Alternative milk options have exploded in popularity in recent years through a continuously expanding selection of plant-based varieties. Synthetic milk is also working its way from the lab to the mainstream consumer. Choosing the best and healthiest milk to consume is not only about its type, protein, or fat content; it is also about safety, encompassing all ingredients and any adulterations included, such as added sugar, chemicals, or additives. The level of processing involved also must be considered, along with trust in the new industries that are disrupting the established dairy markets.
The majority of consumers accept bovine milk to be a rich source of quality proteins, essential amino acids, and calcium. However, other consumers are lactose intolerant, have milk allergies or sensitivities, follow diets that do not include animal products, or abstain from animal milk consumption for other reasons, such as environmental concerns. Dairy milk has a higher environmental footprint than plant-based alternatives; almost nine times more land is required to produce 1 liter of dairy milk compared with 1 liter of rice, soy, oat, or almond milk.1 Dairy's contribution to greenhouse gas emissions and eutrophication of water bodies is also disproportionately higher than those of alternatives milks (Figure 1). Dairy is responsible for the higher use of freshwater, but some plant-based milks exert more pressure than others on this resource. For example, it takes about 371.4 liters of water to produce 1 liter of almond milk due to the trees' high requirements for water usage and irrigation.2 Despite rice milk requiring around half of the water needed to produce the same amount of dairy milk, 1 liter of rice milk still requires 269.8 liters of water for production.2