Fermented Foods for Gut Health

The digestive system is a complex ecosystem, host to trillions of microorganisms including over 400 bacterial species. 

It’s vital to keep the ecosystem balanced with the proper diet. Many look to fermented foods as a component. 

Are fermented foods really the key to a healthy gut? How do they compare to probiotics?  This article reviews the benefits of fermented foods to discover if they are the key to long term gut health.

What are Fermented Foods?

Fermentation is a process in which carbohydrates are broken down to alcohol or organic acids by bacterial exposure.

Fermentation is a desired process as it improves the foods’ digestibility and offers a variety of health benefits. 

Beneficial bacteria found in fermented foods include species like Lactobacillus, Bacteroides, Bifidobacterial, and Enterococcus.

The earliest record of fermented foods was in the Fertile Crescent in 6000 B.C. Fermented foods have been reported in nearly every culture since then.

Summary: Fermented foods have been around for thousands of years.  They can provide many benefits to the human body due to the beneficial bacteria found within them.

Fermented Foods

There are a variety of fermented foods to consider including in the diet. 

Some of the foods you are already eating may be fermented.  Coffee, for instance, is fermented and the length and technique of the fermentation determines the final flavor of the coffee.  Tea, cheese, wine, and pickles are also all commonly consumed fermented foods in the American diet.

Here are some of the best fermented foods from around the world (1):

  • Yogurt- Greece/Turkey
    • A sweet or sour dairy product depending how it is made, produced by the bacterial fermentation of milk.
  • Kefir-Russia
    • A drink made from combining bacteria and yeast. Kefir has a similar texture to yogurt and its taste is largely dependent on the type of milk used, usually sour.
  • Sauerkraut-Germany
    • A crunchy, salty, and sour cabbage that has been fermented by lactic acid bacteria.
  • Kimchi- South Korea
    • Usually spicy, kimchi is salted and fermented cabbage and Korean radishes giving it a pickled vegetable taste.
  • Kombucha-Russia/China
    • Kombucha is fermented black or green tea that possesses a vinegary taste.
  • Miso-Japan
    • A savory and salty Japanese seasoning produced by fermenting soybeans with salt and koji.

Ways to Incorporate Fermented Foods

  • Adding chopped pickles to tuna or chicken salad
  • Add yogurt as a side to your breakfast
  • Add sauerkraut to almost any dinner
  • Make your own salad dressing using fermented mayonnaise or cultured buttermilk
  • Use sourdough bread to make sandwiches
  • Drink kombucha to replace soda or juice
  • Have miso soup as an appetizer

It is worth noting that food processing techniques makes a drastic difference on the probiotic content the food provides.  Bacteria cultures are sensitive to heat; therefore, pasteurization can kill many of the beneficial bacteria in your food.

This is why it is important to look at the quality of your food sources to make sure that you are still getting the benefits.  If a product is pasteurized, read the label to see if the manufacturers added “live and active” cultures following pasteurization.

Summary: Many common foods are fermented, however, there are many other ways to incorporate a variety of fermented foods   Bacteria cultures are very sensitive to heat so foods subject to pasteurization may not contain all of the beneficial bacteria you are looking for.

Health Benefits

There are many ways fermented foods can improve your health. 

Fermented foods can improve digestion by adding “good” bacteria to your gut. Improving the composition of gut bacteria can improve your body’s ability to digest and absorb nutrients from those foods (2).

Brain Health

Improving gut health has implications beyond the digestive system.  Research is now finding that gut bacteria also play a major role in the prevention of many neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. They also  have links to anxiety and depression. This is because bacteria in the gut can send signals to the brain from the digestive system through a system referred to as the gut-brain axis (3, 4). 

Immune Health

In addition to gut and brain health, fermented foods can boost the immune system since nearly 80% of the immune system is in the gut.  

Much of the bacteria in fermented foods helps detoxify the body by binding to and removing harmful toxins and heavy metals (5). 

Metabolic Health

While boosts in digestive health and immunity are crucial, fermented foods can also improve metabolism and blood lipids and reduce the risk of certain types of cancer (2).

As if that wasn’t enough, many fermented foods are also nutrient dense meaning they contain a wide variety of micro and phytonutrients, adding to their beneficial properties.  

Summary: Fermented foods can impact our overall health by improving brain, digestive, metabolic, and heart health.

Fermented Foods Compared to Probiotics

Since fermented foods contain probiotics, one may wonder how they compare to probiotic supplements. 

Fermented foods offer a wider variety of beneficial bacteria as well as an abundance of nutrients like B-vitamins and amino acids, important to overall health.

Comparatively, probiotic supplements may provide higher doses of specific types of beneficial bacteria. Additionally, there are certain probiotic formulations studied to help support medical conditions like antibiotic associated diarrhea, C.diff infection, ulcerative colitis, pouchitis, and IBS.

However, their role in other health conditions is still unclear. Also, they can be costly and not always provide the probiotic content stated on the label. This is due to quality degradation that often occurs upon exposure to heat, light, and changes in pH.

Check out this site to learn more about the research behind certain probiotic products: http://usprobioticguide.com/

Currently, there is no research comparing fermented foods to probiotic supplements. If you are seeking to improve your overall health then it is likely that fermented foods may be your best choice since they contain a wider variety of beneficial bacteria and nutrients. Also, there is no proven benefit of probiotic supplements for general health.

Summary: There are pros and cons to both fermented foods and probiotics.  Probiotics can provide you with heavy doses of specific bacteria, but fermented foods with provide you with a wider variety of bacterial strains and extra nutrients.

Safety of Fermented Foods

It’s possible for any food, including fermented foods, to contain harmful bacteria like Listeria and Salmonella. 

Therefore, it’s important to know the source of the food and the quality of its preparation.  Food processing leads to an increased risk of foodborne infection due to the use of contaminated raw material, lack of proper pasteurization, and poorly controlled natural fermentation (6).

Summary: It is important to know where fermented foods come from and that they have been handled properly by trusted sources to ensure your safety.


Incorporating fermented foods is one component to an overall healthy gut.

Having a healthy gut can improve not only digestive health, but also brain health, feeling of well-being, heart health, and even reduce the risk of cancer.

Everyone can benefit from incorporating more fermented foods into the diet.  Fermented foods are the perfect strategy for improving gut health due to their content of many beneficial bacteria and additional vital nutrients. 

by Chris Irvin M.S. Exercise and Nutrition Science