What is Icelandic Skyr yogurt ?

Skyr is an Icelandic cultured dairy product. It has the consistency of strained yogurt. According to MS Iceland Dairies (the principal producer of the modern-day skyr with the “Original Icelandic Skyr Cultures”), which is a cooperative organisation that includes over 700 of Iceland’s family-run dairy farms and other milk producers across the country, the Vikings first introduced Skyr to Iceland when they settled in the country some 1,100 years ago 1). Since then skyr has been a part of Icelandic cuisine for over a thousand years. It is traditionally served cold with milk and a topping of sugar.

Furthermore, according to many Icelanders and Icelandic skyr producers, the milk for skyr should be made by Icelandic cows and the skyr itself produced in Iceland using the original skyr cultures. Skyr, however, is also made in various other countries.

Traditionally, skyr is made with raw milk; however, modern skyr is made with pasteurized skimmed milk. A small portion of skyr is added to the warm milk, to introduce the right bacteria, such as Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Rennet is sometimes added as well, and the milk is left to coagulate. The skyr is then strained through fabric to remove the whey and the milk solids retained 2).

Skyr has a slightly sour dairy flavor, with a hint of residual sweetness. Commercial Icelandic manufacturers of skyr have added flavors such as vanilla, berries, etc. common to yogurt to the final product, to increase its appeal.

Skyr production:

  • Milk is separated from the cream
  • Skimmed milk is pasteurized
  • The pasteurized milk is fermented using a skyr culture for over eight hours. The skyr culture contains special yogurt cultures and a small amount of rennet. Because rennet is used it’s considered a cheese and not a yogurt.
  • The fermented milk is then filtered
  • Additional steps may add such things as flavoring e.g. Madagascar bourbon vanilla, fruits, agave nectar, cane sugar, etc.

Icelandic yogurt skyr nutrition facts

The nutrition content of skyr yogurt varies depending on the country of origin, brands, the types of milk used and other added ingredients. Generally, skyr is very similar to your plain yogurt in terms of protein, calories, carbohydrate, calcium, fat, minerals and vitamins content. These nutrients can vary depending on your favorite yogurt. So always check its packaging to learn more.

Skyr, like most yogurts are gluten-free, with some exceptions. In fact, milk and most cheeses are also naturally gluten-free foods, as are dairy ingredients, such as whey protein.

Gluten, a protein, is naturally found in certain grains, including wheat, rye, barley and combinations of these grains. As a result, foods made from these grains such as pasta, bread and cereals contain gluten. Foods from other food groups are gluten-free, as long as they don’t have added ingredients that contain any of those gluten-containing grains.

Table 1. Icelandic style Skyr yogurt

Ingredients: PASTEURIZED SKIM MILK, ORGANIC AGAVE NECTAR, MADAGASCAR BOURBON VANILLA, LIVE ACTIVE CULTURES, LIVE ACTIVE CULTURES: S. THERMOPHILUS, L. DELBRUECKII SUBSP. BULGARICUS, B. LACTIS, L. ACIDOPHILUS, L. DELBRUECKII SUBSP. LACTIS.

[Source: United States Department of Agriculture Agricultural Research Service 3)]

Table 2. Icelandic style Skyr strained-yogurt

Ingredients: PASTEURIZED LOWFAT MILK, CANE SUGAR, BLUEBERRIES, FRUIT PECTIN, LIVE ACTIVE CULTURES. LIVE CULTURES: B. LACTIS, L. ACIDOPHILUS, L. DELBRUECKII SUBSP. BULGARICUS, L. DELBRUECKII SUBSP. LACTIS, S. THERMOPHILUS

[Source: United States Department of Agriculture Agricultural Research Service 4)]

Table 3. Plain yogurt (non skyr yogurt)

Ingredients: PASTEURIZED JERSEY MILK, LIVE ACTIVE CULTURES, LIVE ACTIVE CULTURES: L. ACIDOPHILIS, BIFIDOBACTERIUM LONGUM, S. THERMOPHILIUS. L. BULGARICUS

[Source: United States Department of Agriculture Agricultural Research Service 5)]

Table 4. Plain yogurt (skim milk)

[Source: United States Department of Agriculture Agricultural Research Service 6)]

Table 5. Greek yogurt (plain whole milk)

Note: While the process for making both types of yogurt starts the same, Greek yogurt is made when regular yogurt is strained to remove the liquid whey. This results in a thicker, creamier, tarter yogurt 7).

[Source: United States Department of Agriculture Agricultural Research Service 8)]

What is yogurt

Yogurt (also spelled “yoghurt” or “yoghourt”) is considered by most regulatory agencies worldwide to be a fermented milk product that provides digested lactose and specifically defined, viable bacterial strains, typically Streptococcus thermophilus and Lactobacillus bulgaricus. It is a source of several essential nutrients, including protein, calcium, potassium, phosphorus, and vitamins B2 and B12 9).

Yogurt is an ancient food that has gone by many names over the millennia: katyk (Armenia), dahi (India), zabadi (Egypt), mast (Iran), leben raib (Saudi Arabia), laban (Iraq and Lebanon), roba (Sudan), iogurte (Brazil), cuajada (Spain), coalhada (Portugal), dovga (Azerbaijan), and matsoni (Georgia, Russia, and Japan). It is believed that milk products were incorporated into the human diet around 10 000–5000 BC, with the domestication of milk-producing animals (cows, sheep, and goats, as well as yaks, horses, buffalo, and camels) 10). However, milk spoiled easily, making it difficult to use. At that time, herdsmen in the Middle East carried milk in bags made of intestinal gut. It was discovered that contact with intestinal juices caused the milk to curdle and sour, preserving it and allowing for conservation of a dairy product for extended periods of time 11). For millennia, making yogurt was the only known safe method for preserving milk, other than drying it.

The word “yogurt” is believed to have come from the Turkish word “yoğurmak,” which means to thicken, coagulate, or curdle 12). While references to the health-promoting properties of yogurt date back to 6000 BC in Indian Ayurvedic scripts, it was not until 1905, when a Bulgarian medical student, Stamen Grigorov, discovered Bacillus bulgaricus (now Lactobacillus bulgaricus), a lactic acid bacteria that is still used in yogurt cultures today. Based on Grigorov’s findings, in 1909, the Russian Nobel laureate, Yllia Metchnikoff, from the Pasteur Institute in Paris, suggested that lactobacilli in yogurt were associated with longevity in the Bulgarian peasant population 13). In the beginning of the 20th century, yogurt became known for its health benefits and was sold in pharmacies as a medicine.

Yogurt today

Today, yogurt is typically milk that has been fermented and acidified with viable and well-defined bacteria, creating a thickened, often flavored, product with an extended shelf life. You can now find many varieties of yogurt in your dairy aisle, including low-fat yogurt, fat-free yogurt, Greek yogurt, Icelandic style (Skyr), Australian style and others. Since yogurt is made from milk, it contains many of the same nutrients, just in different amounts – especially when it comes to the various styles and brands of yogurt 14). Yogurt contains essential nutrients and is a vehicle for fortification (added probiotics, fibers, vitamins, and minerals). It is also easily modified by sweeteners, fruits, and flavors to affect consistency and aroma. Yogurt can also be produced from rice, soy, or nuts.

  • Animal-based Yogurt: Yogurt made from the milk of animals, such as cows, goats, sheep, camels, and buffalo.
  • Plant-based or non-dairy yogurt: Yogurt made from soy, coconut, nuts, rice or other plant foods. Note that not all plant-based yogurts undergo fermentation so they may not contain live bacteria. Plant-based yogurts may be lower in protein, calcium, and other nutrients unless they are fortified, so check the Nutrition Facts label if these nutrients are important in your diet.
  • Greek yogurt, also called “strained yogurt” or “yogurt cheese”: Yogurt that is strained to remove the whey portion, resulting in a thicker consistency than unstrained yogurt while preserving yogurt’s distinctive, sour taste.
  • Probiotic: Refers to foods, beverages, and supplements containing specific strains of live bacteria or microbiota. Food manufacturers may add additional probiotic strains for perceived health benefits. However, the exact amount of probiotics and strain of bacteria that yield a beneficial health effect will vary among individuals and is not well-researched.
  • CFUs or colony forming units: The number of living bacteria per gram. This is an indication of how many live bacteria are present in the yogurt at the time of manufacture. Yogurt typically contains at least 1,000,000, or 106 CFUs, which is the minimum needed to display a “Live and Active Cultures” seal on the packaging. This minimum number is the standard provided because it is expected that some bacteria will be destroyed when passing through the digestive tract and exposed to stomach acid. Though food manufacturers often promote the health benefits of multiple strains of bacteria and a high amount of CFUs, with some products offering billions of CFUs, research does not support these claims.

The active cultures in yogurt can help aid in the digestion of lactose. Individuals with lactose intolerance who cannot tolerate dairy products may be able to eat some yogurt because of its lower concentration of lactose. Fermentation by the bacteria breaks down lactose to lactic acid. Another option may be plant-based yogurts, which do not contain lactose. Check the package for the additional benefits provided by your favorite yogurt. These may vary depending on the type of culture in the yogurt.

Yogurt is made when heated milk is combined with bacteria, specifically Lactobacillus bulgaricus and Streptococcus thermophilus, and left to sit for 3–8 hours at a warm temperature (110-115°F). Additional types of lactobacilli and bifidobacteria may be added. Both bacterial strains must remain active in the final product (with at least 10 million bacteria/g, according to CODEX 2003) 15). The bacteria convert the sugar in milk, called lactose, to lactic acid, which thickens the milk and develops its distinctive tart flavor. The process to which prepasteurized skimmed milk is submitted, before it is turned into yogurt, is responsible for changes in carbohydrates, proteins, and lipids. It yields an acidic flavor and a product with an improved appearance, taste, consistency, and digestibility. When milk lactose is used as the fermentation substrate, lactic acid and a series of other compounds are formed, contributing to its aroma. As a consequence of a decrease in pH, the development of undesirable microorganisms is delayed, the calcium and phosphorus present in milk are converted into their soluble form, and the majority of proteins, now calcium free, are better digested by proteolytic enzymes, which enhances its digestibility and overall bioavailability 16).

Other bacterial strains, such as Lactobacillus acidophilus and Bifidobacterium bifidus, are often added for potential health benefits. When yogurt is consumed daily, there may be diminished growth of pathogens, which is ultimately beneficial to the human gut 17). The protein content of some yogurts, such as Greek yogurt, is modified by concentrating or adding protein to provide twice the amount present in regular yogurt products. Calcium and vitamin D are also added to some products, adding nutritional value for populations with a high incidence of lactose intolerance or a low intake of dairy foods.

The types of yogurt consumed today are influenced by local traditions or correspond to certain lifestyles. In Eastern Europe and Asia, people consume milk that has undergone alcoholic fermentation by combining bacteria and yeasts (e.g., Kefir, Koumis); in Germany and Spain, yogurt is typically heat-treated to kill the bacteria; and in other countries, various probiotics and/or prebiotics are added to the mix.

Probiotics and health

Yogurt offers several important nutrients including protein and calcium. However, much of the research on yogurt’s health benefits centers on its live bacterial content, which is also present in other fermented foods like kefir, kimchi, and sauerkraut 18). Currently, there is a gap between the point where the biomedical science ends (with the publication of a paper in a scientific journal) and the point where the business begins (with the claim for a health benefit). It has been proposed that a lower number of some bacterial strains in the body may influence risk of certain disease conditions including obesity, type 2 diabetes, irritable bowel syndrome, and chronic inflammatory diseases such as Crohn’s disease, ulcerative colitis, and rheumatoid arthritis 19), 20). A plant-based diet is associated with supporting a diverse and probably healthier gut microbiota more than a diet low in fruits and vegetables and high in meat 21) and yogurt consumption may also help to increase microbiota diversity in the gut 22). It is also well-established fact that the biological effects of probiotics are strain specific. Stig Bengmark 23) has made this very clear in his statement that the (genetic) difference between one probiotic bacterium and the other is larger than the difference between a man and a goldfish. The success (or failure) of one strain cannot be extrapolated to another strain (or strains). The strain-specific benefits of probiotics thus emphasises the need for proper strain identification 24).

Epidemiological research on specific health effects of yogurt is still limited but a few studies suggest a benefit. In a study following three large cohorts for up to 20 years that included 120,877 men and women free of obesity and chronic diseases at baseline, yogurt consumption appeared to protect from weight gain 25). The authors suggested that changes in colonic bacteria from eating the yogurt may have influenced weight changes. Daily yogurt intake may also protect against heart disease and type 2 diabetes 26), 27), 28).

A number of beneficial effects of probiotics dealing with gut health have been evaluated in Cochrane reviews. These meta-analyses have demonstrated the effect of probiotics on the prevention and treatment of antibiotic-associated diarrhoea 29), necrotising enterocolitis 30) and  in prevention of traveller’s diarrhoea 31).

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