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What Makes Fermented Foods So Good For You (Plus, 4 You Should Try)

Julie M. Goolsby, M.A.
Author: Expert reviewer:
Updated on September 17, 2019
Julie M. Goolsby, M.A.
Written by
Julie M. Goolsby, M.A.

Julie M. Goolsby, M.A., received her Master's degree in women's studies from Georgia State University.

Megan Fahey, M.S., R.D., CDN
Expert review by
Megan Fahey, M.S., R.D., CDN
Registered Dietitian
Megan Fahey, M.S., R.D., CDN is a Registered Dietitian, Functional Medicine Nutritionist and Registered Yoga Teacher. She holds her Masters of Science in Nutrition and Dietetics from Bastyr University, where she was trained to artfully blend eastern and western healing modalities.
Image by Gillian Vann / Stocksy
Last updated on September 17, 2019

Fermented foods have been around for thousands of years, and now, what's old is new again. Historically, fermentation was used to preserve food, but recently, it has been gaining popularity for major health benefits like improving digestion and mood. Beer, wine, yeast breads, salami, and yogurt are all examples of fermented foods. Other fermented foods you may or may not have heard of include kefir, kombucha, and miso.  

But what exactly is fermentation, and why are fermented foods so great? Keep reading to learn more about the benefits of fermented foods.

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What is fermentation?

Fermentation is the process of breaking down organic substances—such as vegetables, fruits, grains, fish, meat, and dairy products—by introducing yeast or beneficial bacteria.

There are three basic types of fermentation:

  • Lactic acid fermentation1: Relying on yeasts and bacteria to convert starches and sugars into lactic acid, this type of fermentation is used to make fermented foods such as sauerkraut, kombucha, kimchi, and bread. Fermented foods produced using lactic acid fermentation contain live microorganisms.
  • Ethyl alcohol fermentation2: This type of fermentation uses yeast to break down starches and sugars to make wine and beer. It does not produce live microorganisms (probiotics).
  • Acetic acid fermentation3: With this type of fermentation, vinegar, also known as acetic acid, is used to make fermented foods.
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Depending on the method used, the process of fermentation encourages the growth and proliferation of bacteria, called probiotics. Probiotics are the "good" bacteria that help your body digest food and promote a healthy gut microbiome. Many of the health benefits attributed to fermented foods are due in large part to their probiotic content.

To be sure you are buying fermented foods that contain probiotics, look for the phrase "naturally fermented" on the package label.

Health benefits of fermented foods.

Research supports that probiotic-rich fermented foods offer a range of health benefits4 by enhancing the gut microbiome. Eating a diet rich in fiber, plants, and fermented foods helps ensure that your gut microbiota—the microorganisms living within your digestive tract—are diverse and thriving. We now understand that the phrase, “you are what you eat” is more accurately, “you are what you digest and absorb.” Optimizing the balance of bacteria in the gut through regular consumption of fermented foods is vital to get the nutrients from your food into your cells. It comes as no surprise then that fermented foods have been shown to contain powerful antioxidant, anti-hypertensive, and anti-diabetic properties. Here is more information outlining the science-backed benefits of eating fermented foods:

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They improve digestion.

 We now know that having a healthy microbiome improves the integrity of the gastrointestinal tract5. This includes protecting the intestinal mucous membrane from leaking, helping the body to absorb nutrients better, and helping to protect against digestive diseases such as inflammatory bowel diseases (IBD), colon cancer, as well as other health conditions like metabolic syndrome and atherosclerosis (hardening of blood vessels). 

Several studies6 have also shown that eating fermented foods such as yogurt, kefir, and sauerkraut may help protect gut health. Fermented foods such as yogurt, kefir, and sauerkraut can help to not only improve gastrointestinal health, but also may be useful in treating intestinal disorders such as infectious diarrhea. Another study showed that consumption of probiotic foods may also help protect against the 7H. pylori7 virus7, a stomach infection that can lead to certain types of gastric cancers.

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They boost your immune system.

Probiotics stimulate the immune system8, alerting it to harmful bacteria and triggering a response.  

A variety of both animal and human studies have shown that the importance of probiotics in helping to promote a healthy immune system. The impact includes alleviation of gastrointestinal and inflammatory symptoms in autoimmune disorders.9

They enhance mental health.

You may be surprised to learn that your gut and your brain have a close relationship, known as the gut-brain axis (GBA)10. Researchers have learned that what goes on in your gut can make a serious impact on your brain and vice versa. 

For example, dysbiosis, which occurs when gut microbiota are out of balance, has been associated with everything from irritable bowel syndrome (IBS) to central nervous system disorders.

And to make matters more complicated, , drugs intended to treat psychological or neurological conditions, such as antidepressants and pain relievers, have been shown to affect digestive health11

Having a healthy, diverse microbiota plays a key role in helping your body maintain this important gut-brain relationship. This is especially important for mood regulation, considering up to 90% of our serotonin, an important brain neurotransmitter sometimes called the "happiness hormone," is produced in the gut.

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Fermentation vs. pickling: What's the difference?

How does fermentation differ from pickling? Both fermentation and pickling are used to preserve foods. The difference between the two processes is that pickled foods are preserved using a salt solution (known as a brine) or an acid such as vinegar instead of yeast or bacteria. 

An easy example of a pickled food is "quick" pickles, which are shelf-stable pickles. Quick pickles are cucumbers that have been soaked in hot vinegar.

But guess what? Some foods are both pickled and fermented! For example, traditional pickles are made by first soaking the cucumbers in brine and then allowing them to ferment. Another example of this dual process is sauerkraut, which is made by pickling cabbage in a brine and then letting the mixture ferment.

But are fermented foods safe? 

Adding fermented foods to your diet can be an easy and flavorful way to boost your health. 

In general, fermented foods are safe to eat. However, it's important to follow proper preparation techniques if fermenting at home to avoid contamination and mold. 

If you have food sensitivities such as lactose intolerance or yeast allergies, you will want to avoid some fermented foods. Also, if you're new to eating fermented foods or foods high in probiotics, it's a good idea to start slowly. These foods can cause gas and bloating, so it is helpful to allow your digestive system to adjust. 

For those who are recovering from certain digestive disorders such as candida or SIBO, you may want to go easy on introducing fermented foods. It's always important to check with your health care practitioner before making any major dietary changes, especially if you have a medical condition or are taking medications.

If you are pregnant or nursing, it is important to note that some fermented foods are contraindicated. For example, although studies are limited, it may be unsafe to drink kombucha during pregnancy or breastfeeding. Again, speak with your health care practitioner if you are a new or expecting mom before introducing new foods into your diet. 

Note that if consumed in large amounts, the caffeine in kombucha can aggravate some digestive conditions such as diarrhea and IBS.

How to add fermented foods to your diet.

Fermented foods are commonly found in cuisines throughout the world. And while these foods originated due to concerns about food preservation, they also have deep cultural roots.

Here's are some fermented foods to get you started:

  • Kimchi
  • Kefir
  • Yogurt
  • Kombucha

When buying fermented foods, it's very important to read the label and check the expiration date. The label should say "live active culture." Look for bacteria such as Lactobacillus, Bifidobacterium, or Bifidobacterium lactis HN019. It's also a good idea to pick up these items at the end of your shopping and keep them cool on the way home to ensure the cultures remain active.