PLANT-BASED MILK ALTERNATIVES
Popular plant-based beverages used as alternatives to cow’s milk include almond, rice, oat and coconut ‘milk’. However, these beverages are made from grain, legume, seed or nut extracts mixed with water and so are not the same as cow’s milk, although they may be fortified with macro- and micronutrients (e.g. .
Plant-based beverages are therefore highly processed products compared with cow’s milk, which is naturally a rich source of essential nutrients. These include high-quality protein and important minerals (calcium) and vitamins (vitamin B12 in particular). Cow’s milk contains a variety of natural bioactive components (e.g. more than 400 specific fatty acids and more than 400 different proteins), all in a unique food matrix. This extends the health benefits of cow’s milk beyond the effects of individual nutrients.
Unfortunately, the labels of many plant-based beverages include the word ‘milk’, which may lead consumers to believe that they are consuming products that are similar to cow’s milk, with the same nutritional benefits. This is usually not the case.
Consumers often list the following reasons for avoiding milk and dairy intake:
- cow’s milk protein allergy
- lactose intolerance (often self-diagnosed and not confirmed by laboratory testing)
- saturated fat content
- cultural beliefs or preferences
- dietary preferences, such as following a vegan, flexitarian or paleo diet
- preventing cruelty to animals or environmental degradation (this could lead to exclusion of all foods derived from animals).
Consumers are increasingly aware of the health and nutritional effects and environmental impact of the foods they buy. However, excessive exposure to ever-changing food choices and accompanying marketing may become confusing and overwhelming, to such an extent that whole food groups are discarded in the search for healthy, ‘pure’ and environmentally friendly foods.
Cow’s milk and plant-based dairy alternatives differ considerably with regard to their protein content. Plant-based beverages contain very little protein: usually only about 1 g per cup (250 ml), compared with 8 g protein in a cup of cow’s milk.
Cow’s milk is also naturally high in ‘complete’ protein (providing all essential amino acids), whereas plant-based milk substitutes contain mostly ‘incomplete’ protein. Protein quality has a notable effect on the nutritional quality of a dietary protein source, and owing to the ratio of essential amino acids in animal-derived protein, the protein in cow’s milk has a higher bioavailability than that of plant-based milk substitutes. For example, the nutritive value of soy protein is limited by its lower content of methionine and cysteine. Therefore, when plant-based protein is used, more total protein must be consumed for the body to get enough of the amino acids it needs. Refer to the table on nutrient comparisons for details:
Product | Energy | Protein | Total |
Cow’s milk full-cream | 645 | 8.3 | 11.8 |
Cow’s milk fat free | 365 | 8.3 | 12.0 |
Soy milk | 496 | 7.8 | 8.3 |
Soy milk | 394 | 7.7 | 5.5 |
Oat milk | 591 | 2.8 | 19.4 |
Oat milk | 385 | 2.0 | 12.5 |
Almond | 298 | 1.3 | 9.2 |
Almond | 258 | 1.4 | 4.6 |
Coconut | 934 | 1.7 | 11.8 |
Coconut | 1134 | 2.3 | 7.4 |
Rice milk | 570 | 0.4 | 28.0 |
*Source: Milk SA report on plant-based imitation dairy beverages sold in the South African retail market. September 2020.
Note: Most sampled plant-based beverages contain stabilisers and are fortified. It is advisable to read the labels of each brand to determine the specific fortification that is applicable. At present there is no regulation stipulating the nutritional requirement for plant-based imitation dairy beverages.
|
per cup
(250 ml) |
Energy
(kJ) |
Protein
(g) |
Total
carbohydrates (g) |
Of which added
sugar (g) |
Fat (g) |
Calcium
(mg) |
Sodium
(mg) |
|
Cow’s milk full-cream |
645 |
8,3 |
11,8 |
0,0 |
8,3 |
298 |
123 |
|
Cow’s milk fat free |
365 |
8,3 |
12,0 |
0,0 |
0,3 |
308 |
130 |
|
Soy milk
(sweetened)
|
496 |
7,8 |
8,3 |
6,0 |
5,4 |
139 |
168 |
|
Soy milk
(unsweetened) |
394 |
7,7 |
5,5 |
1,6 |
5,0 |
230 |
97 |
|
Oats milk
(sweetened) |
591 |
2,8 |
19,4 |
9,8 |
6,0 |
238
|
94 |
|
Oats milk
(unsweetened) |
385 |
2,0 |
12,5 |
2,3 |
3,8 |
265
|
133 |
|
Almond
milk (sweetened) |
298 |
1,3 |
9,2 |
9,3 |
3,1 |
321 |
135 |
|
Almond
milk (unsweetened) |
258 |
1,4 |
4,6 |
1,4 |
4,7 |
286 |
91 |
|
Coconut
milk (sweetened) |
934
|
1,7 |
11,8 |
8,2 |
19,2 |
316 |
71 |
|
Coconut
milk (unsweetened) |
1134 |
2,3 |
7,4 |
3,8 |
25,8 |
323 |
64 |
|
Rice milk
(unsweetened) |
570 |
0,4 |
28,0 |
13,6 |
3,0 |
280 |
71 |
*Source of the composition of plant-based beverages: Milk SA report on plant-based imitation dairy beverages sold in the South African retail market. September 2020.
Note: Most sampled plant-based beverages contain stabilisers and are fortified. It is advisable to read the labels of each brand to determine the specific fortification that is applicable. At present there is no regulation stipulating the nutritional requirement for plant-based imitation dairy beverages.
The carbohydrate content of cow’s milk (about 4.7%) comes from lactose, a type of sugar that occurs naturally in milk. In contrast, the carbohydrate content of plant-based beverages can differ considerably between products, and many are sweetened with added sucrose to make them tastier. For example, unsweetened soy milk contains only 2.8% carbohydrates, while rice milk has a high carbohydrate content (11.5%).
Milk is an excellent source of highly bioavailable calcium, of which we require 1 000 mg a day to ensure optimal bone strength during all life stages. The amount, bioavailability and absorbability of a product’s calcium are all important for human health. Lactose, casein and phosphopeptides found in cow’s milk promote calcium absorption. The human gut can rapidly absorb 30–35% of the calcium in cow’s milk.
Although plant-based beverages may contain equal amounts of calcium as cow’s milk, the products are fortified. This means either calcium triphosphate or calcium carbonate has been added to the product. In addition, plant-based beverages may contain chemical compounds that inhibit calcium absorption, e.g. oxalates (common in nuts and beans) and phytates (found in beans, seeds, nuts, soy isolates and high-fibre whole grains such as oats). Oxalates and phytates bind to calcium and form insoluble compounds, which are difficult to absorb (the human body only absorbs only about 5% of the calcium in plant foods). Consequently, individuals who have a mainly plant-based diet have to eat large quantities of calcium-containing plant foods to obtain sufficient calcium for their body’s requirements, or take supplements. The calcium in one glass (250 ml) of milk is equivalent to that in 23 almonds, two cups of cooked spinach, three cups of beans or seven cups of cooked broccoli.
Plant-based beverages should preferably not be used as complete milk replacements, because the products differ substantially in their nutrient composition. However, a plant-based diet together with cow’s milk and dairy can be beneficial and should be considered as a solution to providing a sustainable diet for the growing human population.