Nutritional differences between milk and plant-based drinks

Milk has been consumed for around 10,000 years. Milk and milk products are part of the everyday diet of many. Milk naturally contains essential nutrients like protein, calcium, potassium, phosphor, iodine and vitamins B2 and B12. In recent years, there has been increasing interest in beverages based on soy, hemp, coconut, oat, rice and nuts.  In an article published in the International Dairy Journal, Chalupa-Krebzdak et al. (2018) analyse the nutrient composition of milk compared to these drinks.

Summary | Milk naturally contains essential nutrients like protein, calcium, potassium, phosphor, iodine and vitamin B2 and B12. Research conducted by Chalupa-Krebzdak et al. (2018) shows that the nutrient composition of plant-based drinks varies considerably. Plant-based drinks contain half as much protein on average than milk (1). Additionally, the amount of vitamins and minerals and their absorption is less consistent (1). That is why these researchers have concluded that, from a nutritional perspective, plant-based drinks are not always a good alternative to milk (1).

Study characteristics

The study complemented previous research by analysing brand-to-brand variations present with plant-based drinks. Milk (skimmed, 1%, 2%, and whole milk with 3.25% fat) and 17 plant-based drinks (5 brands of soy, 3 brands of coconut, 1 brand of rice, 1 brand of hemp, 5 brands of almond, and 2 brands of cashew drinks) were compared in this additional study.

Results

The amount of macronutrients and calcium in milk (skimmed, 1%, 2%, and whole milk with 3.25% fat) and 17 plant-based drinks were compared in order to determine whether plant-based drinks provide a comparable amount of nutrients as milk and, consequently, can play a comparable role in the provision of nutrients.

Review comparing cow’s milk to various plant-based beverages that are positioned as milk alternatives

Protein

In the study, milk was determined to contain an average of 3.15-3.37 grams of protein/100 ml. The amount of protein in plant-based drinks varies considerably. Soy drinks contain an average of between 2.5 and 3.16 grams of protein/100 ml. By contrast, rice drinks contain an average of 0.28 grams of protein/100 ml. Extra protein is added to some plant-based drinks. One in five almond drinks, for example, contain added protein.

Energy

The amount of energy in milk varies based on the fat content. The amount of energy in the study ranged from 34 kcal per 100 ml for skimmed or fat-free milk to 61 kcal per 100 ml for whole (3.25% fat) milk. As for plant-based drinks, the study found that the energy level ranged from 12 to 92 kcal per 100 ml. When consuming milk, the intake of energy will vary less than when consuming various types of plant-based drinks. The differences among these drinks in terms of energy content is greater. The researchers also noted that a large proportion of energy in plant-based drinks originates from carbohydrates and sugars and this leads to a relatively higher Glycemic Index (GI).

Glycemic Index

GI makes it possible to classify carbohydrate-containing foods based on the speed of carbohydrate digestion and absorption postprandial. This index reflects the direct effect of carbohydrate intake on blood glucose levels two hours after the meal. (3) Since no GI information was available for the samples used in this study, the authors report the findings of Jeske et al., (2017), which show that plant-based drinks have higher GI values than milk. (4) Milk had a GI of 46.93, while the GI of the plant-based drinks varied from 47.53 to 99.96. Low (<55 GI) and medium (56-69 GI) foods are recommended, especially for those who want to better regulate their blood sugar levels.

Fat

Although there was no data available for the total breakdown of saturated and unsaturated fats for all the plant-based drinks in this study, the authors noted that the available data indicated a trend towards less saturated and more polyunsaturated fats. Replacing saturated fatty acids with polyunsaturated fatty acids has a positive effect on the LDL cholesterol level in the blood.

Calcium

Calcium is needed for the maintenance of normal bones. The level of calcium varies greatly among plant-based drinks. The reason is that plant-based drinks are not always enriched with calcium. The researchers also point out that various bioactive components present in plants that can impact the absorption of nutrients must be taken into consideration. (1) Phytic acid, for instance, which is found in many cereals and legumes, binds to a significant amount of calcium, causing reduced calcium bioavailability. (1)

Other nutrients

Milk naturally contains essential nutrients like protein, calcium, potassium, phosphor, iodine and vitamins B2 and B12. Plant-based drinks contain various nutrients not found in milk. These include soluble fibre in oat-based drinks, alpha linoleic acid in hemp-based drinks and vitamin E in almond-based drinks. The researchers noted that the amount of nutrients per product varies.

Conclusion

Milk is a natural source of protein, calcium, potassium, phosphor, iodine and vitamin B2 and B12. The nutrient composition of plant-based drinks varies considerably. Nonetheless, the researchers have concluded that, from a nutritional perspective, plant-based drinks are not a suitable alternative to cow’s milk.

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