Get your gut: what are probiotics?

 

What are probiotics? What do probiotics do? Probiotics and probiotic foods are supposed to support the good bacteria in our gut and promote our health in various ways. Yogurt, cheese or sauerkraut might not be on your everyday shopping list, but we’ll tell you why they should be!

Our intestines are home to countless bacteria – experts estimate that there are about 1.3 times as many bacteria as there are cells in our bodies.^[1] Every person has 100 to 200 different types of bacteria in their gut. Some species have a particularly positive effect on our health – others have a negative effect. The most important thing is that we promote a healthy environment, in which healthy gut bacteria can thrive, so that we can prevent dysbiosis in our guts.

This is because findings from science indicate that diseases such as irritable bowel syndrome, chronic inflammatory bowel diseases, allergies, obesity, diabetes and depression are linked to our gut bacteria.^[2] The good news is that you can do a lot to improve your gut bacteria by following a predominantly plant-based diet. In addition, you can incorporate certain natural probiotic foods into your diet – these are said to offer a particularly large number of health benefits.

Find out what exactly probiotic foods are, what do probiotics do – and become familiar with the eight most important natural probiotics. You should also know the benefits of probiotics and what to look out for when buying them – gain more insights in our article!

What are probiotics?

Probiotics are living organisms (bacteria) that are added to many foods. Once in the gut, they contribute to a well-functioning and happy gut microbiome. They absorb essential nutrients and fight infections.^{[6, 21]} 

Probiotics are normally produced when foods undergo natural fermentation. This is why they are found in yogurt, kefir and sauerkraut, for example. However, the process of fermentation is time-consuming – and is therefore often omitted in modern food production. As a result, many foods that are actually probiotic aren’t beneficial for your gut health.^[22]

To promote healthy gut bacteria, you should certainly include more probiotic foods in your diet.

Studies suggest that probiotics can improve lactose intolerance symptoms; reduce diarrhoea, constipation and flatulence; lower cancer-promoting enzymes; help with vaginitis; relieve food allergy symptoms; and have a beneficial effect on atopic dermatitis.^[4]

What are lactic acid bacteria?

Lactic acid bacteria are naturally found in our intestines, but also in milk, for example. They convert lactose into more digestible lactic acid, whereby milk coagulates and becomes thick (fermented). This process is used to produce sour milk products such as yogurt, kefir and cheese because pathogens cannot grow in this acidic environment. Lactic acid bacteria can therefore help to ward off harmful germs.^[4]

Probiotic yogurts only contain probiotic lactic acid bacteria at first – or these are added later, after the fermentation process. These lactic acid bacteria can pass through the stomach unharmed and settle in your intestine.^[5]

These probiotic bacteria then multiply in your intestine and get rid of any bad bacterial cultures present there. This is to promote healthy intestinal flora.^[6]

Did you know that you can only positively influence your gut flora if you regularly eat probiotic yogurts that are as fresh as possible and contain many living bacteria. Toward the end of the sell-by date, the number of probiotic germs can decrease.^[4]

What are resistant starches?

‘Resistant starch’ is the term used for starch and starch by-products. Resistant starch reaches the large intestine undigested, where it serves as a source of energy for the bacteria found there. It thus has physiological properties similar to dietary fibre:^[26]

• It improves gut health
• It increases the amount of stool you produce

The following foods contain resistant starches

Amount	Food	Resistant starches
1	Banana (unripe)	4.7 grammes
1/4 cup	Oats (uncooked)	4.4 grammes
1/4 cup	Frozen peas (cooked)	4.0 grammes
1/4 cup	White beans (cooked)	3.7 grammes
1/4 cup	Lentils (cooked)	2.5 grammes
3	Boiled potatoes (cooled)	2.4 grammes

What are probiotic foods?

The term ‘probiotic’ translates as ‘for life’. Foods are described as probiotic if they contain sufficient microorganisms and provide positive health effects in our gut.^[3] These microorganisms include, for example, lactic acid bacteria such as lactobacilli and bifidobacteria, but also certain yeast fungi.

How can I get probiotics naturally?

Generally, fermented foods – that is, foods produced by fermentation – contain natural probiotics. The following foods are commonly probiotic and can support your gut microbiome.

You can check the bacteria cultures in your gut and see if your gut flora is healthy or if there is an imbalance between good and bad bacteria. You do this by visiting your doctor or by taking a gut microbiome test. These are usually rather extensive and will tell you how to improve your gut health.

Foods that are fermented (that is, preserved by lactic acid fermentation) during their production contain particularly high levels of probiotic bacteria.

We have compiled a list of the healthiest natural probiotics for you.

1.     Yogurt

Natural yogurt is one of the best sources of probiotics. It can improve your intestinal flora and help with issues such as diarrhoea or constipation.^[10]

But yogurt also has a lot to offer in other ways: experts recommend that you should regularly consume dairy products like yogurt because they provide our bones with calcium and our muscles with high-quality protein.^[11] Studies suggest that natural yogurt may even prevent high blood pressure.^[12]

Did you know that some fruit yogurts usually contain a lot of sugar, so you should consider it more of a dessert? When buying, look for traditionally produced dairy products that have not been pasteurised. By the way, the same applies to vegan yogurts – only some products still contain lactic acid bacteria!

2.     Kefir

The traditional Turkish milk product is made from sheep’s, goat’s or cow’s milk. In addition to lactic acid bacteria, the kefir tuber is used for fermentation – namely, it contains both lactic acid bacteria and yeasts. This converts some of the milk sugar into lactic acid and some into alcohol and carbonic acid (but the alcohol content in fresh kefir is at most 0.5 to 2 per cent).

Like yogurt, kefir can improve bone density and help with digestive problems. Due to its high content of various vitamins, minerals and essential amino acids, kefir is said to have numerous other health benefits. These include, for example, an antimicrobial and anti-inflammatory effect and positive effects on sugar and fat metabolism.^[13]

Did you know that traditional kefir is almost lactose-free? This means that people with lactose intolerance can usually tolerate it well.^[14]

3.     Cheese

Living lactic acid bacteria are mainly found in Cheddar, Gruyère, Gouda, mozzarella and Parmesan cheeses. Generally speaking, the older the cheese, the more probiotic bacteria it contains.

However, it is important to note that living probiotic bacteria are only found in unpasteurised cheeses! They are killed during the heating process. So, pay attention to information on the packaging – this is where manufacturers indicate whether their products are heat-treated.^[15]

In addition to this healthy probiotic bacteria, cheese contains many proteins, vitamin A, vitamin B2 and calcium.

4.     Sauerkraut

Sauerkraut is produced by fermenting white or pointed cabbage. The cabbage is cut into vats, mashed, salted and stored in an airtight container. The lactic acid bacteria, which are usually already attached to the cabbage, convert the fructose also found in the cabbage into lactic and acetic acid. You can also add sauerkraut juice (brine) to achieve a quick and even fermentation.

After 10 to 14 days, the cabbage has fermented and is then called fresh cabbage. This sauerkraut contains many probiotic bacteria and is especially suitable for vegans.^[17] Sauerkraut also contains a lot of vitamin C and large amounts of dietary fibre, which aids your digestion.

Only fresh sauerkraut contains the lactic acid bacteria and vitamins. Pasteurised sauerkraut from a can or jar contains neither vitamins nor probiotic bacteria due to the heating process. Traditionally produced, fresh sauerkraut can be found in health organic stores, for example.

Did you know that, like sauerkraut, the traditional Korean dish kimchi is made from Chinese cabbage? During fermentation, the cabbage is mixed with other vegetables, fermented with various spices and fish sauce to gets its typical reddish colour. The probiotic food is considered one of the healthiest in the world.^[18]

5.     Gherkins

Gherkins (also called pickles) are prepared in a mixture of water, herbs, sugar and salt. The lactic acid bacteria sit on the cucumber skin and then produce lactic acid, which makes the cucumbers durable.^[19]

Due to their high content of probiotic lactic acid bacteria, gherkins contribute to optimal digestion. One study even suggests that gherkin water may relieve muscle cramps and prevent sore muscles.^[20] Another benefit is that gherkins contain hardly any calories and no fat.

6.     Apple vinegar

Apple cider vinegar is produced from apple juice with the help of yeasts and lactic acid bacteria. The microorganisms first ferment the juice into cider. The alcohol is then converted to acetic acid – whereby apple cider vinegar is produced.

Apple cider vinegar is said to have various positive effects on the body. For example, it is said to help with weight loss, lower blood sugar levels and reduce the risk of cardiovascular diseases. So far, however, no study has been able to clearly prove these effects.^[21] Nevertheless, apple cider vinegar contains probiotic bacteria as well as many vitamins, minerals, trace elements and enzymes that make it very healthy.

Buy high-quality, naturally cloudy organic apple cider vinegar that has not been filtered or pasteurised. This means that it still contains valuable microorganisms.

7.     Tempeh and miso

Tempeh is very similar to tofu: to make it, soybeans or grains are pickled and fermented by lactic acid bacteria. Tempeh has a meat-like texture and is tasteless and odourless.

In addition to probiotic bacteria, tempeh contains a lot of easily digestible protein as well as a high content of the minerals magnesium, potassium, and phosphorus.

Miso is a Japanese spice paste made from soybeans and grains such as rice or barley. During the long maturing period (often over a year), lactic acid bacteria ensure that the paste ferments and acquires its typical flavour.

Traditionally produced miso not only contains many probiotic lactic acid bacteria, but also a lot of proteins and dietary fibres.

Did you know that tempeh and miso are made without animal ingredients and are therefore particularly suitable for vegans? You can read more about veganism and the benefits of a vegan diet in our Health Portal.

8.     Kombucha

Kombucha is fermented tea that is very popular in Asian medicine. A mixture of special bacterial strains, yeast fungi and the kombucha fungus is added to sugared black or herbal tea. During fermentation, alcohol, acetic acid, lactic acid and gluconic acid are produced to create a tasty drink with carbonic acid. Kombucha tastes sour and contains between 0.7 and 1.3 per cent alcohol.^[22]

Kombucha is said to have numerous positive health effects. Among other things, the drink is said to help with gout, rheumatism, impure skin and also as protection against cancer and cardiovascular problems. However, these effects have not yet been confirmed in scientific studies.^[23]

Kombucha often contains large amounts of caffeine and sugar in addition to alcohol. Industrially produced kombucha, which you can buy in the supermarket or health food store, has been pasteurised and no longer contains probiotic germs.

Did you know that you can also make kombucha yourself (with the right hygiene standards)? Kombucha that is contaminated with foreign germs, especially mould, can cause problems for sensitive people, especially people with an immune deficiency.^[22] 

Are probiotic drinks actually good for you?

In recent years, many probiotic drinks have been advertised as particularly healthy. Probiotic drinks and yogurts with added probiotics can definitely be useful. However, you should consider a few things when buying them:

• The probiotic content decreases continuously after the drink/yogurt is bottled. The fresher the probiotic, the better.
• The best-before date does not indicate when the food is off. After expiry, however, the product no longer contains the minimum number of bacteria that makes it probiotic.
• Only 10 to 40 per cent of the lactic acid bacteria actually survive their passage through the stomach because of stomach acid.
• Beware of high sugar levels. Sugar serves as an energy source especially for bad bacteria.

What do probiotics do?

Experts link unhealthy intestinal flora – imbalanced gut bacteria – with a wide variety of diseases. Scientists are therefore conducting important research to identify more precisely what the health benefits are in probiotics and whether probiotic bacteria can help with diseases.

The benefits of probiotics have already been observed in people with the following diseases:^{[5, 6, 7]}

• Lactose intolerance
• Infectious diarrhoea
• Neurodermatitis
• Irritable bowel syndrome
• Ulcerative colitis

However, experts have not yet been able to make any clear recommendations regarding the benefits of probiotics. In other words, it is still uncertain how exactly and in what dosage probiotic bacteria can help with diseases or health issues. The composition of good intestinal bacteria is different for each person, as intestinal bacteria tests show, and cannot be so easily replicated by probiotics.

The environment in your gut probably also determines which bacteria can survive at all. This explains why the results are sometimes very different: sometimes, probiotic bacteria have a positive health effect and sometimes they don’t.^[8] 

Did you know that even the manufacturers of probiotic foods have not yet been able to clearly prove that the bacterial cultures used have a positive effect on health. Some advertising pertaining to these benefits may therefore not be used. The words ‘probiotic’ and ‘probiotics’ should also not appear on the packaging!^[9]

How do I promote good gut bacteria?

Diet has a very big influence on our intestinal health. Probiotic foods can have a great effect, but you should more first and foremost maintain a healthy diet in general.

Most studies show that a plant-based diet provides the best conditions for your good intestinal bacteria. The four most important recommendations are:^{[2, 5]}

• Enjoy colourful vegetables, fruits, herbs and spices. The natural colours promote protective types of bacteria in the gut.
• Eat vegetables, fruit or whole-grain products in every meal. This way, you feed your gut flora at the same time, as these foods provide fibre – what your gut bacteria feed on.
• Eat sour milk products such as yogurt, kefir, ayran, lassi or soured milk every day. Regularly include unpasteurised cheese, pickles, sauerkraut, Asian kimchi and tempeh in your diet. They provide healthy lactic acid bacteria that enrich the diversity of bacteria in your gut.
• Drink enough, preferably mineral water or unsweetened teas.

What are probiotics – at a glance

What are probiotic foods?

Probiotic foods contain sufficient microorganisms and promote positive health benefits in our gut.

These microorganisms include, for example, lactic acid bacteria such as lactobacilli and bifidobacteria, but also certain yeast fungi.

What probiotic foods are there?

Foods that are fermented during their production contain particularly high levels of probiotic bacteria.

These natural probiotics include, for example, sour milk products such as yogurt and kefir, hard cheeses such as cheddar and Parmesan, gherkins, sauerkraut, apple cider vinegar, Asian kimchi, miso, tempeh, and kombucha.

How do I promote healthy gut flora?

Make sure you eat a healthy, plant-based diet with plenty of fruits, vegetables, and whole grains.

Include probiotic foods in your diet regularly, and drink enough water and unsweetened teas.

Sources

^[1]       Bundesministerium für Bildung und Forschung, „Wir sind besiedelt: Darmbakterien beeinflussen unsere Gesundheit“, Ernährungsforschung – Was uns gesund hält. https://www.gesundheitsforschung-bmbf.de/de/wir-sind-besiedelt-darmbakterien-beeinflussen-unsere-gesundheit-8036.php, accessed on March 23, 2021.

^[2]       M. Groeneveld, „Gesund mit guten Darmbakterien - IN FORM“, Bundesanstalt für Landwirtschaft und Ernährung (BLE). https://www.in-form.de/wissen/gesund-mit-guten-darmbakterien/, accessed March 23, 2021. 

^[3]       Bundesinstitut für gesundheitlichen Verbraucherschutz und Veterinärmedizin (BgVV), „Abschlussbericht der Arbeitsgruppe ‚Probiotische Mikroorganismenkulturen in Lebensmitteln‘ am BgVV“, S. 8, Okt. 1999.

^[4]       Stiftung Warentest, „Milchsäure: Bakterien machen den Unterschied“, Erdbeer-Magerjogurt: Liebloser Aroma-Mix, Juli 01, 2005. https://www.test.de/Erdbeer-Magerjogurt-Liebloser-Aroma-Mix-1269080-1269164/, accessed on March 25, 2021.

^[5]       S. Röchter, A. Clausen, und J. Sausmikat, „Probiotika – Orientierung in einem unübersichtlichen Markt“, Ernährungs Umschau, Nr. 10/2020, pp. 69–76.

^[6]       Österreichische Gesellschaft für Ernährung (ÖGE), „Mikrobielle Kulturen und ihre Anwendungen in Lebensmitteln“. https://www.oege.at/index.php/bildung-information/ernaehrung-von-a-z/1777-probiotika-und-praebiotika, accessed on March 25, 2021.

^[7]       C. R. Kok und R. Hutkins, „Yogurt and other fermented foods as sources of health-promoting bacteria“, Nutrition Reviews, Bd. 76, Nr. Supplement_1, S. 4–15, Dez. 2018, doi: 10.1093/nutrit/nuy056.

^[8]       A. Gerlach, „Das Für und Wider – Pro- und Antibiotika“, Deutsche Apotheker Zeitung - DAZ.online, Feb. 25, 2019. https://www.deutsche-apotheker-zeitung.de/news/artikel/2019/01/01/das-fuer-und-wider-pro-und-antibiotika, accessed on March 25, 2021.

^[9]       Verbraucherzentrale, „Lebensmittel mit speziellen Bakterienkulturen (früher: ‚Probiotika‘)“, Verbraucherzentrale.de, Dez. 22, 2020. https://www.verbraucherzentrale.de/wissen/lebensmittel/kennzeichnung-und-inhaltsstoffe/lebensmittel-mit-speziellen-bakterienkulturen-frueher-probiotika-13937, accessed on March 25, 2021.

^[10]     Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen (IQWiG), 'Können Probiotika bei Durchfall helfen?' gesundheitsinformation.de, December 4, 2019, available at https://www.gesundheitsinformation.de/koennen-probiotika-bei-durchfall-helfen.html, accessed on March 30, 2021.

^[11]     Deutsche Gesellschaft für Ernährung e.V. (DGE), 'Milch und Milchprodukte,' DGE-Ernährungskreis, 2019, available at https://www.dge-ernaehrungskreis.de/lebensmittelgruppen/milch-und-milchprodukte/, accessed on March 30, 2021.

^[12]     J.-Y. Dong, J.-Y. et al. 'Effect of probiotic fermented milk on blood pressure: a meta-analysis of randomised controlled trials,' British Journal of Nutrition, vol. 110(7), pp. 1188–1194, October 2013, doi: 10.1017/S0007114513001712.

^[13]     Farag, M. A., Jomaa, S. A., Abd El-Wahed, A., El-Seedi, H. R. 'The Many Faces of Kefir Fermented Dairy Products: Quality Characteristics, Flavour Chemistry, Nutritional Value, Health Benefits, and Safety,' Nutrients, vol. 12(2), January 2020, doi: 10.3390/nu12020346.

^[14]     Deutsche Gesellschaft für Ernährung e. V., 'Essen und Trinken bei Lactoseintoleranz,' Novemeber 20, 2011, available at https://www.dge.de/presse/pm/essen-und-trinken-bei-lactoseintoleranz/, accessed on March 30, 2021.

^[15]     Ortakci, F., Broadbent, J. R., McManus, W. R., McMahon, D. J. 'Survival of microencapsulated probiotic Lactobacillus paracasei LBC-1e during manufacture of Mozzarella cheese and simulated gastric digestion,' J Dairy Sci, vol. 95(11), pp. 6274–6281, November 2012, doi: 10.3168/jds.2012-5476.

^[16]     CGyot, C. 'Quark und Joghurt: Was sind die Unterschiede?' October 06, 2020, available at https://www.molkerei-weihenstephan.de/news/milch-blog/quark-und-joghurt-was-sind-die-unterschiede, accessed on March 30, 2021.

^[17]     denn’s Biomarkt GmbH, 'Rödel Sauerkrautfabrik: Herstellung von Sauerkraut,' denn’s Biomarkt, April 17, 2020, available at https://www.denns-biomarkt.de/wissenswertes/bio-wissen/hersteller/roedel-sauerkrautfabrik/, accessed on March 30, 2021.

^[18]     Patra, J. K., Das, G., Paramithiotis, S. Shin, H.-S. 'Kimchi and Other Widely Consumed Traditional Fermented Foods of Korea: A Review,' Front Microbiol, vol. 7, September 2016, doi: 10.3389/fmicb.2016.01493.

^[19]     Ashaolu, T. J., Reale, A. 'A Holistic Review on Euro-Asian Lactic Acid Bacteria Fermented Cereals and Vegetables,' Microorganisms, vol. 8(8), August 2020, doi: 10.3390/microorganisms8081176.

^[20]     Miller, K. C. et al., 'Reflex Inhibition of Electrically Induced Muscle Cramps in Hypohydrated Humans,' Medicine & Science in Sports & Exercise, vol. 42(5), pp. 953–961, May 2010, doi: 10.1249/MSS.0b013e3181c0647e.

^[21]     Launholt, T. L., Kristiansen, C. B., Hjorth, P. 'Safety and side effects of apple vinegar intake and its effect on metabolic parameters and body weight: a systematic review,' Eur J Nutr, vol. 59(6), pp. 2273–2289, September 2020, doi: 10.1007/s00394-020-02214-3.

^[22]     'Kombucha,' Verbraucherzentrale.de, February 10, 2020, available at https://www.verbraucherzentrale.de/wissen/lebensmittel/kennzeichnung-und-inhaltsstoffe/kombucha-13938, accessed on April 6, 2021.

^[23]     Kapp, J. M., Sumner, W. 'Kombucha: a systematic review of the empirical evidence of human health benefit,' Annals of Epidemiology, vol. 30, pp. 66–70, February 2019, doi: 10.1016/j.annepidem.2018.11.001.