Can You Eat Too Many Fermented Foods? What The Science Says

• Too Many Fermented Foods?|
• Who Should Avoid Fermented Foods|
• Increase Your Tolerance|

In today’s climate of confusing health information, there seems to be one thing everyone in healthcare can agree on: The beneficial bacteria in probiotic supplements and foods like yogurt are, in fact, really good for your digestive system. Probiotics—the microorganisms found in fermented foods—promise a wide array of scientifically backed health benefits.

Fermented foods have been around for millennia, playing a role in nearly every ancient and indigenous culture and traditional cuisines across the globe.

• Sauerkraut and many different types of pickled/fermented vegetables come from German and Eastern European heritages. 
• Kimchi (spicy fermented cabbage) is Korean. 
• Miso and natto (fermented soybean products) are Japanese. 
• Kefir and yogurt are from central and northern Europe. 
• Kombucha and kvass are Russian and Slavic bubbly drinks. 
• Tempeh (also made from soybeans) is Southeast Asian. 
• Indigenous Americans eat various fermented foods made from corn, fish, meat, and fruit—staples that likely once shifted based on location and availability.

Most of these foods contain not only living bacteria that support your gut microbes and microbial diversity but also antioxidants, amino acids, enzymes, and healthy carbs.

All this is to say that fermented foods touch the lives of nearly every culture on the planet, supporting the gut bacteria that facilitate overall health and wellness for those who partake. 

But can you have too much of a good thing? Can you eat too many fermented foods? And are there folks who should not eat fermented foods at all?

Let’s look at the specifics.

Can You Eat Too Many Fermented Foods?

Eating too much of anything can cause problems—it’s even possible to drink too much water. While fermented foods are likely no different, at the moment, we don’t have enough scientific research to establish guidelines or recommended limits. So, you’ll need to experiment with your intake to determine where your personal limits are with fermented foods.

Limited Preliminary Research

One interesting but not conclusive study found a positive association between high intake of fermented foods and depression and anxiety during stressful situations 1. In the study, 372 medical students reported eating an average of about 3.5 cups of fermented foods per week. Those who ate more than 3.5 cups a week of fermented foods experienced more feelings of depression and anxiety. 

Note: An association or correlation can’t help us determine cause and effect—did the fermented food yield the mental health symptoms, or did those who already had mental health symptoms eat more fermented foods? We need more research in this area, but it’s worth paying attention to your mental health as you consume fermented foods.

These findings are interesting and worth learning more about because they run counter to the research that shows probiotic dietary supplements  are supportive of mental health conditions like anxiety and depression. 

Contamination and Food Safety

As with everything you put in your mouth, it’s important to ensure that the fermented foods you’re eating are high-quality and not contaminated with harmful microbes. A pretty surefire way to experience negative side effects from eating fermented foods is by eating contaminated products 2. Because these foods are often sour or tart due to fermentation, it’s easy to forget that they still have expiration dates you should honor.

Who Should Not Eat Fermented Foods?

People with certain health conditions may want to consider limiting or eliminating fermented foods from their diet until the condition resolves. 

If you have histamine sensitivity or histamine intolerance, you might want to avoid fermented foods. Fermented foods are naturally high in histamine, and a small subset of people get allergy-like symptoms when they eat fermented foods 3.

If you have FODMAP sensitivity or conditions that cause it, like small intestinal bacterial overgrowth (SIBO), leaky gut, or irritable bowel syndrome (IBS), you might find that fermented foods upset your stomach. FODMAPs are specific types of carbohydrates that can be difficult for some people to digest. Common side effects include bloating, distension, excessive gas, constipation, and urgent bowel movements.

Interestingly, in some cases, the fermentation process makes the raw ingredients easier to digest. For example, soybeans are a high-FODMAP food, but tempeh, which is made from soybeans, is a low-FODMAP food. Certain grains and flours also start out high FODMAP but change to low when they become sourdough bread 4: 

FODMAP limits are dose-specific, meaning a small amount of certain foods can be fine for those with sensitivities. Monash University created an app to help you determine the ideal quantities of foods you need to limit.

How to Increase Tolerance of Fermented Foods

The live bacteria and beneficial microbes in fermented foods can offer tremendous benefits to your gut microbiome and, therefore, your digestive health and immune system. 

Many fermented foods also contain prebiotics, which are fibers that feed the good bacteria already living in your gut. While plenty of non-fermented foods contain prebiotics, those foods may also be high-FODMAP or more difficult to digest than their fermented counterparts. Foods like legumes, certain dairy products, and otherwise healthy veggies may cause digestive distress for particularly sensitive individuals.

So, increasing tolerance of fermented foods could be a good idea to support your health and well-being. Gut health is central to your overall health, including mental health, stress tolerance, and sleep quality.

Heal Your Gut First

If you struggle to digest fermented foods, the first step is likely to start healing the gut. Histamine sensitivity and FODMAP sensitivity may arise from a leaky gut or gut dysbiosis, and probiotics can help repair both.

In the clinic, we use triple therapy probiotics to help alleviate histamine intolerance symptoms, such as bloating, diarrhea, abdominal pain, constipation, brain fog, rash, and allergies.

In general, probiotics are a net antihistamine 5 6. You don’t need special “low-histamine” probiotics, even if you have or suspect histamine intolerance 5 6. A triple therapy approach is good for most people, but if you react to supplements, you can take one probiotic category at a time, building up to all three.

Our Clinical Protocol

At our clinic, we have clients who are sensitive to fermented foods stop eating them and replace them with a probiotic supplement. As their gut health and microbiota improve, they can slowly test their tolerance to fermented foods with small amounts.

Unless you’re making your own fermented foods using safe practices, look for labels on fermented products that say: 

• Organic
• Unpasteurized
• Contains “live active cultures” or is “naturally fermented” 

The process of introducing various foods that contain probiotics is slow and methodical, ensuring that if the client has a reaction, we can pinpoint which food is most likely to have caused it. The process of healing the gut can take time, but after a few months, you will begin noticing the signs that your probiotics are working and hopefully, your tolerance for fermented foods will improve.

Fermented Foods for a Healthy Gut

While scientific rigor and large-scale studies are the gold standard, clinical experience, anecdotal evidence, and a rich history of hundreds of cultures across the globe using particular healing foods are also compelling and important pieces to consider when evaluating which foods to eat and how much. Fermented foods are part of that rich human history, which is still alive today in many traditional cuisines.

While it may be possible to eat too much fermented food, researchers don’t actually know what too much is, so it’s up to you to listen to your body as you test it out. If you have sensitivities, it’s likely a good idea to start a gut-healing protocol, which can reduce your sensitivities and allow you to slowly incorporate fermented foods into your diet.

If you’d like help getting started on your journey to healing your gut, we would love to help. Reach out to our clinic to schedule a consultation. You may also be interested in a self-guided experience with my book, Healthy Gut, Healthy You.

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