Feed our Future

For the global food system to be considered sustainable it must deliver enough nutrients to meet the needs of the global population. Researchers at the Riddet Institute have formed the Sustainable Nutrition Initiative (SNI), aiming to analyse how food production meets the nutritional needs of th

A balanced food system with nutrient-rich plant and animal foods is important. Equally as important to address are micro-nutrients and trace elements; the vitamins and minerals that are vital for human function. It is often not the macro-nutrients that limit the provision of adequate nutrition; rather, it is the micro-nutrients and trace elements such as iron, zinc, calcium, vitamin B12 and vitamin C. The richest and best-absorbed sources of calcium are milk products, which are also rich in other nutrients such as high-quality protein and vitamin B12. On the other hand, the best sources of vitamin C and fibre are plants.

The most common cause for concern with global diets is the need for increased protein supply, both now and in the future. Proteins consumed by the body supply the essential amino acids – nine amino acids that cannot be synthesised by the human body. It is important to consider bioavailable essential amino acid supply and not simply protein when assessing a global sustainable diet. Essential amino acid deficiencies can result in a range of health issues including decreased immunity, digestive problems, lower mental alertness or slowed growth in children. Long term consequences then have impacts both at the individual level and on national economic development and human capital.

The DELTA Model calculates the bioavailable nutrients supplied in a global food production scenario. This encompasses food production, processing, waste and other uses (e.g. animal fats in soap or sugar cane in biofuels).  The model output displays whether a food production scenario delivers adequate nutrition to everyone on the planet, or where it falls short if not. The model assumes that nutrition should come first in assessing future food production scenarios, and then moves to consider other aspects of sustainability, examining the associated environmental and socioeconomic consequences in later versions of the model. The model draws on food system and nutritional data from the FAO, USDA and the EFSA. Other models and recommendations of sustainable diets largely make the over-simplification that all foods are equal in bioavailability. The DELTA Model is an improvement on such models, because it adjusts for bioavailability when comparing nutrient supply against requirements.

A key observation from the model is that it is not feasible to meet the global nutrient requirements with only plant-based sources of nutrition, even with active sourcing of a wide variety of foods, and possibly supplementation and fortification. On a global population scale, this may not be practical or affordable. The options available to feed the world are not the same as options available to feed individuals, particularly in more affluent parts of the world where people have a lot more choice in their foods and diets. This does not mean the answer to the global food system is an abundance of animal foods. The current food system is plant dominant: 85% of all biomass that leaves the world’s farms is plant-based. The key is that a food system must be optimised with nutrient-rich foods to ensure global nutrient requirements are met. This means plant-food based and animal food optimised.

Once possible scenarios of how the world can be nourished are established, practicality of the food system and improvements required to deliver optimal outcomes must be considered. A solution that can nourish the average global citizen may not necessarily be a viable solution from a holistic view. Wider socioeconomic and environmental factors must be evaluated, such as land and its use, greenhouse gas emissions, water availability and quality, social and economic viability, and so on. If the other consequences of a scenario are not acceptable, then the performance of the environmental or socioeconomic outcomes need to be the focus for improvement. However, the DELTA Model puts nutrition first when assessing sustainable food production systems. Any food production systems that cannot adequately contribute to nourishing the world will be an inadequate use of the world’s scarce and valuable resources.

This article was originally published in the NZIFST Food Magazine, October 2020. This is an abridged version https://issuu.com/annescott1/docs/foodnzoctnov2020web 

Read more about the DELTA Model and the Sustainable Nutrition Initiative here: https://sustainablenutritioninitiative.com/ 

The Sustainable Nutrition Initiative team includes food scientists, nutrition scientists and mathematical modellers. Drs Nick Smith and Andrew Fletcher are currently working on improvements to the DELTA Model including land use, environmental footprinting, and examining New Zealand’s role in the global food system. SNI is led by Professor Warren McNabb. In addition to the DELTA Model, SNI also produces scientific articles on food system sustainability and provides commentary on food system sustainability research.
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