A Comparative Analysis of Plant-Based Milk Alternatives Part 2: Environmental Impacts

Abstract

Human food production is the largest cause of global environmental changes. Environmental benefits could be achieved by replacing diets with a high amount of animal-sourced foods with more plant-based foods, due to their smaller environmental impacts. The objective of this study was to assess the environmental impacts of the three most common plant-based milk alternatives (PBMAs)—oat, soy, and almond drink—in comparison with conventional and organic cow milk. Life cycle assessments (LCA) were calculated by the ReCiPe 2016 midpoint method, in addition to the single issue methods “Ecosystem damage potential” and “Water scarcity index”. PBMAs achieved lower impact values in almost all 12 of the calculated impact categories, with oat drink and the organic soy drink being the most environmentally friendly. However, when LCA results were expressed per energy and by the protein content of the beverages, the ranking of the beverages, in terms of their environmental impacts, changed greatly, and the results of PBMAs approached those of milk, particularly with regard to the protein index. The study highlights the importance of considering a broader range of impact categories when comparing the impacts of PBMAs and milk.

Dairy and Plant-Based Milks: Implications for Nutrition and Planetary Health

“…Summaries of GHGe [ 64 - 67 , 69 - 78 68 ••, ] and water use [ 66 , 67 , 71 , 72 , 75 , 77 , 79 68 ••, ] comparing plant-based milks to cow’s milk, compiled from life cycle assessment studies, are shown in Fig. 3 and Table 3 (see Table S4 for study details).…”

“…Comparing water use associated with producing plant-based milks is complicated by the wide range of metrics used in the literature. Studies in our review measured blue water footprint (WF), i.e., freshwater withdrawals from ground and surface sources lost to evaporation or incorporated into the product, such as for irrigation [ 66 , 75 , 79 68 ••, ]; total WF, a combined measure of blue, green (rainwater available to plants), and grey (polluted) water [ 77 , 79 ]; and water withdrawals, which include all freshwater drawn from a source regardless of whether it returns to the watershed after use [ 71 ]. Some studies also weighted water use by the level of scarcity in the region from where it was withdrawn, for example, withdrawals from a water-scarce region such as California were weighted more heavily [ 67 , 72 , 77 , 80 68 ••, ].…”

“…Other environmental impacts were less well represented in the literature. Geburt et al [ 68 ••] found that oat milk scored as well as or better than both organic and conventional cow’s milk in all 12 of the environmental impacts examined, including land use, acidification and eutrophication potentials, ecotoxicity, and ecosystem damage. Soymilk scored similarly or better than cow’s milk for most of the same metrics [ 68 ••].…”

“…Geburt et al [ 68 ••] found that oat milk scored as well as or better than both organic and conventional cow’s milk in all 12 of the environmental impacts examined, including land use, acidification and eutrophication potentials, ecotoxicity, and ecosystem damage. Soymilk scored similarly or better than cow’s milk for most of the same metrics [ 68 ••]. As demonstrated by variations in water use and scarcity, many of these environmental impacts are specific to the regions where animals, feed crops, and plant-based milk raw materials are produced.…”

Beyond Plants: The Ultra-Processing of Global Diets Is Harming the Health of People, Places, and Planet

“…While soy, oat, almond, and rice, beverages were once a niche health food store market, the 2022 sales of these products exceeded US $3.1 billion dollars in the United States and US $20.9 billion globally [207]. Although at first glance such beverages appear to be superior to dairy milk in terms of environmental impact, such might not be the case when nutritional factors (protein and various nutrients) are brought into the assessment [208][209][210]. Almond milk, the number one dairy beverage alternative in the US, utilizes significant quantities of water during manufacturing [211].…”