Milk is one of the most versatile products available out there which can be used in many different forms. Whether you prefer it in your morning coffee, poured over cereal for breakfast, in cooking or baking recipes, or blended in a protein shake, milk is a product that is present in many daily routines and probably has its dedicated spot in your fridge.

However, especially in the last decade, the choice between cow milk and plant-based alternatives has gained significant traction. With increasing concerns about sustainability, animal welfare and health, many people are turning their heads to plant-based alternatives as replacements to moo juice. You might have seen articles showing that plant-based milks provide a lot more environmental benefits compared to dairy milks. But does science really agree with this statement?

Comparing plant-based options to cow’s milk isn’t always straightforward. Different studies report varying numbers, and not all methods are standardised. Some blog posts might just provide you with a single number from a single study or life cycle assessment.

In this blog post, we aim to provide a clear and scientifically sound comparison between plant and dairy milk, highlighting key environmental and nutritional differences while acknowledging the complexities of these comparisons.

Environmental Impact: A Breakdown by Milk Type

The environmental impact of our consumption is central to the Conscious Quokka, including the impact of drinking milk. The sustainability of different milk types varies significantly based on multiple factors, including water consumption, land use, greenhouse gas (GHG) emissions, and energy usage. Below, we break these down by milk type. It is important to note that environmental impact estimates can vary significantly depending on the study and methodology used. The values presented here are approximations based on life cycle assessments (LCA) from multiple sources.

Cow’s Milk

• Water Consumption: Requires approximately 1,000 liters of water per liter of milk due to the water needs of dairy cows, feed crops, and processing.
• Land Use: High, as dairy farming requires pasture and cropland to grow animal feed.
• GHG Emissions: High, with around 3 kg CO2-equivalent per liter of milk, mainly from methane emissions from cows.
• Energy Usage: Moderate to high, as dairy farming and milk processing require significant energy input.

Soy Milk

• Water Consumption: Moderate, using about 297 liters per liter of soy milk.
• Land Use: Low to moderate, and this can depend on the way the soy is farmed and the efficiency of the process.
• GHG Emissions: 9 kg CO2-equivalent per liter, significantly lower than cow’s milk.
• Energy Usage: Moderate, as soy processing involves soaking, grinding, and fortification.

Oat Milk

• Water Consumption: Low to moderate, requiring about 48 liters per liter of oat milk.
• Land Use: Low, as oats grow efficiently in many temperate regions.
• GHG Emissions: 9 kg CO2-equivalent per liter, similar to soy milk.
• Energy Usage: Moderate, with processing steps including enzyme treatment to break down starches.

Almond Milk

• Water Consumption: High, with approximately 371 liters per liter of almond milk, mostly due to irrigation in drought-prone regions like California.
• Land Use: Low to moderate, but concerns about pesticide use exist.
• GHG Emissions: 7 kg CO2-equivalent per liter, one of the lowest among plant-based milks.
• Energy Usage: Moderate, mainly for almond processing and packaging.

Coconut Milk

• Water Consumption: Low, as coconut trees require minimal irrigation.
• Land Use: Moderate, though concerns about deforestation and monoculture farming exist.
• GHG Emissions: 4 kg CO2-equivalent per liter, one of the lowest among milk types.
• Energy Usage: Moderate, as coconut milk requires extensive processing.

Pea Milk

• Water Consumption: Low, with significantly less water than soy or almond milk.
• Land Use: Low, as peas grow in diverse climates and enrich soil with nitrogen.
• GHG Emissions: 8 kg CO2-equivalent per liter, making it a sustainable option.
• Energy Usage: Moderate, due to processing steps like protein extraction and fortification.

Nutritional Comparison

Environmental impact is one aspect to think about when consuming, but we also have to think about the nutritional value of the products that we consume. We grew up in a world where the health benefits of cow milk were often praised, especially to grow “strong and healthy bones” due to its calcium content. Indeed, dairy milk is known for having essential nutrients, including calcium, protein, immune-boosting vitamin A, vitamin D, zinc and vitamin B12. Plant-based milks on the other hand are often fortified with these vitamins and minerals, for example through adding vitamin B12.

Nutrient content of milks varies depending on the brand, processing methods, and fortification levels. The values provided below are approximate and based on commonly available nutritional data.

Macronutrients

• Protein: Cow’s milk provides 3g of protein per 100ml, while soy milk is the closest alternative (3-3.5g per 100ml). Other plant-based milks (oat, almond, coconut) contain only 0.2-0.8g per 100ml.
• Fat: Dairy milk contains 3-8g of fat per 100ml, depending on whether it’s whole, skim, or reduced-fat. Many plant-based milks add vegetable oils (e.g., canola, sunflower) to mimic the mouthfeel of dairy.
• Carbohydrates & Sugar: Oat milk has the highest natural carbohydrate content due to oat starches, typically around 6-10g per 100ml. Many plant-based milks contain added sugars, so it’s essential to check labels.

Micronutrients

• Calcium & Vitamin D: Dairy milk is naturally high in calcium and fortified with vitamin D. Most plant-based milks are fortified to match these levels.
• Vitamin B12: Present in dairy milk but lacking in plant-based options unless fortified.
• Additives: Many plant-based milks contain thickeners, stabilisers, and emulsifiers (e.g., gellan gum, carrageenan, lecithin) to improve texture and shelf life.

Water Content & Processing

Most plant-based milks consist primarily of water (85-98%), with a small proportion of plant material and added ingredients like oils, stabilisers, and sweeteners. Dairy milk, in contrast, is a whole food with fewer processing steps.

Variations and Methodological Considerations

As we mentioned, comparing different milk types is challenging due to variability in study methodologies. Some aspects that might differ per study are:

• Differences in agricultural practices: Environmental impacts depend on farming methods, such as organic vs. conventional farming.
• Geographic variation: A study in one region (e.g., Europe) may not be applicable elsewhere due to climate, water availability, and land use.
• Nutrient bioavailability: Fortified nutrients in plant-based milks may not be absorbed as efficiently as those naturally present in dairy.
• Life cycle assessments (LCA): Studies assessing environmental impact differ in scope—some include transportation, while others focus only on production.

Conclusion

Just like everything else regarding sustainability, milk choice is not straightforward either. Dairy milk is nutritionally dense but has a higher environmental footprint. Soy and pea milk are the most sustainable protein-rich plant-based options. Oat milk is a strong contender for sustainability and taste, while almond and coconut milks have pros and cons depending on water use and land impact.

To make an informed choice, consider nutritional needs, sustainability concerns, and ingredient transparency. What is also important is to read product labels carefully: check if the fortified nutrients and additives align with your individual health goals. You can also pay attention to where the ingredients are sourced to get an indication of the nutritional content. Another alternative is to make plant-based milk yourself from e.g. dried soybeans or oats, which reduces the carbon footprint as the water did not have to be transported, but reduces its shelf-life.

So, we cannot conclude whether one type of milk is better than the other, as this depends on personal values and dietary needs. Hopefully this post helps you in deciding what type of milk works best for you!

Sources

Khanpit, V., Viswanathan, S., & Hinrichsen, O. (2024). Environmental impact of animal milk vs plant-based milks: Critical review. Journal of Cleaner Production, 141703. https://doi.org/10.1016/j.jclepro.2024.141703

Berardy, A. J., Rubín-García, M., & Sabaté, J. (2022). A scoping review of the environmental impacts and nutrient composition of plant-based milks. Advances in Nutrition, 13(6), 2559-2572. https://doi.org/10.1093/advances/nmac098

Ramsing, R., Santo, R., Kim, B.F. et al. Dairy and Plant-Based Milks: Implications for Nutrition and Planetary Health. Current Environmental Health Reports 10, 291–302 (2023). https://doi.org/10.1007/s40572-023-00400-z

 

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