The moo-ve to plant-based milks

Plant-based milks (PBMs) are becoming more and more popular. And with new kid on the block – potato milk – recently hitting the headlines, we thought it was time to take a deep dive into plant-based milks.
 
A Canadian study showed that over the period 2004 to 2015 there was a significant decrease (70.2% to 56.1%) in plain dairy milk consumers, along with an increase in PBM from 1.8% to 3.0%.

People are making the shift to PBMs for all sorts of reasons: health, cultural, animal welfare, planetary health, dairy allergies, lactose intolerance, and dietary preference.

Cafes are embracing the move – you can readily get a soy, almond, oat, rice, or coconut latte just about anywhere. In fact, it’s often easier to get a plant-based latte than a trim milk option.

Being nosey (and a little peeved I can no longer get my trim cappuccino at several of my favourite haunts) I asked a few baristas why this was the case. The most common response was lack of storage space due to the increasing demand for plant-based options.
 
But how do these PBMs stack up against each other, and against cow’s milk?
 
Let’s start by looking at the effects on the planet. Afterall, one of the big drivers in the switch to PBMs is planetary health. The easiest question to answer is how PBM compare to cow’s milk.

All PBMs are more environmentally friendly than cow’s milk. Cows take up a lot of land and need lots of water. It’s estimated that it takes about 9 times more land to make a glass of milk compared to PBMs.
 
Things get a little trickier when comparing the different PBMs. They all have pros and cons.

• Almonds use more water.
• Soy and oats use more land.
• Rice is also quite water-intensive and produces more greenhouse gases. Plus, when you flood the rice paddy, fertilisers can run off the land into water ways.

The new potato milk – Dug– is touted as the most sustainable on the market. But given all PBM are better for the environment than cow’s milk, making any switch will benefit planetary health.

You might also want to consider country of origin. As we searched through the different PBMs available in NZ, it was interesting to note that while many were made in NZ or Australia, some came from further afield. So, if you’re interested in food miles, you might want to check out the country of origin on the packaging.
 
The next big question is health. In terms of nutrients, how do PBMs compare to cow’s milk, and are some better than others?
 
Cow’s milk is a good source of a number of nutrients including protein, calcium, phosphorous, riboflavin, vitamin B12, and vitamin D. And contains no added sugar.

Because plant-based options are called ‘milk’, there’s concern many of us may switch to plant-based alternatives without considering the full impact on the nutrients in our diets.
 
Protein

More recent data points to an even greater slide in the popularity of plain dairy milk. This study noted while cow’s milk contributed 12.5% of protein amongst cow’s milk consumers, PBMs provided only 1.4% among PBM consumers. Other estimates have suggested that dairy milk contributes over 15% of protein to the diet in North American and European populations.
 
Cow’s milk contains around 3.3 g to 4.5 g protein per 100 g, with trim milk containing more than whole milk.

Soy milk contains 3.3 g per 100 g, making it the best alternative to cow’s milk. It contains about 5 times the amount of protein found in other plant-based milks.

A US study reported the lowest amounts protein in almond and rice milks. But for the milks we reviewed (see our Nutrition Resources), coconut was the lowest at 0.2 g per 100 g, with the other plant-based milks having anywhere between 0.2 g and 1.4 g per 100 g depending on what brand you go for. So, it’s worth checking the nutrition information panel (NIP).

We did find an almond milk that was marketed as a high protein – on closer inspection while this contained 4% almonds, it also contained 3.5% soy protein.
 

As well as considering protein content, protein quality is also worth a mention. Researchers looking at protein quality found cow’s milk was the winner, followed by soy. Rice milk protein scored the lowest (although there was no value for almond milk).
 
Energy

Soy milk is closest in energy content to cow’s milk. Of the milks we looked at, the unsweetened nut milks had the lowest energy content. This was similar to a US study which reported almond milks had the lowest energy content ranging from 50 to 105 kJ per 100 ml.
 
Fat

Whole cow’s milk contains around 3.1 to 3.5 g per 100 g of fat, and around two-thirds of this is saturated fat. As the name suggests, trim milk contains less fat – around 0.1 to 0.4 g per 100 g.

A Canadian study showed that plain dairy milk contributed 14.5% to saturated fat. In NZ the contribution of milk to saturated fat was 8% (although it should be noted while most of this group was cow’s milk, it did include small amounts plant-based milks).
 
Plant-based milks have a better fatty acid profile compared to cow’s milk, with one exception – coconut milk.

Coconut milk is made by diluting coconut cream (and sometimes adding sugar). Coconut has the highest amount of saturated fat, comparable to the amount found in whole cow’s milk.

On the other hand, almonds are an excellent source of unsaturated fatty acids, meaning almond milk has an excellent fat profile. But almond milks do differ. They can contain anywhere between 2% and 14% almonds. Most of the ones we looked at contained between 2.5% and 5% almonds. The average almond weighs 2 g, which means these 'almond' milks contain around one to two almonds per 100 ml.
 
Carbohydrate

The milks with the highest carbohydrate content are rice (9 - 10 g per 100 g) and oat (5 - 9.5 g per 100 g). Cow’s milk contains around 4.5 g of carbohydrate per 100 g. This is in the form of lactose. Some plant-based milks will have added sugar, so watch out for the sweetened versions.

One of the almond milks we examined had cane sugar as number 2 on the ingredient list – coming ahead of almonds!
 
Micronutrients

While cow’s milk is a great source of calcium, riboflavin, and vitamin B12, with useful amounts of vitamin D, plant-based milks are either naturally low or contain none of these nutrients. This makes it important to choose a fortified plant-based option.

While many we looked at were fortified with these nutrients – some only fortified with calcium, while others weren’t fortified at all – meaning they had low nutrient density. So, check out the NIP.

This lack of fortification is also seen when making homemade milks. And if most of your milk is from a barista coffee, you might want to check they are using a fortified milk.
 
Going back to our Canadian study, among dairy consumers, cow’s milk contributed over 30% of daily calcium and vitamin B12 intakes, and 20% of riboflavin. Among plant-based milk consumers, plant-based beverages contributed similar percentages – 27.5% calcium, 25.1% B12, and 16.3% riboflavin.

This suggests, if fortified, plant-based milks can make substantial contributions to the nutrients in our diets.
 
What about bioavailability?

Lactose in cow’s milk enhances the bioavailability of vitamins and minerals, and one of the milk proteins, casein, enhances the bioavailability of calcium.

One study showed that absorption of calcium from soy milk fortified with tricalcium phosphate was 25% lower than from cow’s milk. However, a later study showed that the fortificant was important. Soy milk fortified with calcium carbonate had similar absorption to cow’s milk. So, it’s worth checking out the fortificant.
 
A word of caution – sedimentation. This can be a problem when fluids are fortified with calcium. One study showed that fortified beverages provided only 31% of calcium when left unshaken, rising to 59% when shaken. This study also showed that only 2 of the 9 fortified soy beverages met the labelled calcium content when shaken. This settling and poor solubility means we may be missing out on substantial amount of calcium.
 
Benefits of PBMs

So far, we’ve looked at how PBMs stack up against cow’s milk. But different plant-based milks have beneficial nutrients not found in cow’s milk. These nutrients reflect the plant food from which they’re extracted.

For example, oat milk has beta-glucans known for their hypocholesterolaemic effects – although the dose to reduce cholesterol would mean drinking 750 ml per day. Almond milk contains vitamin E and has a good fatty acid profile. Hemp milk contains one of the essential fatty acids, alpha-linolenic acid.

Hard on the wallet

One last factor to consider is cost. There’s been lots of chat around rising food prices. PBM tend to be 2 to 3 times the price of cow’s milk. This can be a significant barrier.
 
Bottom Line

So, whether cow’s milk or a plant-based milk is your tipple – there’s loads of choice. If you are using PBM as a replacement for cow’s milk, then fortified soy milk is the best switch.