How Much Fermented Foods Should You Eat?

Written by: Kari Raman, PharmD, RPh
Published October 24, 2023

A pharmacist reviews the science about how much fermented foods you should eat for a healthy microbiome. 

The vibrant world of fermented foods has been at the heart of many cultures for centuries. But with the rise of health and wellness trends, there is starting to be a lot of marketing hype around supposed health benefits of fermented food. 

As a pharmacist, I often consult about the health benefits of probiotics. With a recent study titled “Consumption of Fermented Foods Is Associated with Systematic Differences in the Gut Microbiome and Metabolome,” I’ve got the data I need to compare how fermented foods do for gut health vs. probiotic supplements. Of course, the pressing question I get in the pharmacy from people interested in their microbiome is, “how much fermented foods should I eat?” Let’s see what science says!

The Science I Used

The study, Consumption of Fermented Foods Is Associated with Systematic Differences in the Gut Microbiome and Metabolome, was published in the journal mSystems (a journal that focuses on research in metabolic systems). The study took a close look at how eating fermented foods might impact our gut health. Using data from the American Gut Project and some new research, they found differences in the gut bacteria of people who regularly eat fermented foods compared to those who don’t. (The American Gut Project is one of the largest citizen science projects focused on the microbiome, involving tens of thousands of participants.) In simpler terms, foods like yogurt, kimchi, or sauerkraut might have a role in influencing the mix of bacteria in our stomach and intestines, which can affect our overall health. It’s like how certain medications might change our body’s reactions; in this case, it’s food playing that role.

The Magic Behind Fermented Foods

Ok, it’s not really magic. But, when foods undergo fermentation, it’s not just about flavor enhancement and preservation. This process leads to the growth of beneficial bacteria (and sometimes yeast), which when consumed, might provide benefits similar to those offered by probiotics supplements.

Fermented Foods: A Haven for Your Microbiome?

According to the study, consuming fermented foods could influence our gut microbiome. But rather than altering the overall microbial diversity, they tend to cause subtle yet systematic compositional shifts. Much like how taking a specific probiotic supplement introduces certain strains of beneficial bacteria to the gut, fermented foods introduce a variety of good bacteria, potentially creating a diverse and balanced microbiome.

Probiotics and Fermented Foods: Two Sides of the Same Coin?

While probiotics are specific strains of bacteria (or yeast sometimes) known for their health benefits, fermented foods are rich in a variety of beneficial bacteria. In this respect, the advantages of consuming fermented foods might overlap with those of probiotics. Both aim to foster a healthy balance of gut flora, which in turn may benefit digestion, immunity, and overall well-being.

How Much Fermented Foods Should You Eat for Optimal Benefits?

Based on current medical recommendations, there’s no strict guideline on how much fermented foods you should eat. However, this study does shed some light on how incorporating a serving of fermented foods daily might be a good approach. Whether it’s a dollop of sauerkraut, a refreshing swig of kombucha, or a bowl of yogurt, these fermented delights might offer myriad health benefits. 

More on What the Study Says on How Many Fermented Foods You Should Eat?

Participants in the study were categorized based on their frequency of consuming fermented plants: “daily,” “regularly (3 to 5 times/week),” “occasionally (1 to 2 times/week),” “rarely (less than once/week),” or “never.” Interestingly, a little over 30% of participants consumed fermented foods, with most of them being occasional consumers. 

Some key observations? 

Those who ate fermented foods regularly showed distinct differences in their gut microbiome when compared to non-consumers. Moreover, the difference in gut microbial communities between those who consumed fermented foods daily or regularly and non-consumers was more pronounced than between occasional consumers and non-consumers. This suggests a possible dose-dependent relationship: the more frequently you consume fermented foods, the more distinct your gut microbiome might be. But remember, individual responses can vary, and it’s always good to consult with a healthcare provider regarding dietary choices.

My Summary on How Many Fermented Foods You Should Eat

It seems like there are some modest changes to the microbiome between people who sometimes eat fermented foods and people who don’t ever eat them. So my opinion would be to eat fermented foods regularly, but not obsessively. Several times a week seems to be enough to confer microbiome changes and possible gut health benefits.


One, if you are having health issues you should always talk to a doctor first.

Second, not all foods are equal.

Not All Fermented Foods Are Created Equal

It’s essential to note that not every fermented item you come across in the grocery aisle will have the probiotic potency you might expect. Some commercial fermented products, like certain pickles, might be simply brined in vinegar rather than traditionally fermented. Always check labels, and when in doubt, ask or research.

Like I talk about in my article “how much probiotics are in yogurt,” look for foods labeled “live and active cultures.” Dairy, at least, when it says that it has live and active cultures must have at least 100 million cultures per gram at the time of manufacture. 

Other foods that use fermentation, however, may not have any probiotic-like benefits. Of course, beer comes to mind! But also, baked goods like sourdough bread don’t contain living probiotics because they are killed during the baking process.

The “How Much Fermented Foods Should You Eat” Takeaway

Thanks to the research, it’s clear that fermented foods may hold a special place in promoting gut health. While they might not replace probiotics, they certainly complement them. 

If you’re keen on fostering a vibrant gut microbiome, perhaps the age-old tradition of fermentation is something to savor. Remember, it’s not just about “how much fermented foods you should eat” but also about the quality, variety, and regularity of consumption. As with any health journey, it’s about balance, mindfulness, and enjoying the process. Cheers to a happy gut!

Pharmacist Kari Raman

I’m Kari Raman PharmD, RPh, and I am a licensed, practicing pharmacist. I hold a Doctorate in Pharmacy from The University of the Pacific, and I’ve served patients in retail, compounding and hospital pharmacies.

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