Probiotics, Medicine and Kimchi: How to Make Smart Choices in a World Full of "Healthy" Options

By Jekaterina Kazantseva, Head of Microbiome Research

Walk into any pharmacy or health food store these days, and you're met with shelves bursting with supplements, superfoods, powders, and capsules. The message is clear: to be healthy, you must buy your health, one capsule at a time. But for everyday people trying to make informed choices, this can be overwhelming. How do you know what actually works? And when it comes to probiotics, is all that marketing backed by science?

Let’s break it down. What are probiotics, really? Probiotics are defined as live microorganisms which, when taken in adequate amounts, confer a health benefit on the host. But here’s the catch: that definition only applies if three strict conditions are met: The microbes must be alive when consumed; they must be taken in a sufficient quantity; and their effect must be clinically proven for a specific purpose. If even one of those criteria isn’t met, it’s not a true probiotic - no matter what the label says. Unfortunately, many supplements on the market fall short.

From Lab to Capsule: A Rough Journey

Let’s start with the first challenge: keeping the microbes alive. Probiotic strains are grown in industrial bioreactors, then harvested, dried into powders, and packed into capsules. Each step of the process can damage or kill the bacteria. And unlike pharmaceutical drugs, probiotics are not always held to strict quality-control standards. So by the time they reach your gut, many may already be dead - and dead bacteria don’t help.

Even if they survive manufacturing, they still have to pass through your stomach acid, bile salts of the small intestine, and compete with trillions of existing gut microbes. It’s a microbial obstacle course. That’s why dosage matters. To have a chance at making a difference, probiotics must be taken in large enough numbers - typically billions of units or living microbes per dose. On the label, they are sometimes described as CFU (colony-forming unit), a scientific term showing how many of them are capable of living and reproducing. But even if they survive and arrive in large numbers, we’re still not done.

Targeted Help or Just Hype?

Now comes the real question: Why are you taking probiotics in the first place? After antibiotics course? For bloating? To prevent hay fever? Most of us grab a product based on packaging, price, or vague memories of something we read online. The more strains, the better - right? Not necessarily.

Firstly, we have to clarify what the term strain means. A strain is a version or type of a living thing, like bacteria, viruses, or plants. We can compare bacterial strains with dog breeds. Let’s say we’re talking about a bacterial species, like Bifidobacterium breve. That’s like talking about dogs in general. Just like dogs come in different breeds (Labrador, Poodle, Bulldog), bacteria come in different strains. For the probiotic Bifidobacterium breve strain, it will be coded as M-16V.  So, we are not talking about all Bifidobacterium breve in general,  but specifying a group with individual features. What really matters is whether the strain has been clinically tested for your specific health concern. Probiotic effects are strain-specific, just like different medications are used for different illnesses.

Now, some combination of complex Latin words and numbers will appear. Be patient and don’t be afraid of them, their names are really important, as only these (and several others) coded guys are verified microbes that can be proudly titled as probiotics.

Here are some evidence-based examples of the microbes carrying a high mission: Lactobacillus rhamnosus GG (LGG) and Saccharomyces boulardii (a beneficial yeast) have been shown to prevent antibiotic-associated diarrhoea and support microbial recovery; Bifidobacterium infantis 35624, Lactobacillus plantarum 299v, and Lactobacillus acidophilus NCFM have proven effects on digestive issues such as excessive gas, bloating, or constipation. Bifidobacterium breve M-16V and Lactobacillus casei Shirota can help reduce mild allergic reactions, food sensitivities and gut inflammation.

New trends in probiotic research are exploring new possibilities for their consumption. One of them – prescribing probiotics with potential benefits for treating mild anxiety and depression, improving sleep quality and managing stress. This new class is called psychobiotics, and its effect is especially strain-tailored. For example, it was shown that the combination of unique strains of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 reduces anxiety and depression scores comparable to antidepressants without any side effects of medication. 

So far, many clinically proven benefits of probiotic consumption have been identified - pretty exciting, right? And research in this field is ongoing, so we're likely to hear about even more advances in the near future.

The Estonian Case: What’s in Our Probiotic Capsules?

To better understand the quality of probiotics available in Estonia, researchers at TFTAK launched a small investigation with two high school students: Anna-Maria Shenkina (Tallinn Tõnismäe Riigigümnaasium) and Ingmar Hunt (Tallinn Reaalkool). Guided by scientists Anne Meikas and Aili Kallastu, they tested five Estonia-connected probiotic products and five commonly recommended by doctors.

Analysing product labels and using traditional and modern microbiological methods, including DNA sequencing, they evaluated whether these products truly matched the definition of a probiotic. The result? Half of the products failed. Some had no strain names listed. Others didn’t contain enough live bacteria. In several cases, the bacteria listed on the label weren’t even present and replaced by entirely different species. We cannot blame producers in this, as very often they buy microbial cultures in a powder form from manufacturers with uncontrolled technological processes and certificates.  While most of these supplements aren’t harmful, their health benefits are questionable. It’s not enough for a capsule to say “probiotic” - it has to deliver.

So... Should You Take Probiotics at All?

Yes - but choose wisely. Probiotics can be powerful tools for specific health goals, but only when the right strain is used in the right amount for the right purpose. The best way to choose a probiotic? Ask a professional: your doctor or pharmacist. Don't just go by pretty packaging or vague promises.

Now, you've known all these great options that probiotics can offer you, but you are not keen on supplement consumption. Alright, fair enough. And here’s a bonus tip for you: eat fermented foods!

Fermented Food: Nature’s Probiotic

Surprise! You don’t have to take a capsule to get beneficial bacteria.  Just eat sauerkraut, kimchi, yoghurt (classic or plant-based), kefir (milk or water), tempeh, miso, kombucha,  or just traditional pickles. These foods can contain millions to trillions of live lactic acid bacteria per gram - no fancy labelling required. Plus, fermented vegetables also provide fibre, antioxidants and vitamins that help feed your gut bacteria. You don’t even need to know every species inside. Wild fermentation creates microbial diversity, and diversity is key. And you’re not just getting bacteria. Fermented foods often contain beneficial postbiotics (biologically active molecules created by microbes) and prebiotic fibers, which work together to improve gut health. Minuses exist as well. The consumed bacteria are dark matter, as well as their good features and functions. The generalisation that something is just good indeed doesn’t always work. Especially, if we have a problem to resolve.

Back to the Lab – And the Future

At TFTAK, we’re taking it a step further. As part of a European research initiative, we’re working with partners in France, Italy, Ireland, and Germany to isolate bacteria from traditional fermented foods - like olives, cereals, saurkraut, and water kefir - and study their health benefits. The goal? To develop next-generation gut- and mood-friendly functional foods that blend scientific evidence with culinary tradition. Imagine a saurkraut that not only supports digestion but also improves your mood. Or a fermented grain bar tailored to reduce inflammation. This is no longer science fiction - it’s where food innovation is heading.

Food as Medicine, Food as Pleasure

So yes, food can be medicine. But it should also be a joy to eat. Whether you love crunchy sauerkraut, spicy kimchi, or smooth kefir, fermented foods offer both flavour and function. And if you choose supplements, make it an informed choice. Look for specific strain names with references to studies or trials, clear CFU counts (ideally 1 billion or more per dose), and check for storage instructions (many need refrigeration). And most importantly: ask questions. Your gut microbiome is as unique as your fingerprint. There’s no one-size-fits-all solution. But with the right guidance and curiosity, you can find what works for you, what your gut will really love. Because when it comes to probiotics, it’s not about following trends - it’s about finding targeted, tested, and trustworthy solutions for better health.

The article was published in Estonian in the magazine Kodutohter in November 2025.

Read the Estonian-language version here:

Kuidas teha teadlikke valikuid probiootikumide maailmas Jekaterina Kazantseva 2025.pdf

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