Yoghurt, kefir, skyr, curd cheese and buttermilk: a critical comparison

The world of dairy products is rich in varieties, each with its own characteristics. Many people prefer dairy products such as yoghurt, kefir, skyr, curd cheese and buttermilk for their health benefits. Not only are they rich in protein, vitamins and minerals, but they can also be used in many different ways.

How dairy products are made and how they differ

Yoghurt, kefir, skyr, curd cheese and buttermilk are fermented dairy products made using different processes and cultures. Fermentation is a natural process in which micro-organisms, such as bacteria and yeasts, convert milk constituents through fermentation.

Fermented dairy products stay in the gut longer than pure milk, which can help improve digestibility. As well as being popular for their taste, they also offer nutritional benefits. For example, recent research suggests that kefir may have an anti-cancer effect.

Yoghurt: Pasteurised milk is fermented with special lactic acid bacteria. This process usually takes several hours to days and results in a creamy consistency and slightly tart flavour. As well as plain yoghurt, there is fruit yoghurt, drinking yoghurt and tzatziki (made from yoghurt, cucumber, olive oil and garlic).

Kefir: This more complex product is made by fermenting milk with kefir grains, which contain a mixture of lactic acid bacteria and yeast. These grains are added to the milk and the fermentation process usually takes 24 hours. The result is a viscous, sour milk product with a low carbon dioxide content and probiotic properties. Depending on how it is made, kefir contains between 0.1 and 0.6 per cent alcohol (rarely up to 2 per cent), which can be equivalent to the alcohol content of alcohol-free beer! Kefir should therefore not be given to children.

Skyr is an Icelandic product traditionally made from skimmed milk. Skyr is more like curd cheese than yoghurt and has a high protein content. It is fermented with special strains of bacteria, often based on yoghurt cultures, which gives it a mild flavour. Skyr contains three times more lactic acid bacteria than yoghurt and is an alternative for people who are sensitive to dairy products.

Quark or curd cheese is a fresh dairy product made from pasteurised milk with the addition of rennet and other milk cultures. After coagulation, the whey is separated, resulting in a creamy, soft cheese. This process usually takes several hours. Curd cheese is high in protein and can be used in a variety of ways, in both sweet and savoury dishes.

Buttermilk is a by-product of butter production. It is low in fat and slightly sour. It is fermented by special strains of bacteria that give it a refreshing flavour. Buttermilk can also be used as an ingredient in many recipes.

Health benefits of dairy products

Probiotic properties: A common benefit of most of these products is their content of probiotics, beneficial bacteria that can promote digestive health. Both yoghurt and kefir are particularly rich in lactic acid bacteria, which can support the gut microbiome and boost the immune system.

Nutrient content: All of the above dairy products contain important vitamins and minerals. Yoghurt and kefir are good sources of calcium, which is important for strong bones and teeth. Skyr and curd are particularly popular with athletes because of their high protein content, which can help build muscle.

Digestive properties: Another positive aspect is that it helps with digestion. Many people report having fewer digestive problems after consuming these products, especially probiotic kefir.

A critical look at the disadvantages and risks of dairy products

Lactose intolerance: The lactose in dairy products is a major problem for some people. While it is well tolerated by many people, it is difficult to digest for those with lactose intolerance. While lactose-free alternatives are available, they may not provide the same probiotic benefits.

High in sugar and artificial flavourings: Another concern is the sugar content of many yoghurt brands, especially flavoured varieties. Consumers should be aware of whether their products contain added sugar, as excessive sugar consumption has been linked to a number of health risks. Additives such as artificial flavourings are a common problem. Many commercially available products are often highly processed and contain additional sweeteners to enhance flavour.

Allergies: These products are not suitable for people with milk allergies. Milk allergies can cause severe reactions and require the avoidance of all dairy products.

Cholesterol in dairy products: Yoghurt, kefir, skyr, curd cheese and buttermilk generally contain relatively little cholesterol. Full-fat yoghurt contains about 10-20 mg of cholesterol per 100 g, low-fat yoghurt less. Kefir has similar levels, although the cholesterol content varies according to the fat content. Skyr and curd are high in protein and low in fat and cholesterol, usually less than 5 mg per 100 g. Buttermilk is also low in cholesterol and is a low-fat alternative to other dairy products.

Other harmful substances: Despite their health benefits, dairy products may contain preservatives or other harmful substances. One possible risk is the use of antibiotics and hormones in dairy farming. Residues of these substances can be found in finished dairy products, raising concerns about long-term health. Such residues may be more common in countries with less stringent animal husbandry regulations.

What are the vegan alternatives to dairy?

Awareness of vegan diets and lifestyles is growing, leading to demand for plant-based alternatives to animal-based dairy products. There are now many options that are similar in taste and consistency to the products mentioned above.

Plant-based yoghurt: This is made from soy, coconut or almond milk. These products are often fortified with probiotics, have a similar consistency to traditional yoghurt and are also lactose-free.

Coconut kefir: Instead of using dairy kefir, coconut milk can be used to make vegan kefir. The fermentation process is similar to regular kefir, resulting in a refreshing, probiotic drink.

Soy or almond curd: A vegan alternative to curd are products made from soy or almonds, which have a similar consistency and can be used in many recipes.

Cashew buttermilk: This can also be made from cashews or other nuts that are soaked and then pureed. It contains healthy fats and is a great ingredient for smoothies and baked goods.

Yoghurt, kefir, skyr, curd or buttermilk: the choice is yours

Yoghurt, kefir, skyr, curd cheese and buttermilk offer many health benefits, particularly due to their probiotic and nutrient content. However, consumers should also be aware of potential drawbacks such as lactose intolerance and high sugar content. The growing number of plant-based alternatives offers vegans an excellent opportunity to enjoy the benefits of fermented products. Ultimately, choosing the right dairy product depends on individual needs and preferences.

© "Yoghurt, kefir, skyr, curd cheese and buttermilk: a critical comparison". An article by Izabel Comati, 12/2024. Image credit: Quark dessert with strawberries, CC0 (Public Domain Licence).