Which Milk Should You Drink?

Milk consumption varies considerably across the world, but in the US, dairy milk consumption is in a decline. Non-dairy milk alternatives, on the other hand, are now present in 39% of homes. The variety of non-dairy milk alternatives, like almond, soy, and oat, is also increasing. But are these alternatives better for both human and planetary health? Or is it all greenwashing: the use of deceptive advertising to appear more environmentally friendly?  

Dairy Milk & Human Health 

Dairy milk is renowned for its calcium content, delivering almost one third of our daily calcium requirement. It also provides protein, carbohydrates, electrolytes, phosphorus, iodine, riboflavin, and Vitamin B12. Milk helps to keep bones, teeth, skin, and vision healthy, promotes normal brain development, and has been linked to normal immune system function. Whey, a protein component in milk, has been increasingly used for its benefits in muscle growth, and this growing global market is now estimated at $9.4 billion USD. 

Milk is often demonized in the media as causing obesity, type 2 diabetes, and cardiovascular disease. However, milk and dairy product intake may actually help to reduce childhood obesity. Having 200-300ml of milk per day has not been shown to increase cardiovascular disease risk and may in fact reduce the risk of hypertension and stroke. Evidence also suggests that dairy milk may not increase the risk of type 2 diabetes. Furthermore, milk may also have a protective effect against certain cancers, including colorectal and breast cancer, although the evidence for breast cancer is less conclusive. 

However, there are important caveats to the benefits of milk for human health. The amount and type of dairy milk is important to consider, with moderation as part of a balanced diet being essential for human health. Excessive consumption of milk - especially if containing high saturated fats - can cause weight gain, increased blood cholesterol, and increase the risk of cardiovascular disease. 

Dairy Milk & Planetary Health 

Global demand for milk and dairy products continues to rise, with approximately 270 million dairy cows worldwide. Methane is a greenhouse gas commonly associated with cows, but can also be created by burning fossil fuels, and is 28 times more potent than carbon dioxide in its global warming effect. When compared to non-dairy milk alternatives, cow’s milk produces three times more greenhouse gas emissions. 

With more and more dairy cows required to meet human demand, we also continue to unsustainably use the Earth’s land—70 percent of which is already exploited by human activity. Cow milk alone needs approximately ten times as much land than non-dairy milk alternatives require. Furthermore, access to fresh water is already difficult, with only 1% of the Earth’s fresh water accessible to humans. There is then the issue of inequitable distribution of fresh water to the human population, with 1.6 billion people lacking safe drinking water. Despite this, we are increasingly producing dairy milk, which becomes 85-90% water once it reaches consumers and requires between two and twenty times more fresh water than non-dairy milk alternatives. Therefore, while dairy milk may have several benefits for human health, it has severe consequences for planetary health. 

Non-Dairy Milk & Human Health 

There are many reasons to have non-dairy milk, including lactose intolerance, milk allergy, veganism, and simply personal choice. One of the key issues is comparing individual nutritional benefits of dairy and non-dairy milks. For example, non-dairy milks generally contain less fat, protein, sodium, and calories. They are often fortified with calcium to reach dairy milk levels, but they are not commonly fortified with vitamin D and vitamin B12. Furthermore, many non-dairy milks are flavored, with added sugars also complicating the nutritional picture. 

Almond milk contains more calcium than dairy milk but contains less protein, folate, and vitamin B12. Vitamin D levels in oat milk are dependent on the brand purchased, but it also has less sugar and fat compared to cow’s milk. Coconut milk has more magnesium and iron, but a higher saturated fat content and less calcium. Soy milk, in contrast, has similar protein to cow’s milk, with less sugar and fat overall, and a higher unsaturated fat content, but it also has less phosphorus and vitamin D. Therefore, from a nutritional perspective, the combination of different nutritional components in different types of milk can make it understandably confusing to decide which milk to drink. 

Non-dairy milk consumption as part of an otherwise nutritionally balanced diet may help to avoid nutritional deficiencies. Taste is also particularly important, as consumers have varying preferences. Further research is required to better understand the long-term effects that non-dairy milk alternatives may have on human health. 

Non-Dairy Milk & Planetary Health 

Non-dairy milk alternatives are often described as being more sustainable. Evidence suggests that non-dairy milks require less land, less fresh water, and produce less eutrophication (when nutrients accumulate in a water environment, causing excessive algae growth and resulting in detrimental impacts on animal and plant biodiversity). They also create only one third of the carbon emissions that dairy milk does and produce less methane. Oat milk is considered the most sustainable option in the media, requiring less fresh water than dairy milk, soy milk, and almond milk. 

However, while better for the planet than dairy milk, non-dairy milk remains imperfect. For example, nine different pesticide residues have been found in almonds, with five of these being toxic to bees, and 130 pints of water are required for one glass of almond milk. Animal cruelty has been previously associated with coconut milk, with monkeys being illegally and abusively trained to pick coconuts. Coconut famers are estimated to earn as low as $200 per year, in detriment to the United Nation’s Sustainable Development Goals which includes “No Poverty.” Furthermore, the high demand for soybeans – which is widely used as animal feed – contributes to global deforestation. 

Is there a straight answer? 

Perhaps not. Still, overall, the evidence suggests that while more nutritionally complete, dairy milk has adverse and unsustainable consequences on planetary health. In comparison, non-dairy milk alternatives offer some benefits for human health, and even more so for the Earth. Therefore, while imperfect, consuming non-dairy milk alternatives as part of a nutritionally balanced diet appears to be the most sensible option for both human and planetary health.