When I first tried homemade miso (versus the off-the-shelf kind), I had a gut-wrenching reaction similar to mild food poisoning or some sort of miso-induced food allergy.
Of course, there was a chance that I had messed up the ferment and was experiencing food poisoning… However, no one else had any issues with the miso. And it looked, smelled, and tasted good. It was definitely not food poisoning…
…My body was just reacting to a new type of fermented food.
When can fermented foods cause problems?
Fermented foods are brimming with probiotic cultures that are great for improving your gut health and general wellness. They are more likely to survive digestion than a probiotic supplement. And they’re delicious!
However, there are a few circumstances where fermented foods can cause unpleasant side effects.
Here are a few reasons why fermented foods might not be good for you:
- Certain fermented foods are not recommended for pregnant women, children under the age of 1 year, or anyone who is immunocompromised. Like raw eggs, unpasteurized cheese, and honey, certain fermented foods be unsafe.
- If you are allergic to something in fermented foods, then it’s going to cause problems. Fermenting does not remove gluten, soy, or dairy allergens.
- Fermented foods tend to be high in histamine and MSG. So if you’re sensitive to either of these, avoid eating large servings of fermented foods.
- Side effects can also occur when introducing new fermented foods to your diet.
Common side effects of fermented foods
Wondering why new fermented foods may cause side effects?
It’s because they are bringing a whole new set of probiotic friends to the party in your digestive system.
When the probiotic cultures don’t get along a fight ensues. A few of the unsavory types end up getting kicked out as the brawny newcomers assert themselves. Then slowly, over time, your digestive system will settle down as everyone finds a new equilibrium.
Some of the common side effects of fermented foods include:
- Gas and bloating
- Nausea and diarrhea
- Dizziness and racing heart
A strong reaction isn’t always a bad thing, especially if you were eating fermented foods to improve your gut health. However, if the reaction feels like an allergy or exasperates allergy symptoms, then I recommend avoiding that particular type of ferment in the future.
How to prevent side effects
A gut-wrenching reaction to a new ferment may actually be a good thing! It means that you are slowly bringing the microbiome in your gut back into a healthy balance. This is particularly true if you were eating fermented foods to recover from antibiotics.
Regardless, self-punishment is not the way to introduce new probiotic cultures. Never overdo it thinking that you’ll cure yourself quicker. There is no point in suffering if you don’t have to.
Here’s how to prevent possible side effects of fermented foods:
- Ferments that are made with an airborne culture should not cause a large reaction, as they are already in your home. This includes sourdough and ginger bug.
- Only try a small amount (1 Tbsp) of any fermented cultures that are very new to you. Personally, I reacted to miso and water kefir. However, other unique fermented cultures include heritage yogurt strains, milk kefir, kombucha, jun, and raw tempeh.
- Continue eating a tablespoon of the new probiotic food every day for a week so that your body can adjust to the new culture of bacteria and yeasts.
- After a week, feel free to try a small serving. If it doesn’t cause any digestive symptoms then you’re free to eat as much of that fermented food as you want.
Have you had a problem with a particular fermented food? Share in the Facebook group Fermenting For Everyone or in the comments below.
Do you have a nice forseradish recipe made with real horseradish and cream?
I have a recipe for fermented horseradish, which is like a store bought jar of horseradish: https://www.fermentingforfoodies.com/archives/2213
I would like to know if the fermented fresh from garden Horseradish will be losing its spiciness after fermenting. I still didn’t figure out how to preserve Horseradish and keep it just as sharp as it is when fresh. Any advice will be helpfull Thank you
Fermenting does take some of the heat out of horseradish. But it will still be spicy (just like commercial horseradish). Maybe freezing grated horseradish will keep the heat? I’m not sure. Good luck!
I found that when I first started making my own milk kefir, I was having reactions to it only in the morning. It was taking small amount, about 1-2 tablespoons while I was straining my grains to start another batch. When I added my kefir to my smoothies, I could tolerate larger amounts without side effects. The solution for me was to not take kefir on an empty stomach, and to take it with other foods. I have been making my own kefir for a month now and no longer have side effects. I love it with nothing added to it, it is so tasty and addictive.
I wonder if with time it will help me become tolerant to cheese? I have not been able to eat cheese and other dairy for quite a while, even with Lactaid tablets or tried lactose free cheese and couldn’t tolerate it. I really miss cheese – being able to drink kefir and make crean cheese and butter from it has been a real blessing.
Great!
Danielle; if its milk protein (your reaction to cheese will probaly be worse than to a little milk, and my strongest symptoms were stomache ache and feeling tired), then I have experience with this:) It turned out the problem was leaky gut & candida. So getting lots of probioticss from clutured food is great, because it can get your candida in check. I also cut sugar & fast carbs to stop feeding the candida, and cut wheat to let my intestines heal. You could also add glutamine to help the healing After 3-4 months I could start having small amounts of chese again:)
Please may i know how to make gluten free sourdough using water kefir . Thanking you in anticipation.
I have hashimoto thyroiditis and need to go gluten free.
Hi Pauline, Answered on your other comment. Good luck!
Thankyou for sharing your wealth of knowledge and experience. God bless you and may your health prosper .
I started with a big jar of fermented onions. Then miso-fermented onions, then cauliflower and jalepenos and carrots. All turned out great!
Then rejuvelac. Lime jalepeno rejuvelac, honey ginger rejuvi…on and on.
I had no idea about fermented foods (I’m an off-gridder living way out in the woods) but jumped right in.
Anyway, it made me quit smoking and it reduced my alcohol consumption by at least half. I really have no desire.
It’s got my diet in incredible shape: one good meal a day (incredible, as I’m a big eater, and love my three-a-day…although I don’t think three is necessary).
Anyway, all going great in my fermenting world EXCEPT massive, uncontrollable diarreah. Yuk!
I love, love, love all this food and don’t want to even reduce my consumption…but…
Hum… it sounds like you changed a lot of things in your life. It might take a while for your digestive system to catch up. If the fermentation is causing problems then it will take about 2 weeks to adjust. But if other things are causing changes (like the amount of fiber… or increased stress) then it will take longer to settle down. Running on stress and adrenalin can also cause loose stools. Take care!
Ok so I have a question about how fermented foods are affecting my gut. About a month ago I had a jar of sauerkraut that I bought from a locally made produce, Bend Root Cellars. I was using it as a condiment on some of my foods and had zero negative reactions. When I ran out, I went and bought another jar, This jar was soft and not as crunchy as the last one, and I had some bloating/stomach pain/ diarrhea during the three days I ate a small amount of it. I figured maybe something was amiss in the fermentation process, so I figured I would dump that jar. I went and bought a jar of the same brand’s kimchi. It tastes amazing, smells right, and is nice and crunchy. I put two heaping spoonfuls on my breakfast yesterday, and less than 20 minutes later had three rounds of loose stools (basically brown water in the toilet, sorry TMI). This morning, I thought I would try a smaller amount. I put 2 teaspoons (just like one bite, really) on my potatoes and eggs with breakfast, same thing. Within 10-20 minutes, an urgent need to defecate and all that came out was brown water. I’m confused, because I had no problem with the first jar of sauerkraut! What gives? Any opinions, suggestions, insights would be helpful. Trying to figure out if this means I shouldn’t keep trying to eat the kimchi, or if I should just keep doing a tiny amount and hope that my body adjusts. Thanks!
Hum… I have a few thoughts (though I’m by no means able to offer a medical opinion). It definitely seems like you are having a reaction to the fermented vegetables. While that wasn’t an issue the first time around, it seems like it’s happening now. Our gut health can change dramatically in a matter of just a few weeks. Changing your diet, going on a course of antibiotics will definitely affect it. If neither of those apply to you, then it could be related to stress. Pretty much everyone I talk to these days is burnt out from the “covid rollercoaster”. And that is certainly enough to cause a change in your gut health.
Normally, I would suggest to keep trying a little bite each day for a week. But at this point, whether you keep eating just a tiny amount every day (to slowly adjust) or take a break is up to you. We all need as much TLC as we can offer ourselves and those around us. So do what feels best. Be well, Emillie
I am used to eating fermented foods weekly since I was a young child.I can drink kombucha, kefir and eat any other fermented food but kimchi. I started with a store bought vegan,mild kimchi and loved the flavor.Unfortunately,soon after I literally lived in the bathroom with watery diarrhea and loud rumbling stomach (sorry for giving tmi).I decided to buy a traditional kimchi which was a bit spicy and made with fish sauce.Same thing happened. Because I loved the flavor so much,I decided to make it at home.I found a recipe which has fish sauce (I used redboat brand) and used korean pears instead of rice flour.Came out amazing.Everyone loves it,including my 11 year old son.Unfortunately,a more severe bathroom brake happened after first time eating it (just me and no one else in my family) and continued after each time eating it.
Like I said,we eat a lot of sauerkraut and fermented foods, and this is the only thing that gives me this type of reaction (well,gluten too as I have celiac).We also eat raw napa cabbage in salads, so I don’t think I have an allergy to it.
Not sure what is it.Any ideas?
Hum… that is a mystery. Maybe the red pepper powder? I would guess the fish sauce, but you said the vegan kimchi also was a problem. I imagine you’re used to garlic, ginger, onions, radishes, etc.? Clearly, something is not reacting well. Take care!
I am just suddenly experiencing pain i what is i the directiin of my Liver …alrhough it could be a transferred pain from my haites hernia it does alsi cause that kind of pain …otherwise i have no other issues …no bloating ir anything …I hope its not going to hamper me too much …i just love the flavoured Kombucha …today i did jave kefir also for a change …and some home pickled fermented cucumber , onion and tomato . I used to have Candida issues but i think its been much reduced by the ferments i ingest. and my allergies has been practically wiped away . ..
If the pain is very bad I recommend seeing a doctor. It could be something unrelated to fermented foods… even appendicitis. Otherwise, I’m glad that fermented foods have been so helpful for you! Please take care, Emillie
Hi Emillie
What a great page! Will certainly stick around a bit 🙂
And here’s my question: Turns out I‘m allergic to sulfur (E220 – 228). Do you know how to avoid it in a fermentation process, especially kombucha? Thanks a lot in advance 🙂
Johanna
Thanks! Wow, sulfur is a tough allergy. I’m not as familiar with it, since it’s not an issue anyone in my family has (and I am not a doctor/allergist/naturopath). However, I do know that sulfur can be produced by certain strains of yeast. Though sulfur-producing yeasts are not typically found in kombucha, local, wild yeasts may colonize kombucha creating sulfur.
Probably the best way to manage this is to try just a little bit of a ferment and test if it bothers you. Good luck!
Hi,
I’ve added sauerkraut to my diet since a week now. I’ve been feeling very very tired whole week, I was wondering if it could be related. I read just now you should start with just a tablespoon, I started off with about 4 or so. I will now stop eating it for a day or 2 and then start again slowly. Of course the tiredness can have a totally different cause. Anyways thanks for all the lovely tips!
I’ve never heard of a ferment causing tiredness. However, if not eating sauerkraut gave you more energy then it could be related. Thanks for sharing!
I’m glad I came across this! I’d been having some unpleasant reactions to tepache and was wondering if it was just the way I made it or if it was a sign that my body was healing from candida (a good thing). After reading this, though, I think I will cut back a bit or try drinking it with a full stomach. Thank you for this!
Glad this was a help! I’ve been making a LOT of tepache recently. Hopefully, you can build up some tolerance to it. It is so good!
Hello I am struggling with environmental allergies and many food intolerances. I introduced unpasteurized pickles/one per day in hopes for a better quality of life. I unfortunately became very sick. migraine/headaches weak tired. I stopped the pickle per day and realized that the brine itself was also problematic. It had sea salt and sea salt drains my energy. white bread and cold cuts are a no no for sure. I’m at a loss and struggling. I do take probiotic in the morning on an empty stomach, before breakfast. I would be grateful for some feedback.
Sorry to hear about your problems. I am not a doctor or a nutritionist, so I can’t really offer more than advice based on my experiences. However, if you are sensitive to histamines or yeast, then pickles might continue to cause a reaction. Yogurt is the best option for avoiding yeast. Dairy is also the best option for actually getting probiotics to survive digestion as calcium protects against stomach acid. If you can’t handle dairy, then you can always try non-dairy yogurts. I wrote a post about it here: https://www.fermentingforfoodies.com/probiotics-survive-digestion/
Take care!