Projected health effects of realistic dietary changes to address freshwater constraints in India: a modelling study

Abstract

SummaryBackgroundThe availability of freshwater for irrigation in the Indian agricultural sector is expected to decline over the coming decades. This might have implications for food production in India, with subsequent effects on diets and health. We identify realistic and healthy dietary changes that could enhance the resilience of the Indian food system to future decreases in water availability.MethodsIn this modelling study, we optimised typical dietary patterns in an Indian population sample to meet projected decreases in the availability of water per person for irrigation (blue water footprint) due to population growth (to 2025 and 2050). The optimised diets met nutritional guidelines and minimised deviation from existing patterns. Resulting changes in life-years lost due to coronary heart disease, stroke, diabetes, and cancers were modelled using life tables, and changes in greenhouse gas emissions associated with the production of diets were estimated. The primary outcomes of the model were changes in life-years per 100 000 total population over 40 years (to 2050).FindingsThe optimised diets had up to 30% lower blue water footprints and generally contained lower amounts of wheat, dairy, and poultry, and increased amounts of legumes. In the 2050 scenario, adoption of these diets would on average result in 6800 life-years gained per 100 000 total population (95% CI 1600–13 100) over 40 years. The dietary changes were accompanied by reductions in greenhouse gas emissions. The magnitude of the health and environmental effects varied between dietary patterns.InterpretationModest changes in diets could help to address projected reductions in the availability of freshwater for irrigation in India. These dietary changes could also simultaneously reduce diet-related greenhouse gas emissions and improve diet-related health outcomes.FundingWellcome Trust.

Environmental impacts of dietary shifts in India: A modelling study using nationally-representative data

“…Many studies over the last decade have now assessed the potential of using dietary change to improve health and environmental outcomes, though this literature has almost exclusively been focused on HICs, and analyses at the global level have not specifically assessed the impacts of improving diets for potentially undernourished populations (Aleksandrowicz et al, 2016). Recent work has begun to examine these relationships in LMICs (Milner et al, 2017; Rao et al, 2018; Arrieta and Gonzalez, 2018; Bahn et al, 2018; Lei and Shimokawa, 2017; Song et al, 2017). In China, two recent analyses found that national shifts to healthy diets would decrease footprints; in one case, annual national GHG emissions and blue WFs reduced by 1.7 ∗ 10 12 g and 2.7 ∗ 10 13 L, respectively (comparatively, using the 2012 Indian population (The World Bank, 2019), our results indicated an annual national increase of 2.8 ∗ 10 13 g and 9.2 ∗ 10 12 L, respectively) (Lei and Shimokawa, 2017), and a second analysis showed GHG emissions decreasing by about 12% (Song et al, 2017).…”

“…Recent work has shown that the much-needed shifts to healthy diets in selected Indian regions could partially buffer water-related pressures facing agricultural production, and decrease GHG emissions (Milner et al, 2017), and a national study also concluded that heathy dietary shifts could reduce GHG emissions (Rao et al, 2018). Here, we extend this work by combining, for the first time, nationally-representative dietary data with food-specific GHG emissions, water footprints (WFs), and land use (LU), to assess multiple environmental indicators.…”

Sustainable food systems—a health perspective

“…The substantial expected growth in the Indian population up to 2050 suggests that water use for Indian agriculture may increase unsustainably. In this context, recent optimisation modelling has identified that relatively small healthy dietary shifts in India could reduce dietary water footprints to meet future constraints, whilst minimising changes to cost and simultaneously cutting GHG emissions (Milner et al 2017 ). If adopted, these diets could improve population health in India; with the potential to gain 6800 life-years per 100,000 total population by 2050 (Milner et al 2017 ).…”

“…In this context, recent optimisation modelling has identified that relatively small healthy dietary shifts in India could reduce dietary water footprints to meet future constraints, whilst minimising changes to cost and simultaneously cutting GHG emissions (Milner et al 2017 ). If adopted, these diets could improve population health in India; with the potential to gain 6800 life-years per 100,000 total population by 2050 (Milner et al 2017 ). However, these dietary changes may need to be more severe in light of additional challenges such as climate change and rapid urbanisation.…”

Meeting the nutrition and water targets of the Sustainable Development Goals: achieving progress through linked interventions

“…Dietary preferences are changing, and unhealthy diets, with excess fats and meat, tend to have higher water footprints (Mateo-Sagasta et al 2018). A recent study suggests that, in India, even modest changes in diets could help address projected reductions in the availability of freshwater and improve diet-related health outcomes (Milner et al 2017). These issues have been described by the Water Footprint Network (http:// waterfootprint.org/en/), which visualizes the quantities of water used in daily activities, including food production and domestic water use, and indicates the pressures these uses exert on freshwater resources.…”