- Probiotics are live microorganisms that, when administered in adequate amounts, promote the health of their host.
- In the gut microbiota, they help regulate pH levels, support the integrity of the intestinal lining, and influence immune function.
- One of the greatest benefits of probiotics from dietary supplements is the precise knowledge of the specific cultures administered and their quantities.
Although there is currently no recommended daily intake for probiotic cultures, experts agree that regular consumption of probiotics through diet has a positive effect on the human body.
In addition to dietary supplements, probiotics can also be found in common foods. We have prepared a selection of the richest natural sources of probiotics, which can often be comparable in content to those found in supplements.
Probiotic microorganisms have been shown to have an effect on the human body
Although the concept of intestinal microflora was first introduced by French‑Russian scientist Ilya Ilyich Metchnikoff, the term "probiotic" did not appear until almost 60 years later, in 1965, and was initially used in a slightly different context. Since then, the definition has evolved several times, until 2001, when a widely accepted definition was proposed, describing probiotics as:
"...live microorganisms that, when administered in adequate amounts, confer health benefits to the host."
Much of the current knowledge about probiotics comes from the large‑scale scientific initiative known as the Human Microbiome Project (HMP), which was conducted in two phases from 2007 to 2016. Today, it is evident that the relationship between the human body and the gut microbiota is reciprocal. SSymbiotic microorganisms adjust (lower) the pH of the gut, helping to reduce the prevalence of pathogenic bacteria such as Salmonella or E. Coli.
The most commonly cited benefits include supporting the integrity of the intestinal mucosa, processing undigested food debris, and supporting immune function through the production of antimicrobial peptides or increased IgA production.
In dietary supplements and conventional foods, counted in millions
You can buy probiotics as dietary supplements in pharmacies or health food stores. The most common strains are Lactobacillus and Bifidobacterium, though specific yeasts (e.g., Saccharomyces boulardii) can also be used in some cases.
However, it is quite common to find probiotics in foods that are not highly processed. Even foods such as fruits, vegetables and whole grains are sources of probiotic cultures. However, fermented foods are among the richest sources, including fermented dairy products, fermented vegetables and fermented soy products.
Probiotic intake is typically calculated in CFUs (colonies per unit ). Rich sources of probiotics, such as dietary supplements and fermented dairy products, contain at least hundreds of millions of CFUs. For example, a dose of 100 million CFUs in a single capsule can be labelled as 1x10^8 CFUs.
However, there is currently no such thing as a recommended daily dose of probiotics. A recent study showed that, depending on the type of diet, people typically ingest an average of several million to a billion CFUs per day. For diarrhoea associated with antibiotic use, a daily intake of at least 5 billion CFU per day.
The 8 best natural sources of probiotic cultures
1. Kefir
Kefir is a traditional fermented dairy beverage made from kefir grains, which originate from the Caucasus and Tibet. The fermentation process gives it a slightly fizzy quality.
Kefir contains a mix of probiotic cultures, primarily lactic acid bacteria and yeasts that live in symbiosis. The minimum amount of microorganisms is set at 1x10^7 CFU in 1g of product.
2. Acidophilic milk
Acidophilic milk is characterised by the presence of the probiotic culture Lactobacillus acidophilus, with a minimum concentration of 1x10^6 CFU/g. Often, other cultures, such as Streptococcus thermophilus, are also included.
Acidophilus milk has a sharp taste, which is often softened by mixing it with creamed starter. It typically has a slightly higher fat content, about 3‑4 grams per 100 ml of product.
3. Yoghurt
Traditionally, yoghurt is made using a mixture of two probiotic cultures, Lactobacillus bulgaricus and Streptococcus thermophilus. These strains work synergistically to form the desired yoghurt texture and reduce the lactose content by approximately 20‑30 %.
In addition, some yoghurt manufacturers incorporate probiotic cultures of Lactobacillus acidophilus and Bifidobacterium, which are among the most studied for their health benefits. The microorganism content is set at 1x10^7 CFU per gram of product.
4. Kimchi
Kimchi is a collective term for various fermented vegetables, a tradition with over a thousand years of history in Korea. It remains widely consumed, with Korean adults eating an average of 130‑150g of kimchi per day.
Kimchi is primarily fermented by lactic acid bacteria but also undergoes processing by aerobic bacteria and yeasts. Additionally, it is a good source of prebiotic fibre and certain vitamins, including vitamin B12.
5. Sauerkraut
Sauerkraut is a traditional fermented food that dates back to ancient Greece. It was also popularised by James Cook in the late 18th century as a 'cure' for scurvy due to its vitamin C content.
Sauerkraut is a rich source of probiotic cultures, with the dominant lactic acid bacterium being Leuconostoc mesenteroides. The use of salt in the pickling process is important because, without it, the growth of other microorganisms would be favoured.
6. Pickled cucumbers
According to some estimates, cucumbers have been pickled for about 5000 years. Like other fermented vegetables, their sour taste comes from the presence of probiotic microorganisms that produce organic acids.
Pickles, like sauerkraut, are fermented in a slightly salty brine, which influences the composition of the microbial cultures. After about 15 days of fermentation, the amount of microorganisms present can reach up to 1x10^8 cfu in 1g of food.
7. Miso soup
Miso soup is one of the most classic dishes in Japanese cuisine, commonly eaten as part of breakfast. It is reported that there are now more than 1,500 producers of miso soup throughout Japan.
Miso soup is made from soybeans, rice, salt and starter culture. In addition to probiotic cultures, miso soup is rich in protein and contains a variety of antioxidants.
8. Actimel
Actimel is a commercial dairy product particularly rich in probiotic cultures. It contains 20 billion probiotic cultures of Lactobacillus casei per packet, which is many times more than the usual probiotic content of fermented milk products.
Due to its high probiotic culture content, Actimel can be used during and after antibiotic treatment to support the restoration of gut microbiota.
When does it make sense to take probiotics in the form of dietary supplements?
In certain situations, taking probiotics in the form of dietary supplements can be beneficial, as these supplements offer advantages over conventional foods.
- You know exactly which probiotics to take and in what quantity. Supplements often combine several different strains, along with prebiotics, to enhance the survival of the microorganisms.
- The amount of CFU is often much higher than in conventional foods.
Examples of situations where probiotics may be beneficial:
- During and after a course of antibiotics: More than 5 billion CFUs per day is recommended to mitigate the negative effects of antibiotics on the digestive tract.
- When travelling to exotic countries: A combination ofSaccharomyces boulardii yeast with Lactobacillus acidophilus and Bifidobacterium bifidum is often effective.
You can choose from products designed for preventive and long‑term support of the optimal composition of the gut microbiome, such as Vilgain Probiotics, products with even higher numbers of bacterial strains and CFUs like Vilgain Probiotic Compex or products with a special yeast strain that can be used during antibiotic treatment, such as Vilgain Saccharomyces Boulardii.
Bottom line
Probiotics are live microorganisms that, when given in adequate amounts, provide health benefits to the host. They can be obtained from dietary supplements or common foods, with fermented dairy products and vegetables being among the richest sources. A diet rich in fermented dairy products can be up to 100 times richer in probiotic cultures than a diet without them.
Consider including probiotics in the form of dietary supplements when taking antibiotics or travelling to exotic countries. The benefits of these supplements include precise knowledge of the microorganisms present and their quantities.
