What's in a plant-based milk?

Minnesota: With 75% of the global population being lactose intolerant and concerns for the environment on the rise, plant-based milks have emerged as a viable alternative to dairy products in recent years. It's a global US$20 billion industry, with sales expected to more than double in the next decade.

Dairy-free alternatives make up the largest plant-based market segment in the US, with 2.9 billion US dollars in sales last year. The plant-based drinks made up close to 15% of the total milk dollar sales. Nearly half of all US households bought plant-based milks in 2023.

Yet in a recent study of 219 plant-based milk alternatives, scientists at the University of Minnesota's Nutrition Coordinating Centre found they offered fewer nutritional benefits than cow's milk. Including less calcium or vitamin D.

Very different carbon footprints of plant-based milks and dairy
As cattle-rearing is linked to deforestation and methane emissions, there are also environmental and climate implications to consuming dairy products.

The median per liter greenhouse gas emissions associated with soy, oat, almond, spelt, pea and coconut milks are 62-78% lower than those connected to cow's milk, the authors of a study titled Dairy and Plant-Based Milks: Implications for Nutrition and Planetary Health found.

But what type of milk is best for the planet and our bodies?
"It's a little difficult and nuanced to answer the question of which one is best," said Brent Kim, researcher at the Johns Hopkins Center for a Livable Future and one of the authors of the study.

"Do we mean the smallest climate change impact? Do we mean the most nutritious milk, the most affordable milk or maybe are we more concerned about how much fresh water was used to produce that milk? Or maybe how much agricultural land had to be occupied to produce that milk?"

What's clear is that plant-based foods have a much lower carbon footprint — that doesn't just mean CO2.

And Kim says that while packaging and transport account for some of those emissions, the vast majority are generated before the crops leave the farm.

Environmental trade-offs
But there are different environmental trade-offs when it comes to plant-based milks, too. While almond milk compares favorably to cow's milk when it comes to greenhouse gas emissions, it doesn't look so good if you factor in its water footprint. Almond milk is the most sold plant-based milk in the US, accounting for three quarters of overall sales.

Kim said one of the better options would be milk made from pea protein, citing lower greenhouse gas emissions and good protein levels.

"And if we're concerned about freshwater use, which we certainly should be, it had one of the smallest water footprints of all the different milks," he said, adding that soy milk also checked all of these boxes. While there were some studies showing that soy had a slightly higher climate impact compared to pea, he said there also had been more studies done on soy milk. So the verdict's still out.

However, milk made from pea protein isn't as widely available yet.

So which milk is best for our health?
With all the different brands and types on the market, is it even possible to say which one is best?

That's difficult, says Abby Johnson, associate director of the Nutrition Coordinating Center at the University of Minnesota in the School of Public Health and lead author of the study looking at over 200 different plant-based milks.

"There's a lot of variability. Every plant-based milk, it seems, is formulated differently," she said.

Dairy is considered a good source for three of five nutrients of concern identified in the 2020–2025 US Dietary Guidelines: calcium, potassium, and vitamin D.

The diet of the average American far exceeds the amount of protein that they need for a healthy diet, said Kim. But that extra dairy protein is important for some groups.

"Especially for growing children, especially in areas where people struggle to have a variety of food, dairy is really important because it provides a good amount of proteins," said Becky Ramsing, a public health nutritional professional, registered dietitian, and senior program officer at Johns Hopkins Center for a Livable Future.

"Oats are not necessarily a high protein food," she added. And don't be fooled to think almond milk was high in protein because it's made from nuts, either.

"The way that the milks are made, there's a lot of water added to that, so the protein content actually is very low," she said.

Word of advice: read the label!
"You can't just pick a plant-based milk off the shelf and assume that's going to fit one profile. Everyone is so different," said Ramsing. It's important to read the label to find out what's in the product.

Ramsing said she experienced that herself when she found out her favorite soy milk wasn't fortified with calcium. And you might be surprised to find out how much added sugar is in some of the milks.

Getting all the nutrients from milk and a healthy diet
One advantage of plant-based milks compared to cow's milk is extra fiber. Johnson says there are some plant-based milks that provide more than 10% of the daily value of fiber — while cow's milk has none.

On the other hand, cow's milk is rich in vitamin B2 or riboflavin which are important for cell growth and energy production; and the phosphorus that's important for our bones and teeth.

But you can still drink that type of plant-based milk if you get your nutrients elsewhere, says Johnson.

"Eat a diverse diet with lots of fruits and vegetables and you wouldn't have to worry about being deficient in either vitamin B2 or in phosphorus," she said.

"Plant-based milks can definitely be part of a healthy diet."