Fermentation is an ancient technique of preserving food.

The process is still used today to produce foods like wine, cheese, sauerkraut, yogurt, and kombucha.

Fermented foods are rich in beneficial probiotics and have been associated with a range of health benefits — from better digestion to stronger immunity (, ).

This article takes a look at food fermentation, including its benefits and safety.

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Fermentation is a natural process through which microorganisms like yeast and bacteria convert carbs — such as starch and sugar — into alcohol or acids.

The alcohol or acids act as a natural preservative and give fermented foods a distinct zest and tartness.

Fermentation also promotes the growth of beneficial bacteria, known as probiotics.

Probiotics have been shown to improve immune function as well as digestive and heart health (, , ).

Therefore, adding fermented foods to your diet may benefit your overall well-being.

Summary Fermentation is a process that involves the breakdown of carbs by bacteria and yeast. It results in a distinctive tart flavor and is used to make foods like yogurt, cheese, and sauerkraut.

A number of health benefits are associated with fermentation. In fact, fermented foods are often more nutritious than their unfermented form.

Here are the key health benefits of fermented foods.

Improves Digestive Health

The probiotics produced during fermentation can help restore the balance of friendly bacteria in your gut and may alleviate some digestive problems ().

Evidence suggests that probiotics can reduce uncomfortable symptoms of irritable bowel syndrome (IBS), a common digestive disorder (, , ).

One 6-week study in 274 adults with IBS found that consuming 4.4 ounces (125 grams) of yogurt-like fermented milk daily improved IBS symptoms, including bloating and stool frequency ().

What’s more, fermented foods may also lessen the severity of diarrhea, bloating, gas, and constipation (, , , ).

For these reasons, adding fermented foods to your diet may be useful if you regularly experience gut issues.

Boosts Your Immune System

The bacteria that live in your gut have a significant impact on your immune system.

Due to their high probiotic content, fermented foods can give your immune system a boost and reduce your risk of infections like the common cold (, , ).

Consuming probiotic-rich foods may also help you recover faster when you’re sick (, , ).

Additionally, many fermented foods are rich in vitamin C, iron, and zinc — all of which are proven to contribute to a stronger immune system (, , ).

Makes Food Easier to Digest

Fermentation helps break down nutrients in food, making them easier to digest than their unfermented counterparts.

For example, lactose — the natural sugar in milk — is broken down during fermentation into simpler sugars — glucose and galactose ().

As a result, those with lactose intolerance are generally fine eating fermented dairy like kefir and yogurt ().

Plus, fermentation helps break down and destroy antinutrients — such as phytates and lectins — which are compounds found in seeds, nuts, grains, and legumes that interfere with the nutrient absorption ().

Therefore, consuming fermented beans or legumes like tempeh increases the absorption of beneficial nutrients, making them more nutritious than unfermented alternatives (23, 24).

Other Potential Benefits

Studies have shown that fermented foods may also promote:

  • Mental health: A few studies have linked the probiotic strains Lactobacillus helveticus and Bifidobacterium longum to a reduction in symptoms of anxiety and depression. Both probiotics are found in fermented foods (, ).
  • Weight loss: While more research is needed, some studies have found links between certain probiotic strains — including Lactobacillus rhamnosus and Lactobacillus gasseri — and weight loss and decreased belly fat (, ).
  • Heart health: Fermented foods have been associated with a lower risk of heart disease. Probiotics may also modestly reduce blood pressure and help lower total and “bad” LDL cholesterol (, , , ).
Summary Fermented foods have been associated with several positive health effects, including improved digestive health, stronger immunity, and increased availability of beneficial nutrients.

Fermented foods are considered safe for most people. However, some individuals may experience side effects.

Due to the high probiotic content of fermented foods, the most common side effect is an initial and temporary increase in gas and bloating ().

These symptoms may be worse after consuming fiber-rich fermented foods, such as kimchi and sauerkraut.

It's also important to note that not all fermented foods are created equal.

Some products may contain high levels of added sugar, salt, and fat — so it’s important to read nutrition labels to make sure you’re making a healthy choice.

If fermenting at home, make sure you follow recipes closely for safety purposes. Incorrect temperatures, fermentation times, or unsterile equipment can cause the food to spoil, making it unsafe to eat.

Summary Fermented foods may cause some initial side effects, such as gas and bloating. If fermenting at home, always follow recipes to avoid spoilage and read nutrition labels when consuming store-bought products.

There are many different types of fermented foods consumed around the world, including:

  • Kefir
  • Sauerkraut
  • Tempeh
  • Natto
  • Cheese
  • Kombucha
  • Miso
  • Kimchi
  • Salami
  • Yogurt
  • Sourdough bread
  • Beer
  • Wine
  • Olives
Summary Fermented foods are popular worldwide. Common ones include tempeh, kombucha, kefir, cheese, salami, yogurt, and sourdough bread.

Fermentation is the breakdown of carbs like starch and sugar by bacteria and yeast and an ancient technique of preserving food.

Common fermented foods include kimchi, sauerkraut, kefir, tempeh, kombucha, and yogurt. These foods may reduce heart disease risk and aid digestion, immunity, and weight loss.

Not to mention, fermented foods add tang and zest to your meals and are an excellent addition to a healthy diet.