The demand for plant-based alternatives to cow’s milk has increased significantly in recent years. However, the extent to which health benefits can be expected from milk alternatives made from soy, oats, almonds or rice remains controversial.
Soy, rice and oat milk are often touted as healthy and sustainable alternatives to cow’s milk and dairy products. However, studies indicate a lower nutrient quality. An Italian research team from the University of Padua has now investigated what differences actually exist in the nutritional content of cow’s milk and plant-based milk alternatives.
Comparative analysis of nutrient content
Various brands of almond, oat, rice, coconut and soy-based drinks were used for a comparative analysis with goat and cow milk, the researchers report in the specialist magazine “npj Science of Food”.
The focus was on the total protein content, the amino acids, the fat content or the various fatty acids and the minerals contained.
Differences in protein content and amino acid profile
According to the researchers, soy drinks had the highest total protein content (3.47 percent), followed by cow’s milk (3.42 percent) and goat’s milk (3.25 percent). The content of the other milk alternatives was significantly lower.
Looking at the individual amino acids, both types of animal milk also had a higher content per unit volume of all essential amino acids than soy-based drinks, with the exception of phenylalanine, the researchers report.
However, the content of other amino acids such as arginine, serine or aspartic acid in soy drinks is on average even higher than in animal milk. However, the protein content and the amino acid profile were generally subject to significantly greater fluctuations in the plant-based milk alternatives, explains the team.
According to the researchers, this also indicates a lack of standardization in the production of plant-based milk alternatives, which could lead to uncertainties regarding the nutritional content for consumers.
The researchers also emphasize that the bioavailability of the amino acids and the ability of the human intestine to absorb these amino acids must also be taken into account in the evaluation.
Little protein in rice and almond milk
Here, cow’s milk performs significantly better than all plant-based alternatives, although soy at least comes close to the values of cow’s milk. According to experts, the bioavailability of proteins in milk alternatives based on rice or almonds is particularly poor.
Overall, soy drinks seem to be the best plant-based alternative to cow’s milk when it comes to proteins. However, the researchers point out that 14 percent of people with a cow’s milk allergy also have an allergy to soy proteins, so soy drinks cannot be a substitute for them.
Comparison of fat content and fatty acids
As expected, whole cow’s milk (3.55 percent) and goat’s whole milk (3.72 percent) had the highest fat content, with only relatively small fluctuations between the individual products, the researchers report. The lowest values were found for oat-based drinks (0.37 percent).
Among the plant-based milk alternatives, almond-based drinks had the highest fat content (1.99 percent), and plant-based products mainly contained long-chain fatty acids (with the exception of coconut milk, which has a high proportion of medium-chain fatty acids), the research team continued.
In cow’s milk, on the other hand, there is a combination of long-chain and medium-chain fatty acids and, compared to plant-based products, a much larger proportion of the lipid content is made up of so-called saturated fatty acids, which are considered to be rather unhealthy compared to unsaturated fatty acids.
With their higher content of unsaturated and polyunsaturated fatty acids, the plant-based alternatives (except coconut) seem to offer clear advantages here. According to the researchers, they are well suited as a source of healthy lipids, with soy-based drinks scoring points with a particularly high content of healthy fatty acids.
Oat milk also contains a lot of unsaturated and polyunsaturated fatty acids and it is known that oat derivatives can lower triglycerides and unhealthy LDL cholesterol due to the abundance of soluble fiber and antioxidants, which can have additional positive effects on health researchers.
In contrast to all other plant-based milk alternatives, coconut-based drinks have a similar lipid composition to that of animal milk.
Sugar, salt and carbohydrates
Cow’s milk generally contains lactose, a milk sugar that makes up the majority of the carbohydrate content. In milk alternatives, however, the carbohydrates are contained in the form of starch, for example.
According to the researchers, rice-based drinks had the highest carbohydrate content, followed by almond-based drinks and oat-based drinks. The high carbohydrate content of the almond drinks was entirely unexpected, as almonds contain only a few carbohydrates.
The researchers also found that additives are often used to influence the taste, color and consistency of plant-based milk alternatives. 73 percent of the products tested contained added salt, 23 percent contained added sugar and 67 percent contained at least one additive other than salt, sugar and water.
In particular, the added sugar and salt should be assessed critically from a health perspective, as sugar increases the risk of cardiovascular disease, obesity and diabetes, and too much salt can increase blood pressure and the risk of kidney disease.
What are the differences in minerals?
According to the researchers, all minerals in animal milk were generally present in higher concentrations than in the plant-based alternatives, with the exception of magnesium. The content of some milk alternatives is similar to that of animal milk.
Rice-based drinks were overall the drinks with the lowest mineral content, as magnesium and potassium, for example, were completely missing and some other minerals were only contained in small amounts, the team continued.
According to the researchers, soy-based drinks had the highest mineral content among the plant-based milk alternatives. However, all plant-based products lacked the iodine contained in cow’s milk and goat’s milk, meaning that an adequate iodine supply could be jeopardized in the long term.
According to the researchers, further efforts are needed to promote iodine enrichment in plant-based milk alternatives.
Soy drinks the best milk alternative?
Overall, the plant-based milk alternatives show a lower content of total protein, lipids, amino acids and minerals compared to goat and cow milk, although soy-based drinks are an exception, the team reports.
The soy drinks have a comparable protein content to cow’s milk, a similar composition of amino acids and a high mineral content, the researchers continue. It also contains more healthy fatty acids.
- Cow’s milk or soy milk – which is healthier?
Although the plant-based products are marketed as nutritious milk alternatives with health benefits, their nutritional content is often severely limited and their carbohydrate and sugar content is elevated, experts point out.
If dairy products are completely replaced by plant-based alternatives, this could lead to a deficiency of certain minerals and corresponding health problems, especially if the implementation takes place without taking one’s own nutritional needs into account. (fp)