The Benefits and Dangers of Fermented Foods

Tagged in: Digestive Health Immune Health

by Dr. Bryan Do, D.O. Last Updated: June 09, 2020

While fermentation has gained renewed modern interest, its roots go back to prehistory, providing an easy means of preserving foods and lengthening their shelf life. However, the fermentation process comes with its own benefits as well. Learn more about the potential benefits and dangers of fermented foods below.

What Are Fermented Foods?

Fermentation is a metabolic process involving microorganisms, like yeasts, molds, and bacteria. Microorganisms survive by feeding on sugars, starches, and other carbohydrates. They turn these carbs into necessary fuel and energy. Through this breakdown, fermentation results in the formation of various organic molecules as a byproduct. This includes alcohol and certain acids, particularly lactic acid.¹

Fermentation generally occurs in an anaerobic environment (an environment free of oxygen). Oxygen can actually inhibit the fermentation process. This is known as the Pasteur effect. However, certain fermented foods that use yeasts, like wine and beer, require a small amount of oxygen.²

Proper fermentation acts as a natural preservative that prevents food from spoiling as quickly, while imbuing food with a distinctly tart flavor and a variety of potential benefits, particularly involving probiotics.

Health Benefits of Fermented Foods

While fermentation was initially used as a means of making food last longer, modern research has shown that fermented foods may actually provide a wide range of health benefits.

Gut Health

One of the biggest benefits to fermented foods for gut health is the creation of beneficial bacteria known as probiotics. Your gut is naturally populated with a complex community of bacteria. Maintaining balance in this gut microbiome has been found to support nearly every aspect of your physical health. An imbalance in gut bacteria, referred to as dysbiosis, is characterized by an overgrowth of “bad” bacteria that can contribute to a whole host of digestive issues. Dysbiosis is also associated with infectious diseases and increased inflammation.⁴

Studies show that replenishing your gut bacteria with fermented foods and probiotics may help to improve digestive health. In a meta-analysis, supplementation with probiotic-rich foods improved the symptoms of gastrointestinal diseases.5 In another study, subjects who took fermented milk containing Bifidobacterium animalis had a beneficial effect on discomfort, bloating, and constipation associated with irritable bowel syndrome.⁶ This suggests that fermented foods may be beneficial for those who experience gastrointestinal problems.

Natural Immunities

Along with its effects on digestive health, the gut microbiome has also been found to influence your immune system. Studies show that probiotics may help to regulate the functions of immune cells and intestinal epithelial cells. These studies suggest that probiotics may play an important therapeutic role in certain issues related to immune response, including allergies, eczema, and viral infections.⁷

A meta-analysis also suggests that probiotics may help to prevent acute upper respiratory tract infections. The meta-analysis found that probiotics decreased the number of participants who experienced episodes of acute upper respiratory tract infection and reduced antibiotic usage, particularly in younger participants.⁸ Other studies actually suggest that probiotics may support faster recovery when you do get sick. One meta-analysis found that subjects taking probiotics were sick for a fewer number of days, had shorter illness episodes, and were absent from school or work fewer days.⁹

Furthermore, many fermented foods tend to be high in fiber, zinc, vitamin C, and other micronutrients that can support your immune system and contribute to better health overall.

Improved Digestion

The process of fermentation often results in enzymes that can help the human digestive system break down foods and components. For example, lactose is the sugar found in milk and other dairy products. Those who are lactose intolerant lack lactase, the enzyme responsible for breaking down lactose, and thus have trouble properly digesting milk products.

However, studies have found that consuming fermented dairy products, like kefir and yogurt, may improve lactose digestion and reduce the symptoms of lactose intolerance.¹⁰ Furthermore, Lactobacillus probiotics are able to break down lactose and create lactic acid which is the reason why some fermented dairy beverages, such as kefir, are lactose-free.¹¹

Fermented foods are also often more nutritious than their unfermented counterparts. The fermentation process has been found to break down phytates, lectins, and other antinutrients commonly found in seeds, grains, and legumes. These antinutrients can inhibit nutrient absorption and reduce bioavailability.¹²

Fermented Foods List

Given the right ingredients and environmental conditions, nearly any food can be fermented. However, the most common examples of fermented foods that you can buy or make yourself include:
- Kefir
- Yogurt
- Kimchi
- Sauerkraut
- Kombucha
- Tempeh
- Miso
- Natto
- Some (but not all) pickles
- Beer
- Wine

Types Of Fermented Foods

While there are thousands of fermented foods, you can generally break them down into three distinct types of fermentation.

Lactic Acid Fermentation

Lactic acid fermentation is one of the most common types of fermentation. Human muscle cells undergo lactic acid fermentation during strenuous physical activity. Essentially, the muscles use up more energy in the form of ATP before they can be resupplied with oxygen, leading to the buildup of lactic acid in the muscles, which contributes to general muscle soreness and aches.¹

The same process occurs in food as certain strains of bacteria or yeast convert sugars and starches into lactic acid. Strains of Lactobacillus bacteria are most commonly responsible for this process. Lactic acid fermentation is involved in making kimchi, sauerkraut, yogurt, pickles, and sourdough breads.¹

Ethanol Fermentation

Ethanol is a type of simple alcohol. Glucose in carbohydrates is metabolized in the process of glycolysis, creating pyruvate as a byproduct. Adding yeasts breaks down the pyruvate, converting it into alcohol and carbon dioxide molecules. This method of fermentation is involved with beer, wine, whiskey, and other alcoholic beverages.¹

Acetic Acid Fermentation

Acetic acid fermentation is a two-step fermentation process that yields vinegar. First, a carbohydrate is converted into alcohol via ethanol fermentation. Strains of bacteria known as Acetobacter are then added to begin the second fermentation process. These bacteria are readily found in nature, and unlike other forms of fermentation, acetobacters require oxygen to function.³ Acetic acid fermentation results in all forms of vinegar, including apple cider vinegar, wine vinegar, and kombucha.

How To Ferment Food

There are thousands of different fermented foods in the world, and it thankfully doesn’t take any complex equipment to ferment your own foods at home. Some basic tips to keep in mind if you want to begin fermenting your own foods:

- Maintaining an oxygen-free environment is the key to good fermentation. Exposing fermented foods to oxygen inhibits the process while allowing for the growth of unwanted yeasts and mold. Make sure you use airtight jars fitted with airlocks to prevent oxygen exposure.

- Similar to oxygen, sunlight can also destroy most lactic acid bacteria. Make sure your ferments are properly covered or stored in an area away from sunlight.

- Use organic, high-quality ingredients. Fermented fruits and vegetables rely on the bacteria and yeasts naturally found on the peels and rinds. Pesticides and herbicides often kill off those microorganisms and inhibit the fermentation process, on top of being just plain unhealthy for you.

- Vegetable fermentation tends to thrive at temperatures between 68 and 72 degrees Fahrenheit, while milk fermentation can thrive at temperatures up to 90 degrees Fahrenheit.

- Make sure that the equipment that you do use is properly cleaned and sterilized. You do not want to introduce outside microorganisms to your ferment.

- With the right temperature, the proper airlock, and time, you can generally achieve a successful fermentation, so be patient.¹³

Side Effects Of Fermented Foods

Fermented foods are considered safe for consumption by generally anyone. However, some people may experience mild side effects from the high probiotic content. This can manifest in the form of gas, bloating, and diarrhea, though these symptoms should subside as the gut gets used to the probiotics.¹⁴

Some fermented foods also tend to be high in biogenic amines. Amines are compounds that form naturally in fermented foods that contain protein and most commonly include histamine, tyramine, and tryptamine. While these are generally harmless, some people who are sensitive may experience headaches from increased amines.¹⁴

It’s also important to understand that not all fermented foods are created equal. Some fermented foods contain excess sodium or sugar, and while beer is a fermented food, it generally does not have high nutritional value.

Fermented foods can be an incredible addition to any diet, and they are easy to create in the comfort of your home. If you are looking to improve your gut health with probiotics consider taking a supplement, like DrFormulas® Nexabiotic®, either alongside or in lieu of fermented foods to maximize your probiotic intake.

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About the Author:

Dr. Bryan Do, D.O.

Dr. Bryan Do, D.O. is an osteopathic physician whose research interests include gastroenterology, immunology, and dermatology. He is particularly interested in the role of probiotics in the gut-brain-skin axis and has written many articles on the topic. He graduated from University of California, Los Angeles (UCLA) before graduating from Marian University College of Osteopathic Medicine in Indianapolis, Indiana and becoming a Doctor of Osteopathic Medicine. Osteopathic physicians are taught to take a holistic approach to medicine and to consider mind, body, and spirit when treating a patient. Osteopathic physicians receive training in Osteopathic Manipulative Medicine (OMM) in addition to the standard rigorous medical school curriculum. Both physicians with a Doctor of Osteopathic Medicine (D.O.) degree as well as a Doctor of Medicine (M.D.) can practice medicine.

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