Featured article in the Fall 2018 Issue of Nutrition Close-Up; written by Mickey Rubin, PhD
Increasingly, the conversation among health professionals in nutrition includes not only human health and well-being, but also the intersection of food, nutrition and agriculture.
This intersection is commonly referred to as sustainable nutrition, and it is a way of looking at the contribution of foods and diet patterns in terms of not only health benefits, but economic, social and environmental outcomes as well.
A new study published in the journal Lancet Planet Health aimed to quantify measures of sustainability in recommended diet patterns by assessing their environmental impact.1 The authors examined the environmental impact of the three recommended dietary patterns from the 2015-2020 Dietary Guidelines for Americans, which includes the Healthy U.S. pattern, the Healthy Mediterranean pattern, and the Healthy Vegetarian pattern that includes eggs and dairy foods – as the DGA states that most self-identified vegetarians consume eggs and dairy.2 This analysis required incorporating results from environmental science research that utilizes life cycle assessments to understand the environmental impact of producing the foods that make up the diet patterns. The researchers examined several environmental categories for each pattern, including greenhouse gas emissions, land use, water use, water eutrophication and air particle pollution.
The results of this study indicate that the Healthy Vegetarian pattern from the Dietary Guidelines for Americans had between 42-84% lower environmental burden than the Healthy U.S. and the Healthy Mediterranean patterns. The researchers report that this was due in part to the use of eggs, as well as plant-based protein sources, in the vegetarian pattern versus other sources of protein that have a comparatively higher environmental footprint.
This study clearly illustrates that the environmental impact of food production is not solely about greenhouse gases. There are a host of other important environmental factors we must understand, such as water use and land use, that contribute to a holistic understanding of the interaction of food, nutrition and the environment. We must evaluate all of these factors if we want to continue making strides to improve efficiencies in our food production system. Consider the environmental footprint of egg production as an example, in which life cycle assessment research has shown that from 1960 to 2010, one kilogram of egg production has reduced greenhouse gas emissions by 71% and water use by 32%, all while producing more eggs with fewer hens that are healthier and living longer.3
It is also important to consider factors not included in this study for a comprehensive evaluation. Sustainable diets are about more than just environmental impact. In fact, the Food and Agriculture Organization (FAO) of the United Nations has a broad definition of sustainable diets that is inclusive of not only nutrition and the environment, but also economics and society. These factors are known as the four domains of sustainable diets, and together they underscore that sustainable food patterns must not only be nutritionally adequate, but also economically affordable, socially acceptable, all while sparing of ecosystems and biodiversity.4
Perhaps there is no better example of a contribution to nutritionally adequate and societal aspects of sustainable diets than in a recent randomized controlled trial known as the Lulun Project. Conducted in Cotopaxi Province, Ecuador, the Lulun Project was a randomized controlled trial in which children ages 6 to 9 months received 1 egg per day for 6 months compared to a control with no intervention.5 The results indicated that early introduction of eggs significantly improved growth in young children while reducing prevalence of stunting by 47%. With undernutrition remaining a significant problem in many parts of the world, this study provides evidence that eggs can be a nutrient-rich, affordable and culturally acceptable part of the solution.
As we continue to make strides in understanding the interaction of the nutritional and environmental components of sustainable nutrition we must not lose sight of the societal and economic components of the definition. Foods may be nutrient-rich and with a low environmental burden, but must be affordable, have a positive impact on the community and be culturally acceptable for people to consume them.