The earliest evidence of dairy milk consumption by humans’ dates back almost 9 000 years to modern-day Turkey, near the sea of Marmara, where Richard Evershed, a biogeochemist and his team from the University of Bristol, UK, found milk-fat residues on ancient potsherds, which dates from the dawn of animal domestication.
Theory has it that the early cows, sheep, and goats were domesticated around 10 000 to 12 000 years ago, mainly for meat and that milk consumption followed millennia later.
Interestingly, ancient genomic studies showed that these early animal farmers were lactose intolerant and that tolerance for milk only became common in Europe after the Bronze Age, 5,000 to 4,000 years ago.
These days shopping for milk offers a variety of choices, as dairy milk now shares the shelf with many non-dairy alternatives, in the form of plant-based milk.
Alternative milks:
Alternative milks can be categorized according to their plant base, such as:
- Grain – rice, quinoa, and oat milk.
- Fruit – banana milk.
- Legume – pea protein and soy milk.
- Nut – almond, walnut, cashew, and coconut milk.
- Seed – hemp, sesame, and flaxseed milk.
Alternative milks are offered in various options, such as in flavour (chocolate or vanilla for example) and in sweetness, (unsweetened or sweetened options), and fortification (some are fortified with added vitamins and minerals).
Many people turn to non-dairy milk because of an allergy or intolerance. However, all plant-based milks are not created equal, with significant differences not only in taste, but also in providing important nutrients such as protein, vitamins, and minerals.
Nutritional composition of dairy milk and plant-based milks:
The decline in dairy milk consumption in Western countries and the increasing number of new plant-based milks being introduced to the market and advertised as milk substitutes on shelves next to milk products, has prompted a comprehensive study in Switzerland to evaluate their nutritional composition compared to cow’s milk. The results of the study were published in the journal Frontiers in Nutrition in 2022. The analysis included two whole milk samples and 27 plant-based milk substitutes such as almond, cashew, coconut, hemp, oat, rice, soy, and spelt.
To add substance to the claim that not all plant-based milks are created equal, all but four of the samples contained added salt. Nine samples contained sugar or other sweeteners, 14 samples contained stabilizers, emulsifiers, and thickeners. All rice, oat, hemp, and spelt samples contained sunflower oil. Nine samples were supplemented with one or more vitamins and calcium. In four samples calcium in the form of red algae was added.
The nutritional composition of all the samples were analyzed in terms of macronutrients and micronutrients.
Macronutrients:
Macronutrients refer to a type of food required in large amounts in the diet. The three main types of macronutrients are protein, fat, and carbohydrates. These are the essential nutrients the body needs daily to remain healthy.
Protein: Protein is an essential macronutrient and is made from basic building blocks called amino acids. The body needs 20 different amino acids to function correctly, and these 20 amino acids combine in different ways to make proteins in your body. The body cannot make nine of the amino acids, known as essential amino acids, as they must come from the food you eat or drink.
Once digested, dietary protein is broken down into its individual amino acids, which are then absorbed into the blood stream and transported around the body. These amino acids are then used to make all the various proteins that the cells in the body need.
The highest protein content amongst the plant-based milks included in the Swiss study was soy milk (the closest to dairy milk), with rice milk having the lowest protein content. Protein content of oat- and coconut milk were also low, with cashew and almond milk slightly higher. The poor protein content correlates with lower concentrations of amino acids and a poorer ratio of essential amino acids (eAA) to non-essential amino acids (neAA). This results in a lower biological value of their proteins.
Fat: This most calorie-rich macronutrient breaks down into fatty acids (protein breaks down into amino acids) to provide the body with energy. Essential fatty acids are structural components the body can only obtain through food. Fat has many essential functions in the body, such as absorbing fat-soluble vitamins (including vitamins A, D, E, and K), it helps to create hormones, it supports healthy skin and hair, and is essential to brain health, as about 60% of the brain is composed of fat. It also makes food palatable, but the type of fat and amount of fat we consume need to be carefully considered.
The essential fatty acids are omega-6 and omega-3 and the daily intake in the correct ratio is vitally important. Mother’s milk has the perfect ratio of omega-6 to omega-3 at between 5:1 and 10:1. Research has shown that a skewed intake of too high a ratio of omega-6 to omega-3 can contribute to various illnesses. Results from the Swiss study indicate that the mean ratio of omega-6 to omega-3 fatty acids are relatively low in the cows milk and soy milk, compared with the other drinks, which were much higher in omega 6 content.
While cow’s milk contains some saturated fat, which may be less heart healthy than unsaturated fat, skim or nonfat milk offers a less fatty option.
Calculated values for the ratio of omega-6 to omega-3 fatty acids in different plant-based milks and cow’s milk:
| Product | Ranges in ratio of omega-6 to omega-3 |
| Almond milk (4 different products) | (127 to 235): 1 |
| Cashew milk (2 different products) | 78: 1 |
| Coconut milk (3 different products) | (11 to 18): 1 |
| Cow’s milk (2 different products) | (2 to 3): 1 |
| Hemp milk (1 product) | 30: 1 |
| Oat milk (4 different products | (84 to 105): 1 |
| Rice milk (5 different products) | (92 to 175): 1 |
| Soy milk (7 different products) | (7 to 8): 1 |
| Spelt milk (1 product) | 112: 1 |
Carbohydrates: The three main types of carbohydrates in food are sugars, starches, and fiber. Results from the Swiss study shows that dairy milk has the highest total carbohydrate concentration. The total carbohydrate contents of plant-based milks were high in the spelt, oat, and rice milks, while moderate in the cashew and coconut milk, and low in the hemp, soy, and almond drinks.
Plant-based milks contain sucrose and glucose as the main types of carbohydrates, while dairy milk’s sole source of carbohydrates is lactose.
| Product | Sucrose | Fructose | Glucose | Lactose | Starch |
| g kg-1 | g kg-1 | g kg-1 | g kg-1 | g kg-1 | |
| Almond milk | 12,5 | 0,01 | 0,1 | 0,4 | |
| Cashew milk | 3,6 | 0,0 | 0,3 | 19,1 | |
| Coconut milk | 16,0 | 0,0 | 3,1 | 8,6 | |
| Cow’s milk | 0,0 | 0,0 | 0,1 | 50,2 | 0,0 |
| Hemp milk | 1,35 | 0,0 | 0,3 | 14,4 | |
| Oat milk | 1.5 | 0,9 | 33,2 | 7,9 | |
| Rice milk | 2,3 | 0,8 | 24,6 | 20,5 | |
| Soy milk | 14,0 | 0,01 | 0,1 | 0,7 | |
| Spelt drink | 0,7 | 1,1 | 37,2 | 1,3 |
The unit g kg-1indicates the number of grams of substance (e.g. sucrose) per kilogram of mixture. 1 Kilogram is 1 000 grams.
Micronutrients:
Micronutrients refers to essential vitamins and minerals, which are chemical elements or substances that are required in trace amounts for normal growth and development.
- Vitamins: In the Swiss study, the cashew, rice, oat, and coconut milk contained low amounts of vitamins compared to other plant-based milks, while vitamins such as C, A, and K2 could only be detected in dairy milk. The soy milk had the highest levels of folic acid and vitamins B1, B2, B6, E, and D2 amongst the plant-based milks. All of the measured vitamins were detected in dairy milk, except for vitamin D2.
- Minerals and trace elements: All plant-based milks without fortification with vitamins and minerals had significantly lower calcium contents than dairy milk and contained lower amounts of phosphorus, zinc, sulfur iodine, potassium, and chloride. The cashew milk was high in copper, zinc, and selenium. The vitamin E content of plant-based milks was higher than dairy milk.
Processing methods also plays a role in the nutritional value of plant-based milk. For example, some of the nutritional value of nuts may be lost in their milk products due to processing methods that include high temperatures, grinding, and extracting food substances with water, while also removing fiber.
Conclusion:
Some people turn to non-dairy milk due to an allergy or intolerance to dairy products. Plant-based milks offer some other benefits as well, such as being lower in fat and sugar. Most plant-based milks have 37% to 75% less fat and also less sugar, as dairy milk contains lactose (milk sugar) at 12 grams per cup, compared to most plant-based milks having just one gram of carbohydrates, with less calories.
However, over the years dairy milk has been used for its high nutrient density and quality, especially for protein and calcium, as well as being a significantly richer source of micronutrients than plant-based milks.
Research has indicated that plant-based milks cannot be considered nutritionally equivalent to dairy milk. Complete replacement of milk with plant-based milks without adjusting the overall diet to overcome the nutritional gaps may result in deficiencies of some important nutrients in the long term.
References:
Comparison of nutritional composition between plant-based drinks and cow’s milk. Published 28 October 2022 in the journal Frontiers in Nutrition. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Should you switch to plant-based milk? Published 24 January 2022. UCLA Health. University of California. Los Angeles. USA. (www.uclahealth.org)
Cow milk vs alternative milk: What’s the best? Published 4 October 2023. Baylor College of Medicine. Medical school in Houston. Texas. USA. (www.bcm.edu)
Plant-based beverages vs cow’s milk. Published online. IFAS Extension. University of Florida. USA. (www.aninal.ifas.ufl.edu)
We still don’t know why humans started drinking cow’s milk. Published online. National Geographic. (www.nationalgeographic.com)
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