By Judith Van Dongen, WSU Health Sciences Spokane Office of Research
SPOKANE, Wash. – Eating more plant-based proteins like beans, soy, nuts, and seeds could be the key to a more sustainable diet, according to a study conducted by nutrition researchers in the College of Medicine.
Unlike other assessments that use one or two measures, this study defined sustainable foods based on all four dimensions of food sustainability as defined by the Food and Agriculture Organization of the United Nations—nutrition, relatively low environmental impact, low price, and acceptability to people from a variety of backgrounds.
Published in the journal Sustainability, the study found that only 165 out of nearly 6,000 food items analyzed qualified as optimally sustainable. More than half of those, 94, were plant proteins.
The approach taken by the researchers could serve as a model for future efforts to identify and classify sustainable foods, which could ultimately inform consumer food choices and help policymakers address food production issues. These issues include food inequality, as well as agriculture’s use of limited resources like water and its contribution to loss of natural habitat, pollution, and climate change.
“If we can continue to advance this research and make it more easily accessible to the general population, our sustainability index could be very useful for people to be aware of the other impacts of their foods,” said first author Kayla Hooker, a recent graduate from the College of Medicine’s master of science in nutrition and exercise physiology program. “Because you can look at a food product’s nutrition label and perhaps understand it, you can consider the cost and know whether it will fit your budget, but you don’t necessarily know all these other aspects.”
The study used data from the Food and Nutrient Database for Dietary Studies, a federal database that lists nutrient values for foods and beverages reported as being consumed by U.S. residents in a national survey. The researchers linked this information to data from other sources on the nutrient density, retail price, environmental impact, and frequency of consumption of different foods. Items that were considered optimally sustainable were those that earned a sustainability index score of 4, which meant they were more sustainable on all four dimensions relative to other items in the same food group.
Of the 165 items the study identified as optimally sustainable, 62% were protein foods, with 92% of those being plant proteins. Fruits and vegetables each represented about 8% of the optimally sustainable items and grains about 7%. Dairy products accounted for less than 1% of all optimally sustainable items, with only one item earning the top score.
The researchers also found that more nutrient-dense foods such as many vegetables and fruits tended to have a lower environmental impact but were generally more expensive and less frequently consumed.
“When we recommend nutritious foods and diets to people, we shouldn’t be undermining our sustainability goals,” said senior study author Pablo Monsivais, an associate professor in the WSU Elson S. Floyd College of Medicine. “There can be contradictions between nutrition and sustainability, and this work is trying to identify choices that achieve all of those goals together.”
While the study provides support for shifting to diets that emphasize plant-based foods, the researchers said more research needs to be conducted before specific recommendations can be made. This includes work to further refine their sustainability index and incorporate newer, more detailed data on factors such as environmental impact and cost as they become available.