines are incipient in terms of sustainable and symbolic issues. Recommendations for adopting healthy diets need to consider the completeness of the food and its various combinations, dietary patterns, and the factors associated with their consumption, as well as the individual’s relations with food, environment, and society.

Designing a healthy, low-cost and environmentally sustainable food basket: an optimisation study

OBJECTIVE

Sustainable diets are diets with low environmental impacts and high affordability which contribute to food and nutrition security. The present study aimed to develop a healthy, low-cost and environmental-friendly food basket for Iran based on current consumption.

DESIGN

The Households Income and Expenditure Survey data were used. Linear Programming was utilised to obtain the optimal diets, separately, for each goal of the sustainable food basket: (1) Diet with maximum Nutrient Rich Food (NRF) index, (2) Diet with minimum cost, (3) Diet with the minimum water footprint and (4) Diet with the minimum carbon footprint. Goal Programming techniques were used to optimise the sustainable food basket by considering all goals simultaneously.

SETTING

Iran.

PARTICIPANTS

Households (n 100 500) in urban and rural areas of Iran, nationally representative.

RESULTS

In the 'optimal model', compared with the usual consumption, the amount of the 'bread, cereal, rice, and pasta', 'meat, poultry, fish, eggs, legumes, and nuts' and 'fats, oils, sugars, and sweets' groups was decreased. Inside those food groups, cereals, poultry and vegetable oil subgroups were increased. Also, dairy, fruits and vegetable groups were increased. In this model, there was a 14 % reduction in the total water footprint, a 14 % decrease in the total carbon footprint, a 23 % decrease in the cost and a 7 % increase in NRF of diet compared with the usual consumption.

CONCLUSIONS

Increasing the consumption of dairy, fruits and vegetables and reducing the consumption of bread, rice, pasta, meat, fish, eggs, legumes, nuts, hydrogenated fats and sugars are required to achieve a sustainable food basket.