Course:CONS200/2020/Environmental impacts of milk alternatives: Which is the most sustainable option?

The environmental impacts and ethical considerations of milk production has increased GHG emissions, energy use, and land use around the world. Milk alternatives such as plant-based dairy products have been invented to promote sustainable resources that decreases the biodiversity impacts of dairy production. However, due to the increase in consumption and production of these non-dairy products, they have been linked to higher concentrations of greenhouse gases (GHG) in the atmosphere, which has in turn led to global warming and GHG emissions. Although, dairy milk production uses more water than soy and oat milk alternatives, dairy production still uses less water than rice and almond milk. More research today depicts the environmental impact non-dairy milk has on sustainability, in which the increase in demands for milk alternatives that disregard water, land, and environmental energy usage possibly have an adverse effect such as soy milk. Hence, from the common milk alternatives of soy, almond, oat, rice, and hemp milk, the most sustainable option will be identified with regards to environmental factors, including the potential harmful effects of both milk and milk alternatives on the planet for consumers to make environmentally friendly choices.

History of Milk Alternatives

Photograph of the S.K. Stone Dairy Farm in Keene New Hampshire.

Cow milk has been a fundamental part of human nutrition for more than 8000 years. The essential nutrients that cow milk contains has gives it an influential role in dietary recommendations around the world. However, dairy production has a negative impact on the environment making it a less sustainable option. Main issues related to cow milk production are soil degradation, air and water pollution, and loss of biodiversity. These problems have influenced scientists to produce non-dairy milk alternatives that are more sustainable than cow-milk products.

The increase in factors of lactose intolerance, milk allergies, environmental concerns, and high cholesterol diets in dairy products have even caused debates on the internet from critics. The discussion of whether or not milk is sustainable has made society to believe that plant-based milk alternatives are healthy, sustainable, and animal friendly. This has increased the number of plant-based dairy alternatives based on soy, seeds, nuts, legumes, and cereals, influencing higher consumption and production in many countries.The rise in popularity of milk alternatives has made it become a lifestyle that is consumed not only for its dietary value, but also because of consumers' individual beliefs. Worldwide, the growth of the plant-based milk market has made it become more mainstream. In modern society today, the economic success of milk alternatives has further developed and explored the fast-growing food market to deliver products that fit consumer preferences. Consequently, milk alternatives could replace and complement dairy products in the human diet, potentially reducing the amount of environmental impact of food consumption.

Originating about 2000 years ago in China, soy milk was the first plant-based milk product that became popular replacement for those with allergies to milk proteins and lactose intolerance. The main factors to consume soy products were lactose intolerance, starting a vegetarian diet, and environmental concerns. Due to the high cholesterol, fat and energy content of cow-milk, consumers believed that plant-based products, especially soy, would provide them with the same amount of nutritional and health benefits as dairy milk. The exceptional taste of soy-milk was the reason to continue the consumption of soy products for some people. However, higher costs and reduced availability were the main barriers against the consumption of soy products.

Over the last decade, studies have been done to find milk alternatives that fit consumers ideal lifestyle. The motives of most plant-based milk consumers were to be vegetarian in order to live healthy, other reasons ranged from ethical, taste, social, environmental, and economic aspects. Today, many studies report that animal welfare, especially for vegans, is the main reason to pursue a vegetarian lifestyle, including wellness, health, and environmental concerns. Nonetheless, the rise in consumption and production of milk alternatives has resulted from the health and environmental motives of consumers that continue to support farmers and the local economy to supply various alternatives to dairy-based products.

More recently, research has been directed towards cereals, seeds, and nuts as other alternatives to dairy-based products. Plant-based milk products are a rising trend that can serve as an inexpensive alternative to poorer economic groups of developing countries that lack sufficient supply of cow's milk. Though the majority of these plant-based alternatives do not provide enough nutritional balance to people's diets, innovative technologies related to processing and preservation have been created to attract health conscious consumers. New and advanced non-thermal processing technologies such as ultra high temperature treatment, ultra high pressure homogenization, pulsed electric field processing are being researched to tackle the problems related to increasing shelf life, emulsion stability, nutritional completeness and sensory acceptability.

The increasing demand for milk alternatives has led to the rise in consumption and production of plant-based dairy alternatives such as soy, seeds, nuts, legumes, and cereals. Producers of the dairy market have provided similar alternatives that agree with society's belief that these alternatives are a more healthy and environmentally friendly option. However, just like soy milk, the new technology used to provide milk alternatives emit a high amount of greenhouse gas (GHG) emissions that can also enhance global warming compared to only cow's milk. The consequences of providing plant-based milk alternatives that fit consumers beliefs and perspectives about milk has influenced more production and consumption of these products, leading to higher gas emissions, land and water use. The growth of plant-based milk products has been believed to reduce the environmental impacts of milk production, yet, the further enhancement of technology and methods to provide sustainable milk alternatives can also inhibit environmental impacts similar to that of dairy milk.

Milk Substitutes

Milk alternatives help people achieve a healthy lifestyle while remaining environmentally friendly. For example, those that are lactose intolerant can obtain nutrients while avoiding dairy. Common alternative milks include those derived from soy, almond, rice, oat, coconut, hemp and cashew.

Soy milk

Soy milk is a popular plant-based milk alternative. The production process begins with soaking the soybeans before grinding them into a fine powder. The mixture is then boiled and filtered to remove the remaining particles. It is for individuals who are lactose intolerant and by people with environmental and serious health concerns about the production and intake of dairy.

During production, soy milk is often fortified with vitamins A and D as well as calcium and riboflavin. It has the closest nutritional profile to dairy compared to other milk alternatives. A single cup of soy milk contains 105 calories, 12 grams of carbohydrates, approximately 8.9 grams of sugar, 6.35 grams of proteins, 2.68 micrograms of vitamin D, 2.07 micrograms of vitamin B-12, 300 milligrams of calcium, 298 milligrams of potassium and zero milligrams of cholesterol. The uniqueness of soy milk is that it contains isoflavones which are naturally occurring antioxidants associated with reducing the risk of heart disease. Additionally, a 2014 article suggests that consuming around 10 milligrams of isoflavones can result in a 25% decrease in breast cancer relapse.

Consuming soy milk is beneficial to many groups, one of which is women. Apart from aiding in breast cancer recurrence reduction, it may also be beneficial both during and after menopause. Soy contains and provides compounds called phytoestrogens which tends to mimic the function of estrogen in the body. It has also been suggested that consuming soymilk helps reduce the hot flashes. One thing to take note of is soy milk can never be used as a suitable replacement to breastmilk and formula. Soy milk has a high content of mono-saturated and poly-saturated fats. Soy milk has its downsides too; despite the fact that it contains protein, some soy milk brands are deficient in essential amino acid such as methionine . This is the result of most manufacturing processes. Lack of the methionine, calcium and vitamin D renders soy milk a useless substitute for dairy milk. Soy milk also contains compounds that people refer to as antinutrients. These are known to reduce the body’s ability to absorb essential nutrients and can also impair digestion of proteins and carbohydrates. Examples of the antinutrients contained in soy milk through soybeans include; trypsin inhibitors, phytic acids, indigestible oligosaccharides and lectins. However, the antinutrients are reduced and the nutritional values enhanced throughout the manufacturing process.

From an ecological aspect, soy milk requires a significant amount of land to harvest the soybeans, especially for a large-scale production. For instance, there are many areas of the Amazon forest which have been cleared for harvesting soybeans. The clearance of the trees destroys natural habitats and decreases species diversity by releasing carbon dioxide that contributes to climate change. The large-scale production of soybeans also requires greater pesticide usage, which is harmful to species living nearby and could contaminate nearby water. Soy milk has the highest production rate of greenhouse gas compared to other milk alternatives, every 200ml glass of soy milk is responsible for around 0.195kg of carbon dioxide. However, the water usage for soy milk is less than a third of the water needed to produce dairy milk, requiring 297 litres of water to produce 1 litter of soy milk.

Almond Milk

Almond milk is produced by stirring almonds with water, then spraining the mixture to remove the solids. It can also be realized by diluting almond butter with water. It has a nutty flavor also has similarities to the dairy milk and soymilk. Ideal for those who are intolerable and allergic to dairy, almond milk has its own share of rich benefits .

While nutritious, almond milk not as nutritious as dairy milk. Almond milk contains added vitamin D, proteins and calcium to strengthen its nutritional similarities to dairy milk. However, almond milk contains calories fewer than dairy milk at 1.55 grams of proteins to 8.22 grams; the carbohydrate content is fewer as well at 1.52 grams of carbs to 12.18 grams. The Reference Daily Intake, abbreviated as RDI, shows vitamin E content is 49% in almond milk and 0% in dairy milk. In terms of the Reference Daily Intake, almond milk ranks higher than dairy milk in several minerals. Just to note, almond milk is naturally laden with a variety of vitamins and minerals. However, just like soy milk, the phytic acid in almonds inhibits the absorption of zinc, iron and magnesium. It is also not suitable as a substitute for breastmilk because it is lacking in many nutrients.

Because of its low-calorie characteristic, almond milk is a good milk alternative for those looking to control their weight. Sugar-free almond milk is also a good choice for diabetics and people who are on a low-carb diet because it contains only 0.6% of carbs as opposed to cow milk which has 5% carbs. Studies done by observation show consumption of almond products is linked to the reduced risk of heart disease. Consuming 66 grams of almond product including almond milk, daily for six weeks can reduceLDL cholesterol by 6% and reduces triglycerides by 14%. These changes in blood lipid profiles are very significant in heart health.

From an ecological aspect, almond milk requires a large amount of freshwater to harvest almonds each year. It is estimated that one almond tree utilizes approximately a gallon of water to grow a single almond. However, despite the intensive usage of freshwater, almond milk gives off the lowest gas emission to the environment compared to other milk alternatives. Almond milk is the only tree-based milk alternative with leaves which can consume carbon dioxide from the atmosphere. Thus, in terms of greenhouse gas emissions, almond milk is the most environmentally sustainable milk alternative as every 200ml glass of almond milk results in 0.14kg of carbon dioxide.

Rice Milk

Rice milk is a milk alternative that is derived from rice. Due to commercial purposes, rice milk is mostly made of brown rice. The procedure of making rice milk is to cook the rice and blend it with water. The mixture is then strained using a nut milk bag, cheesecloth or a napkin. Due to the fact that it is made from rice, rice milk contains a higher amount of carbohydrates compared to other milk alternatives, making the beverage naturally sweet. Each 100 grams of rice milk contains approximately 47 calories, 1 gram of fat, 9 grams of carbs, 0.3 grams of protein and vitamins A, C and D. It also contains minerals such as sodium and potassium. Although rice milk is ubiquitous and cheap, it is the most available milk alternative. The down side of rice milk is that it has less nutritional benefits as compared to the other milk alternatives.

From ecological aspect, rice milk has a negative environmental impact since the plant is a water hog plant. Though it does not consume as much as it takes to produce dairy milk it consumes more water compared to other milk alternatives. Another down side to rice milk is that the field where rice is harvested often has bacteria breeding in the water which releases methane to the atmosphere. Thus, rice milk is not a sustainable milk alternative as it produces more greenhouse gases compared to the other milk alternatives and the fertilizers used during harvest result in freshwater pollutions.

Oat Milk

Oat milk is a plant derived milk alternative produced from oat grains. Oat milk is derived by mixing the oat grains, blending them in water, then straining them through a cheesecloth. Naturally, oat milk isn’t as nutritious as whole grain oat and is less nutritious when compared to other milk alternatives. Similar to almond milk, oat milk is enriched with minerals and nutrients such as calcium, vitamins A and D, iron and potassium. Oat milk is a unique milk alternative like rice milk, it is free from allergens that are mainly found in dairy and other milk alternatives. Oat milk is favourable to people who have dietary restrictions. A cup of 240 ml of unsweetened oat milk contains about 120 calories, 3 grams of protein, 5 grams of fat, 16 grams of carbs, vitamin b12, vitamin A, potassium and iron minerals.

Ecologically, oat milk produces little gas emissions. Every 200ml glass of oat milk is responsible for approximately 0.18kg of carbon dioxide, it is a little over the amount of carbon dioxide almond milk produces but much less compared to soy milk. Oat milk also does not require a lot of water to grow like almond milk and in terms of the size of land, oats uses about 80% less land compared to dairy milk.

Coconut milk

Coconut milk is a milk alternative extracted from coconuts. It contains a high amount of coconut oil which is considered as healthy fat. People often choose this alternative because it aids in weight loss. Coconut milk also contains antioxidants that are rich in both vitamins C and E. The antioxidants help to neutralize harmful compounds found in bodies like tumor growth. In general, coconut milk has a positive impact on the environment since the growth of coconuts does not require pesticides or insecticides. It is not the most sustainable milk alternative because it produces higher gas emissions than almond and oat milk.

Hemp Milk

Hemp milk is made from whole hemp seeds and is known to be rich in healthy fats, proteins and vital minerals. It lacks lactose, gluten and soy which makes it favorable to people with dietary issues. Hemp milk contains 83 calories, 1.3 grams of carbs, 4.7 grams of protein, 7.5 grams of fat and minerals such as iron and calcium (Pramaullayko, 2019). Most of the fats in the hemp milk are unsaturated. Compared to dairy milk, Hemp milk has fewer calories, less proteins and carbs which are well balanced for a person’s dietary requirements. Hemp milk is one of the best plant dairy milk alternatives since it has fewer environmental impacts. The hemp is harvested in small quantities and is only available to grow in the Northern hemisphere. It is considered more environmentally friendly as it is not a monoculture operation like other milk alternatives. Hemp is known to have benefits to the soil as well as it produces fewer greenhouse gases emissions. The hemp plant is also one of the favorable dairy milk alternatives since it requires very little pesticides. When compared to the amount of pesticides required to produce dairy feeds and dairy animals, hemp plants require substantially less.

Cashew Milk

Cashew milk is a milk alternative made from cashews and water. It has various vitamins, minerals and related fats which are beneficial to the human body. Cashew milk is often used as a replacement to cow’s milk in cooking recipes. In terms of nutritional value, cashew milk contains 25 grams of calories, 2 grams of fat, 1 gram of fat, and no fiber. Like other milk alternatives, cashew milk is fortified with calcium and vitamin D.

The fats found in cashew milk are highly nutritious and can boost heart health, eye health and blood sugar control. Cashews are rich in antioxidants like lutein and zeaxanthin; these compounds can prevent cellular damages in the eyes. Research has found that people with high lutein and zeaxanthin have a low risk of cataracts, which is an eye problems during old age. It improves blood sugar control because it contains anacardic acid that stimulates the blood sugar levels in muscle cells. Like other milk alternatives, cashew milk is lactose-free, thus it can be beneficial to people who have diabetes. It also boosts the immune system in the human body; the milk derived from cashews isloaded with antioxidants and zinc, two components which are essential in boosting the immune system in the human body.  

Unlike rice milk, cashew does not contain compounds that could pollute the environment it grows. It produces more gas emissions than almond milk, but still significantly less than dairy milk. Although cashew milk is considered environmentally friendly, it is not the most sustainable milk alternative.

Environmental Impacts of Cow's Milk vs Alternative Milk

Cow's Milk Environmental Impacts

The production of cow's milk needs large amounts of resources to be expended. The average cow needs to be fed over 24 pounds of hay every day, assuming that the hay has at least 88% dry matter content. In order to grow enough hay to sustain a large dairy farm with hundreds of cows over a long period of time, thousands of litres of water need to be expended. 4-5 cubic inches of water is needed to grow a single ton of hay. Overall, it is estimated that almost 16, 000L of water is needed for every kilogram of cow. A single cow only needs 10 gallons of water a day to function. The high water footprint is the result of the large water requirement for fertilizer production, irrigation, beef processing, and diluting runoff water from feed crops. Furthermore, there is a large land requirement for grazing cows.

A single cow generally needs half a hectare of grazing land . Often, this land is made usable by cow farmer by clear cutting forest land in order to make the land suitable for grazing. This means that establishing a dairy farm results in the release of CO2 into the atmosphere. Millions of tonnes of CO2 and other GHGs have been released into the environment as a result of transforming forested land into dairy farm land. The removal of forest land also results in the loss of biodiversity. It is estimated that 2/3 of all distinct species live in forests. Many of these species rely heavily on the forest ecosystem and are unable to survive following the transformation of forest into other forms of land such as pasture land. Moreover, forested land are much better than pastures at purifying water. This is because root structures that exist within forests has the ability to retain water much better than pastures. This means that the production of pastures indirectly results in the pollution of water systems.

Dairy farms also have a high electricity requirement to function. A single dairy cow requires over five kWh of electricity every week in order to support water heating, waste handling, lighting, ventilation, and milk cooling in the cow milk production process. Over 20% of the electricity is used in the water cooling process because after milking, stored milk needs to be cooled from 37˚C to 4˚C and maintained at the temperature of 4˚C in order to keep the milk at its highest quality. To put into perspective, the total electricity cost of managing a dairy farm of 40 dairy cows is approximately equal to an entire U.S. home . Massive amounts of fertilizer is also expended to produce non-organic milk which consumes energy and robs the ground of nutrients that could otherwise be used for other forms of agriculture or landscape . Additionally, dairy farms create major externalities in the form of GHG emissions. It is estimated that a single dairy cow emits 330 grams of methane daily . It is important to consider that compared to carbon dioxide, methane is more potent in trapping heat. In a five year time frame, methane is able to trap almost 100 times more heat than carbon dioxide in the atmosphere (one green planet article).

Milk Alternatives Environmental Impacts

Visualization of the different environmental impacts of milk.

Research has shown that dairy milk has a significantly higher environmental footprint than rice milk, soy milk, oat milk, and almond milk in terms of CO2 emissions, land use, and water use . Rice milk, soy milk, and oat milk each have a carbon footprint that is approximately three times smaller than dairy milk, while the carbon footprint of almond milk is over 4 times smaller. Any milk alternative produces at least three times less greenhouse gas emissions . For water usage, producing rice milk and soy milk has approximately half of the water requirement of cow milk. Oat milk does not even need one-tenth of the water that cow milk needs and soy milk does not even need one-twentieth of the water that cow milk needs. Still, the biggest difference in the environmental impact of cow milk vs alternative milk lies in the difference in land use. Producing cow milk requires 11 times more land than oat milk, 13 times more land than soy milk, 18 times more land than almond milk, and a staggering 30 times more land than rice milk.

Comparing the different types of alternative milk, rice milk and almond milk are considered to be more environmentally damaging (though they are still significantly more eco-friendly than cow milk). Almond milk has a higher water usage requirement than other milk alternatives and it requires over a gallon to produce one almond. Soy milk, on the other hand, is known to have large land requirements compared to other milk alternatives. However, there are efforts being made to make rice and soy production more eco-friendly .The alternative milks with the smallest environmental impact are coconut milk, pea protein milk, and hemp milk, which all require smaller amounts of CO2, land, and water compared to dairy milk and even other alternative milks .

Overall, milk alternatives are more environmentally friendly than cow milk. However, cow milk is still a staple in many North American households despite a shift in demand of milk towards milk alternatives. In terms of environmental sustainability, it is absolutely better for the environment if households transition to using any type of alternative milk over cow milk.

Case Study - Canada

Global milk consumption and production rates in 2013.

The trends of milk consumption are greatly varied dependent upon the different countries around the world in regard to the various environments, cultures and diets observed. Due to the higher temperatures of some tropical regions, there is an increased difficulty in preservation processes which then requires immediate consumption of milk in order to prevent spoiling. This could lead to a general decrease in milk products or a shift from liquid milk to more fermented milk products.

The largest component of the dairy market is consisting of liquid milk which is consistently rising at a steady state. In considering milk production at a global scale, the European Union (EU) was the number one producer of cows milk in 2019 with the manufacturing of 522 million metric tons^[24]. This rate had increased by 25 metric tons since the year 2015. In order to produce this considerable amount of milk, 23 million dairy cows were used.

Though there is a general decrease in consumption for tropical regions, India is the worlds leading consumer for milk worldwide at 77.7 million tons as of 2019, closely followed by the European Union (EU). The drastic rate is due to the dietary practices being heavily comprised of various milk forms of milk products such as paneer and ghee or yogurt. The trends of consumption have been rising at a constant rate in India for over a decade.

The general consumption rate is higher of that in more developed countries than that of developing nations, but that gap is decreasing. This is largely due to shift to a higher quality of life with urbanization and incomes rising. This trend can be observed in nations that are very heavily populated particularly in Asia, such as in China.

Although there is a steady increase in the production of milk worldwide, in Canada, a decrease in milk consumption can be observed. In 2018, the consumption record had reached an all time low of approximately 65.9 liters per capita which was more than a 20 liter decrease per capita in comparison to the statistics collected in 2004. This trend is closely related to that of the consumption of pork and beef as the intake of red meats have decreased in Canada.

This decline in consumption is largely in part due to the rising number of people who choose to live vegetarian and/or vegan lifestyles^[23] with there being 2.3 million vegetarian and 850 000 vegan Canadians as recorded in 2018. With more citizens becoming more environmentally conscious due to raised awareness for global issues such as that of climate change and animal welfare, increased numbers of people have switched to a healthier and more sustainable lifestyle. The decline resulted in an increase in demand for more milk substitutes to be on the market due to the healthier lifestyle choices made by consumers. In considering the past 40 years, there s an increase in higher fat containing milk products to be substituted for those with lower fat content which also supports the claim of healthier goals of the general Canadian population.

It can also be observed that as the Canadian population ages, there is often a switch to healthier fat and dairy free options in order to maintain a more suitable diet. The elderly society have found alternative options in order to meet the daily intakes of calcium and proteins through methods such as supplements. The demographics of Canada is largely made up of elderly citizens or baby boomers that make up approximately 5 million people who have either eliminated milk altogether from their diets or have switched to largely popular plant-based alternatives such as almond or rice milk.

Another cause for the trend in decreased dairy consumption in Canada could be in relation to the diverse population and different ethnicities present within the county. With a constant flow of immigrant into Canada, there are various dietary practices being followed. There are several nations around the world that do not incorporate or are not heavily dependent upon dairy in their lifestyle. Some communities may perceive milk and its products to be seen as a luxury. These culinary traditions are practiced when people migrate into Canada which also in turn decreases the rate of dairy consumption.

Although the worldwide trends of dairy consumption may follow a general increase, Canada follows an opposite direction as milk consumption decreases. This is largely in part due to Canadian citizens becoming more environmentally and health conscious which leads to milk alternatives being largely pursued. With the increased awareness about animal and environmental issues, more citizens are making the shift to veganism which in return increases the consumption of pant-based alternatives. The demographic of the Canadian population being largely composed of immigrants and elderly who follow various non-dairy based diets also contribute to the decrease in milk consumption and increase in milk alternative products being available and consumed by society,

Conclusion

Accordingly, the most sustainable milk alternative options are pea protein milk, coconut milk, and hemp milk due to CO2, land, and water requirements compared to other alternative options. However, even the more environmentally damaging types of alternative milk are much more environmentally friendly compared to cow milk. The amount of water, land, and GHG emissions required to grow, feed, and maintain a cow farm are extremely high. This is because the environmental impact of a cow farm includes the deforestation caused when creating pasture land, the water needed to feed cows and grow hay, the methane emitted by cows, and the electricity required to run a dairy farm.