Optimisation modelling to assess cost of dietary improvement in remote Aboriginal Australia

Precision nutrition for type 2 diabetes in Benin: leveraging linear goal programming to optimize diets with emphasis on adequacy, affordability, accessibility, and culture

Background

Nutrition and diet are critical to managing Type 2 diabetes (T2D). Low-income households often face challenges maintaining a healthy and balanced diet due to food insecurity, availability, and cost. To address this issue, we used a linear goal programming (LGP) model to develop nutritionally adequate, affordable, accessible, and culturally acceptable diets for persons with T2D in Benin, a French-speaking sub-Saharan country. The goal was to help persons with T2D manage their condition more effectively.

Methods

We compiled a robust list of local commonly consumed foods in Benin, and calculated their nutritional value using West African food composition tables and food costs per serving from a market survey. Using mathematical optimization techniques, we designed dietary plans that meet the daily nutrient intake recommended by the World Health Organization (WHO) to prevent chronic diseases in normal adults. While adhering to dietary constraints of T2D, we developed optimized diet plans with varying energy levels that meet all nutrient requirements while considering availability, acceptability, and budgetary constraints.

Results

Fifty-two food items and recipes were evaluated to create six low-cost daily menus. Menu 1 was the most affordable at CFA 1,127 (USD 1.88), providing 1890 kcal of energy, while Menu 6 was the most expensive at CFA 1,227 (USD 2.05), providing 1749 kcal. All the menus met the daily WHO minimum requirements for carbohydrates, fat, cholesterol, and fiber content, while other nutrients such as protein, vitamin C, and iron reached the upper limits of the acceptable value range.

Conclusion

Linear goal programming can be an effective tool in helping to obtain optimized adequate, accessible, and culturally acceptable diets at minimal cost by interpreting and translating dietary recommendations into a nutritional model, based on local market prices.

Assessing the Cost of Healthy and Unhealthy Diets: A Systematic Review of Methods

PURPOSE OF REVIEW

Poor diets are a leading risk factor for chronic disease globally. Research suggests healthy foods are often harder to access, more expensive, and of a lower quality in rural/remote or low-income/high minority areas. Food pricing studies are frequently undertaken to explore food affordability. We aimed to capture and summarise food environment costing methodologies used in both urban and rural settings.

RECENT FINDINGS

Our systematic review of high-income countries between 2006 and 2021 found 100 relevant food pricing studies. Most were conducted in the USA (n = 47) and Australia (n = 24), predominantly in urban areas (n = 74) and cross-sectional in design (n = 76). All described a data collection methodology, with just over half (n = 57) using a named instrument. The main purpose for studies was to monitor food pricing, predominantly using the 'food basket', followed by the Nutrition Environment Measures Survey for Stores (NEMS-S). Comparatively, the Healthy Diets Australian Standardised Affordability and Price (ASAP) instrument supplied data on relative affordability to household incomes. Future research would benefit from a universal instrument reflecting geographic and socio-cultural context and collecting longitudinal data to inform and evaluate initiatives targeting food affordability, availability, and accessibility.

Development of an optimal grocery list based on actual intake from a cross-sectional study of First Nations adults in Ontario, Canada

A multi-stage sampling strategy selected 1387 on-reserve First Nations adults in Ontario. Foods from a 24-hour dietary recall were assigned to the 100 most common food groups for men and women. Nutrients from market foods (MF) and traditional foods (TF) harvested from the wild as well as MF costs were assigned based on the proportions of total grams consumed. Linear programming was performed imposing various constraints to determine whether it was possible to develop diets that included the most popular foods while meeting Institute of Medicine guidelines. Final models were obtained for both sexes with the top 100 food groups consumed while limiting the nutrient-poor foods to no more than the actual observed intake. These models met all nutrient constraints for men but those for dietary fibre, linoleic acid, phosphorus, and potassium were removed for women. MF costs were obtained from community retailers and online resources. A grocery list was then developed and MF were costed for a family of four. The grocery list underestimated the actual weekly food cost because TF was not included. Contemporary observed diets deviated from healthier historic First Nations diets. A culturally appropriate diet would include more traditional First Nations foods and fewer MF. Novelty ● Linear programming is a mathematical approach to evaluating the diets of First Nations ● The grocery list is representative of food patterns within Ontario First Nations and can be used as an alternative to the nutritious food basket used for public health food costing.

The Retail Food Sector and Indigenous Peoples in High-Income Countries: A Systematic Scoping Review

Indigenous Peoples in high-income countries experience higher burdens of food insecurity, obesity, and diet-related health conditions compared to national averages. The objective of this systematic scoping review is to synthesize information from the published literature on the methods/approaches, findings, and scope for research and interventions on the retail food sector servicing Indigenous Peoples in high-income countries. A structured literature search in two major international databases yielded 139 relevant peer-reviewed articles from nine countries. Most research was conducted in Oceania and North America, and in rural and remote regions. Several convergent issues were identified across global regions including limited grocery store availability/access, heightened exposure to unhealthy food environments, inadequate market food supplies (i.e., high prices, limited availability, and poor quality), and common underlying structural factors including socio-economic inequality and colonialism. A list of actions that can modify the nature and structure of retailing systems to enhance the availability, accessibility, and quality of healthful foods is identified. While continuing to (re)align research with community priorities, international collaboration may foster enhanced opportunities to strengthen the evidence base for policy and practice and contribute to the amelioration of diet quality and health at the population level.

Optimisation modelling to improve the diets of First Nations individuals

We examined the feasibility of linear programming (LP) to develop diets that were economical, included traditional (cultural, non-market) foods and met the dietary reference intakes (DRI) in a Canadian Indigenous population. Diet optimisation using LP is a mathematical technique that can develop food-based dietary guidelines for healthy eating in Indigenous populations where food insecurity, availability and cost are important considerations. It is a means of developing nutritionally optimal food combinations that are based on economical and culture-specific foods. Observed food consumption data were derived using 24-h food recalls from the First Nations Food, Nutrition and Environment Study. The LP models were constructed to develop diets meeting DRI, cost and food constraints. Achieving the recommended food intake was not feasible in a model meeting all nutrient requirements. Models that met most nutrient requirements at reduced cost were designed for men and women, separately. In women, it was necessary to increase energy intake to meet most nutrient requirements. Nutrient requirements could not be met for fibre, linoleic and linolenic acids, vitamin D, Ca and K in both sexes, P in women, and Mg and vitamin A in men. Using LP to develop optimal diets for First Nations people, we found simultaneous achievement of all DRI was difficult, suggesting that supplementation might be necessary which goes against recommendations for individuals to meet their nutrient needs through healthy eating patterns. Additionally, to make diets feasible, programmes to reduce market food costs and to support First Nations people in traditional food harvesting are recommended.

Sugar-sweetened beverage (SSB) consumption, correlates and interventions among Australian Aboriginal and Torres Strait Islander communities: a scoping review

OBJECTIVES

Sugar-sweetened beverage (SSB) consumption in Australian Aboriginal and Torres Strait Islander people is reported to be disproportionally high compared with the general Australian population. This review aimed to scope the literature documenting SSB consumption and interventions to reduce SSB consumption among Australian Aboriginal and Torres Strait Islander people. Findings will inform strategies to address SSB consumption in Aboriginal and Torres Strait Islander communities.

METHODS

PubMed, SCOPUS, CINAHL, Informit, Joanna Briggs Institute EBP, Mura databases and grey literature were searched for articles published between January 1980 and June 2018. Studies were included if providing data specific to an Australian Aboriginal and/or Torres Strait Islander population's SSB consumption or an intervention that focused on reducing SSB consumption in this population.

DESIGN

Systematic scoping review.

RESULTS

59 articles were included (1846 screened). While reported SSB consumption was high, there were age-related and community-related differences observed in some studies. Most studies were conducted in remote or rural settings. Implementation of nutrition interventions that included an SSB component has built progressively in remote communities since the 1980s with a growing focus on community-driven, culturally sensitive approaches. More recent studies have focused exclusively on SSB consumption. Key SSB-related intervention elements included incentivising healthier options; reducing availability of less-healthy options; nutrition education; multifaceted or policy implementation (store nutrition or government policy).

CONCLUSIONS

There was a relatively large number of studies reporting data on SSB consumption and/or sales, predominantly from remote and rural settings. During analysis it was subjectively clear that the more impactful studies were those which were community driven or involved extensive community consultation and collaboration. Extracting additional SSB-specific consumption data from an existing nationally representative survey of Aboriginal and Torres Strait Islander people could provide detailed information for demographic subgroups and benchmarks for future interventions. It is recommended that a consistent, culturally appropriate, set of consumption measures be developed.

Taking dietary habits into account: A computational method for modeling food choices that goes beyond price

Computational models have gained popularity as a predictive tool for assessing proposed policy changes affecting dietary choice. Specifically, they have been used for modeling dietary changes in response to economic interventions, such as price and income changes. Herein, we present a novel addition to this type of model by incorporating habitual behaviors that drive individuals to maintain or conform to prior eating patterns. We examine our method in a simulated case study of food choice behaviors of low-income adults in the US. We use data from several national datasets, including the National Health and Nutrition Examination Survey (NHANES), the US Bureau of Labor Statistics and the USDA, to parameterize our model and develop predictive capabilities in 1) quantifying the influence of prior diet preferences when food budgets are increased and 2) simulating the income elasticities of demand for four food categories. Food budgets can increase because of greater affordability (due to food aid and other nutritional assistance programs), or because of higher income. Our model predictions indicate that low-income adults consume unhealthy diets when they have highly constrained budgets, but that even after budget constraints are relaxed, these unhealthy eating behaviors are maintained. Specifically, diets in this population, before and after changes in food budgets, are characterized by relatively low consumption of fruits and vegetables and high consumption of fat. The model results for income elasticities also show almost no change in consumption of fruit and fat in response to changes in income, which is in agreement with data from the World Bank's International Comparison Program (ICP). Hence, the proposed method can be used in assessing the influences of habitual dietary patterns on the effectiveness of food policies.

Effect of 25% Sodium Reduction on Sales of a Top-Selling Bread in Remote Indigenous Australian Community Stores: A Controlled Intervention Trial

Reducing sodium in the food supply is key to achieving population salt targets, but maintaining sales is important to ensuring commercial viability and maximising clinical impact. We investigated whether 25% sodium reduction in a top-selling bread affected sales in 26 remote Indigenous community stores. After a 23-week baseline period, 11 control stores received the regular-salt bread (400 mg Na/100 g) and 15 intervention stores received the reduced-salt version (300 mg Na/100 g) for 12-weeks. Sales data were collected to examine difference between groups in change from baseline to follow-up (effect size) in sales (primary outcome) or sodium density, analysed using a mixed model. There was no significant effect on market share (-0.31%; 95% CI -0.68, 0.07; p = 0.11) or weekly dollars ($58; -149, 266; p = 0.58). Sodium density of all purchases was not significantly reduced (-8 mg Na/MJ; -18, 2; p = 0.14), but 25% reduction across all bread could significantly reduce sodium (-12; -23, -1; p = 0.03). We found 25% salt reduction in a top-selling bread did not affect sales in remote Indigenous community stores. If achieved across all breads, estimated salt intake in remote Indigenous Australian communities would be reduced by approximately 15% of the magnitude needed to achieve population salt targets, which could lead to significant health gains at the population-level.

Fluctuations in money availability within an income cycle impacts diet quality of remote Indigenous Australians

OBJECTIVE

To consider the plausible nutritional impacts of fluctuations in money availability within an income cycle for remote Indigenous Australians.

DESIGN

Community-level dietary intake (energy, micro/macronutrients) and expenditure on foods and beverages (F&B) were estimated over one year for three remote Indigenous Australian communities (Northern Territory, Australia) using monthly F&B transaction data. F&B that were likely to be consumed during a period within an income cycle when money was relatively limited (low money period (LMP) foods) were identified by panel consensus and scenario modelling was conducted to simulate the nutritional outcomes of a range of F&B selection responses to having an LMP.

RESULTS

All scenarios resulted in reduced diet quality during the LMP relative to overall average diet values. Protein and fat energy percentages were reduced and carbohydrate energy percentage increased. Despite reduced expenditure, declines in energy intake were typically buffered due to the reduced energy cost ($AU/MJ) of the LMP diet. The micronutrient profile of the LMP diet was substantially poorer, such that additional key micronutrients dropped below population-weighted Estimated Average Requirements/Adequate Intakes.

CONCLUSIONS

The modelling undertaken herein suggests that even a short period of low money within an income cycle may noticeably contribute to the reduced diet quality of remote Indigenous Australians and exacerbate lifestyle disease risk. Dietary strategies that are designed to respond to diets and expenditure during different income cycle periods, rather than the overall average diet and expenditure, should be considered for improving diet quality and reducing cardiometabolic disease risk in remote Indigenous Australians.

Detection of 12.5% and 25% Salt Reduction in Bread in a Remote Indigenous Australian Community

Food reformulation is an important strategy to reduce the excess salt intake observed in remote Indigenous Australia. We aimed to examine whether 12.5% and 25% salt reduction in bread is detectable, and, if so, whether acceptability is changed, in a sample of adults living in a remote Indigenous community in the Northern Territory of Australia. Convenience samples were recruited for testing of reduced-salt (300 and 350 mg Na/100 g) versus Standard (~400 mg Na/100 g) white and wholemeal breads (n = 62 for white; n = 72 for wholemeal). Triangle testing was used to examine whether participants could detect a difference between the breads. Liking of each bread was also measured; standard consumer acceptability questionnaires were modified to maximise cultural appropriateness and understanding. Participants were unable to detect a difference between Standard and reduced-salt breads (all p values > 0.05 when analysed using binomial probability). Further, as expected, liking of the breads was not changed with salt reduction (all p values > 0.05 when analysed using ANOVA). Reducing salt in products commonly purchased in remote Indigenous communities has potential as an equitable, cost-effective and sustainable strategy to reduce population salt intake and reduce risk of chronic disease, without the barriers associated with strategies that require individual behaviour change.

Dietary sodium and iodine in remote Indigenous Australian communities: will salt-reduction strategies increase risk of iodine deficiency? A cross-sectional analysis and simulation study

Background

Excess salt intake is a global issue. Effective salt-reduction strategies are needed, however, as salt is a vehicle for iodine fortification, these strategies may also reduce iodine intake. This study examines the case of the remote Indigenous Australian population; we employed an innovative, objective method to assess sodium and iodine intakes against requirements and modelled the potential effects of salt-reduction strategies on estimated sodium and iodine intakes.

Design

Store-sales data were collected from 20 remote Indigenous community stores in 2012–14 representing the main source of food for 2 years for ~8300 individuals. Estimated average sodium and iodine intakes were compared against recommendations (nutrient reference values weighted to age and gender distribution). Linear programming was employed to simulate potential effects of salt-reduction strategies on estimated sodium and iodine intakes.

Results

Estimated average sodium intake was 2770 (range within communities 2410–3450) mg/day, far exceeding the population-weighted upper limit (2060 mg/day). Discretionary (added) salt, bread and processed meat were the biggest contributors providing 46 % of all sodium. Estimated average iodine intake was within recommendations at 206 (186–246) μg/day. The following scenarios enabled modelling of estimated average salt intake to within recommendations: 1) 67 % reduction in sodium content of bread and discretionary salt intake, 2) 38 % reduction in sodium content of all processed foods, 3) 30 % reduction in sodium content of all processed foods and discretionary salt intake. In all scenarios, simulated average iodine intakes remained within recommendations.

Conclusions

Salt intakes of the remote Indigenous Australian population are far above recommendations, likely contributing to the high prevalence of hypertension and cardiovascular mortality experienced by this population. Salt-reduction strategies could considerably reduce salt intake in this population without increasing risk of iodine deficiency at the population-level. These data add to the global evidence informing salt-reduction strategies and the evidence that these strategies can be synergistically implemented with iodine deficiency elimination programmes.

Trial registration

Australian New Zealand Clinical Trials Registry: ACTRN12613000694718.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2686-1) contains supplementary material, which is available to authorized users.

The economic feasibility of price discounts to improve diet in Australian Aboriginal remote communities

OBJECTIVE

To estimate the cost-effectiveness of fiscal measures applied in remote community food stores for Aboriginal Australians.

METHODS

Six price discount strategies on fruit, vegetables, diet drinks and water were modelled. Baseline diet was measured as 12 months' actual food sales data in three remote Aboriginal communities. Discount-induced changes in food purchases were based on published price elasticity data while the weight of the daily diet was assumed constant. Dietary change was converted to change in sodium and energy intake, and body mass index (BMI) over a 12-month period. Improved lifetime health outcomes, modelled for the remote population of Aboriginal and Torres Strait Islanders, were converted to disability adjusted life years (DALYs) saved using a proportional multistate lifetable model populated with diet-related disease risks and Aboriginal and Torres Strait Islander rates of disease.

RESULTS

While dietary change was small, five of the six price discount strategies were estimated as cost-effective, below a $50,000/DALY threshold.

CONCLUSION

Stakeholders are committed to finding ways to reduce important inequalities in health status between Aboriginal and Torres Strait Islanders and non-Indigenous Australians. Price discounts offer potential to improve Aboriginal and Torres Strait Islander health. Verification of these results by trial-based research coupled with consideration of factors important to all stakeholders is needed.

An ethnographic action research study to investigate the experiences of Bindjareb women participating in the cooking and nutrition component of an Aboriginal health promotion programme in regional Western Australia

Objective

To investigate the experiences of women participating in a cooking and nutrition component of a health promotion research initiative in an Australian Aboriginal regional community.

Design

Weekly facilitated cooking and nutrition classes were conducted during school terms over 12 months. An ethnographic action research study was conducted for the programme duration with data gathered by participant and direct observation, four yarning groups and six individual yarning sessions. The aim was to determine the ways the cooking and nutrition component facilitated lifestyle change, enabled engagement, encouraged community ownership and influenced community action.

Setting

Regional Bindjareb community in the Nyungar nation of Western Australia.

Subjects

A sample of seventeen Aboriginal women aged between 18 and 60 years from the two kinships in two towns in one shire took part in the study. The recruitment and consent process was managed by community Elders and leaders.

Results

Major themes emerged highlighting the development of participants and their recognition of the need for change: the impact of history on current nutritional health of Indigenous Australians; acknowledging shame; challenges of change around nutrition and healthy eating; the undermining effect of mistrust and limited resources; the importance of community control when developing health promotion programmes; finding life purpose through learning; and the need for planning and partnerships to achieve community determination.

Conclusions

Suggested principles for developing cooking and nutrition interventions are: consideration of community needs; understanding the impact of historical factors on health; understanding family and community tensions; and the engagement of long-term partnerships to develop community determination.