PLANT-BASED MILK ALTERNATIVES
Popular plant-based beverages used as alternatives to cow’s milk include almond, rice, oats and coconut “milk”. Health professionals (dietitians, nutritionists, medical doctors, community health nurses, and others who dispense dietary advice) should alert consumers to the fact that these beverages are processed grains, legumes, oil seeds and nuts mixed with water and sometimes fortified with macro- and micronutrients (e.g. calcium and vitamin B12). Plant-based beverages are fortified to mimic the nutritional composition of cow’s milk.
Plant-based beverages are, therefore, highly processed products compared to cow’s milk, which is a naturally rich and good source of essential nutrients. These include high-quality protein, a unique mixture of slow- and fast-digesting proteins 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 in excess of 400 different proteins), all in a unique food matrix. This extends the health benefits of cow’s milk beyond the effects of individual nutrients.
Individuals and certain populations exclude milk and dairy from their diets for a variety of reasons. Present-day consumers are more aware of health and nutritional benefits, and the environmental impact of the foods that they purchase and consume. Excessive exposure to ever-changing food choices and the advertisements accompanying them may confuse and overwhelm consumers. This confusion can cause consumers to discard whole food groups in their search for healthy, pure, environmentally friendly foods.
Consumers often list the following reasons for avoiding milk and dairy intake:
- Cow’s milk protein allergy (CMPA)
- Lactose (the sugar naturally occurring in milk) intolerance, which is generally self-diagnosed and not confirmed by laboratory testing
- Saturated fat content
- Cultural beliefs or preferences
- Dietary preferences, i.e. vegan, flexitarian, or paleo diet
- Beliefs such as prevention of cruelty to animals or environmental degradation (this could lead to exclusion of all foods derived from animals)
Unfortunately, the names of many plant-based alternatives to milk include the word “milk”, which may lead the public to believe that they are buying and drinking products that are similar to cow’s milk. They believe that they are reaping the same nutritional benefits from plant-based beverages, as those found in cow’s milk. This is usually not the case, as illustrated below.
Cow’s milk and plant-based dairy alternatives differ considerably with regard to the amount and quality of protein present per 100 ml. Plant-based beverages contain very little protein – usually only 1 g per cup, compared to 8 g in a cup (250 ml) of cow’s milk.
Protein quality has a notable effect on the nutritional quality of a dietary protein source. Cow’s milk is also naturally high in “complete” protein (providing all essential amino acids), whereas plant-based milk substitutes contain mostly “incomplete” protein. 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
|
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%) consists of the naturally occurring milk sugar, lactose, while plant-based beverages have different contents of different types of carbohydrates, for example unsweetened soy milk contains only 2,8% carbohydrate, while rice milk has a high 11,5% carbohydrate content. Plant-based beverages are mostly sweetened with added sucrose to make them more palatable, with the carbohydrate and sugar contents varying considerably, e.g. by 3 to 11 g of sugar/100 g.
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 of calcium in a food or beverage and its bioavailability and absorbability are all vitally important for human health. Lactose, casein, and phosphopeptides are all found in cow’s milk and they all promote calcium absorption. The human gut can rapidly absorb 30% to 35% of the calcium in cow’s milk.
Plant-based beverages may well contain equal amounts of calcium. However, they are all fortified with either calcium tri-phosphates or calcium carbonate and may contain chemical compounds that inhibit calcium absorption, e.g. oxalates (nuts and beans) and phytates (beans, seeds, nuts, soy isolates and high-fibre whole grains, e.g. oats). Oxalates and phytates bind to calcium and form insoluble compounds, which are difficult to absorb. Regrettably, the human body only absorbs about 5% of the calcium in plant foods. Consequently, individuals who depend on plant sources for their calcium intake, have to eat very large quantities of such 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 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 it differs substantially in its nutrient composition. However, a plant-based diet together with cow’s milk and dairy can be highly beneficial and deserves to be considered as a solution to providing a sustainable diet for the growing human population.