fermented foods

Fermented foods like yogurt, kefir, sauerkraut, kimchi, and kombucha are some of the most famous fermented foods in the USA. They’re famous for improving gut health, boosting digestion, reducing inflammation, and much more.

Fermentation is a natural process through which microorganisms like bacteria and yeast break down carbs and sugars. This process results in the production of beneficial compounds, including organic acids, polyphenols, probiotics, vitamins, and enzymes.

Nevertheless, there are certain individuals who should avoid or limit their intake of fermented foods due to potential risks. In this article, we will discuss the dangers of fermented foods and a list of people who should not eat fermented foods.

People Who Shouldn’t Eat Fermented Foods

dangers of fermented foods

Fermented foods are generally considered not only safe, but super healthy for most people. However, here are some individuals who should limit or avoid them:

People with Histamine Intolerance

Histamine is a compound that is naturally present in our bodies. It plays a role in various physiological functions, such as immune response and digestion

Histamine is also found in many foods, including fermented foods. When we consume histamine-containing foods, our bodies break down the excess histamine using an enzyme called diamine oxidase (DAO).

But some people may have a deficiency of DAO, which can lead to histamine intolerance. In these individuals, consuming histamine-rich foods (like fermented foods) can cause allergic reactions, such as headaches and stomach upset. Symptoms can range from mild to severe and can occur immediately or many hours after consumption. 

Histamine intolerance is more common in women than men. Moreover, it’s often misdiagnosed as an allergic reaction. All in all, people with histamine intolerance should limit or avoid fermented foods. 

download all our cookbooks today

People with Compromised Immune Systems

Fermented foods are made using various strains of bacteria and yeast. These microorganisms are responsible for the fermentation process. 

These microorganisms are generally considered safe, but some can cause infections in people with weakened or compromised immune systems. This includes individuals with HIV/AIDS, cancer patients undergoing chemotherapy, and organ transplant recipients. In these individuals, consuming fermented foods can lead to side effects such as fever, diarrhea, muscle aches, and headaches. 

Children and Pregnant Women

Pregnant women and very young children (less than one year old) should also avoid eating certain fermented foods—for instance, fermented meat, mold-based ferments, and raw cheese or eggs.  

We’re not saying pregnant women should avoid fermented foods altogether; but they should pay extra attention to the serving size and type of fermented food they’re adding to their diets.

Here are some fermented foods that are generally considered safe for pregnant women to eat: 

  • Miso  

  • Kimchi

  • Sauerkraut

  • Tempeh 

  • Yogurt

  • Kefir

However, moderation is the key here—avoid eating too much of these foods in one sitting. 

People with Digestive Disorders

Fermented foods are often recommended for people with digestive disorders like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). This is because of the potential of fermented foods to improve gut health and reduce inflammation. 

Fermented foods are high in probiotics, which are live bacteria and yeasts that are beneficial for our gut microbiome. However, some strains of probiotics can produce gas and bloating in people with sensitive digestive systems. 

Thus, people with digestive disorders should consult with a registered dietitian or healthcare before adding fermented foods to their diets. 

People on a Strict Sodium-Restricted Diet

A low-sodium diet is recommended for people with high blood pressure or other conditions that need them to limit their sodium intake. But, many fermented foods such as lacto-fermented pickles, sauerkraut, and miso can be high in sodium. 

Salt is necessary for preserving the food and giving it its unique flavor. Thus, people on a low-sodium diet should be mindful of their fermented food consumption, and moderate their intake of high-sodium fermented foods.

[product_render product-handle="continuous-kombucha-starter-kit"]

Dangers of Fermented Foods

Have you recently tried fermented foods and noticed some discomfort in your gut? You're not alone. For some individuals, the introduction of new probiotic cultures to their digestive systems can cause some temporary side effects. This is because the new cultures may not immediately mesh well with the existing ones, leading to a temporary disruption in the gut microbiome. 

But rest assured that these side effects are generally nothing to worry about. With time, your gut will adapt and find a new equilibrium. Let's take a closer look at some of the most common side effects of fermented foods:

Gas and Bloating 

As we said earlier, fermented foods contain probiotics, which can promote the growth of beneficial bacteria in the gut. However, some people may experience gas and bloating as a result of increased bacterial activity in the digestive system.


In some cases, consuming too many fermented foods can lead to diarrhea. This is particularly common in individuals with pre-existing digestive conditions.

Allergic Reactions 

allergic reaction as dangers of fermented foods

Some people may be allergic to certain fermented foods, particularly those made with grains or dairy. Allergic reactions may include hives, swelling, and difficulty breathing. Just pay attention to what goes inside your favorite fermented food and see if you’re allergic to it before consuming it. 

To avoid any sudden allergic reactions, try making your favorite fermented foods at home. You’ll only need a couple of fermentation supplies and ingredients of your choice. You can also check out our fermented vegetable kit, which has everything you need to make any fermented vegetables

Food Poisoning 

If the food you're fermenting isn’t properly prepared (e.g., not washing hands, supplies, ingredients, etc.) or stored, you risk having harmful bacteria in your food, which can lead to food poisoning. People with weakened immune systems, pregnant women, and children should especially watch out for this.

It's always a good idea to practice good food safety habits. For instance, washing your hands, cooking food properly, and avoiding cross-contamination.

A Note on Side Effects of Fermented Foods

All the above-mentioned side effects are generally temporary and mild, and not a cause for concern for most people. However, if you experience persistent or severe symptoms after consuming any fermented food, speak with a healthcare professional to rule out any underlying medical conditions or allergies. You should also make sure to consume fermented foods in moderation and practice proper food safety and storage techniques to reduce the risk of contamination.

Wrapping Up: Who Shouldn't Eat Fermented Foods?

Fermented foods are safe and super healthy for most people. However, people with histamine intolerance, compromised immune systems, and digestive disorders should first consult their healthcare provider before adding fermented foods to their diets. 

People with certain food allergies should try to make their own fermented foods at home with proper food safety. This will keep them safe from any sudden side effects of fermented foods. 

Similarly, pregnant women, infants, and elderly people should also be mindful of their consumption of fermented foods. Always eat fermented foods in moderation, and don’t overdo them.