25 June 2019

Scientists call for sustainable sandwiches to be more nutritious

After discovering more sustainable sandwiches contain fewer vital nutrients, scientists call on the catering industry to support a shift to sustainable diets by providing more nutritionally optimal plant-based options.

Coffee Revolution

Vegan food and drink options are healthier in some ways because they are lower in calories, salt, saturated fat and sugars – but contain less iron and vitamin B12, according to new research.

The researchers from the University of Sheffield’s Grantham Centre for Sustainable Futures and Institute for Sustainable Food are now calling for the catering industry to support a shift to sustainable diets by providing more nutritionally optimal sustainable options.

Sandwiches comprise a large proportion of food consumed outside the home in the UK, with four billion pre-packed sandwiches sold in 2018 – while the non-alcoholic drinks market continues to grow, with sales of coffee products alone generating an estimated turnover of £3.2 billion.

The study, published in Sustainability, found that beef sandwiches and milk-based drinks had the highest environmental impact – based on their water use and greenhouse gas emissions – and vegan options the lowest.

High-impact sandwiches and beverages tended to have more calories, protein, carbohydrates, total fat, saturated fat, iron and sugars – but because the more sustainable choices did not contain animal products, they were lower in two micronutrients: iron and vitamin B12.

Most of the vegetarian options contained cheese, which was found to be more damaging for the environment than chicken or eggs – suggesting that vegetarian sandwiches aren’t always more environmentally friendly than meat.

When it comes to drinks, the study showed that those containing milk, cocoa or coffee had the highest environmental impact. Choosing a milk-based drink over a sugar-sweetened one could therefore be better for health but less environmentally friendly, highlighting possible tensions between nutrition and sustainability.

The scientists highlighted the important role the catering sector has in supporting the shift towards diets that are healthier and more environmentally friendly, and it is hoped the research might encourage a step-change in the industry in terms of providing more nutritionally optimal sustainable options.

The University of Sheffield, which is already piloting a scheme to reduce high impact product lines, and promoting more plant-based options in its catering outlets, is considering how it can further implement the findings of the study by ensuring campus cafes provide healthier low-impact choices.

Dr Fiona Graham from the Institute for Sustainable Food, a Research Associate at the University of Sheffield’s School of Health and Related Research (ScHARR), was the lead author of the study. She said: “As the climate emergency accelerates, it’s crucial that we shift towards more sustainable diets – but our study found that cafes provided fewer low impact options to choose from and those available contained fewer important micronutrients.

“There is huge potential for more plant-based diets to tackle the climate crisis and improve public health – but the catering industry has a responsibility to offer more nutritious options, so people can more easily make healthy and environmentally sustainable choices.

“I’m pleased to see the University of Sheffield is taking this research into account as it develops its sustainability strategy.”

Caryn Masters, Director of Accommodation and Commercial Services at the University, said: “The University of Sheffield’s world-leading academics are working on a range of sustainability challenges. As professional staff, we’re always looking to use that academic expertise to inform and improve sustainability on campus, and we are always keen to support university research activities.

“Diet choices are one of the key ways we can help our staff and students to reduce their impact on the environment, but this study shows that sustainability needs to be balanced with nutrition. We’ll be considering the findings carefully to understand what changes to make in consultation with the university community.”

The Institute for Sustainable Food at the University of Sheffield brings together multidisciplinary expertise and world-class research facilities to help achieve food security and protect the natural resources we all depend on.

The Grantham Centre for Sustainable Futures is a hub of outstanding interdisciplinary research and innovative sustainability solutions with a focus on reducing global consumption and ensuring everyone has enough clean water, nutritious food and green energy to meet their needs.

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