The Power of Foods That Are Fermented

From kimchi to kefir: Check out 5 health benefits of fermented foods

A kimchi-topped burger. Fish drizzled with tangy tzatziki sauce. A salad drenched in miso dressing. Fermented options are popping up on restaurant menus and grocery store shelves — and for good reason.

There’s growing interest in foods that are fermented, thanks to their bold flavors and many health benefits. This age-old preservation process boosts shelf life and nutritional value, while giving you a healthy dose of probiotics — beneficial bacteria that support a healthy gut.

“People are looking for natural ways to improve their gut health, and fermented foods are a great place to start,” says Michele Bell, RDN, a registered dietitian nutritionist at Geisinger. “They introduce beneficial live microorganisms into your gut that can promote better nutrient absorption, reduced inflammation and stronger immune health.”

And you don’t have to dine out to enjoy them — and improve your overall health.

What are fermented foods?

Fermentation has been around for centuries. It’s a natural process where beneficial microorganisms — such as bacteria, yeast or fungi — feed on natural sugars and starches in food, converting them into end products like lactic acid, acetic acid and alcohol. This process not only preserves food, but also creates bold new flavors and textures, and populates it with live, helpful bacteria known as probiotics.

Sometimes these microbes are naturally present in the food, or they may be added to kickstart the fermentation process.

Foods that are fermented include:

Yogurt and kefir (cultured dairy)
Sauerkraut and kimchi (fermented cabbage)
Miso and tempeh (fermented soy)
Kombucha (fermented tea)
Sourdough bread

“Most people can enjoy foods that are fermented safely,” says Ms. Bell. “But if you’re pregnant or immunocompromised, talk to your doctor before making major dietary changes. The live bacteria can increase the risk of infection.”

Fermented vs. pickled: What’s the difference?

Pickling is also a way to preserve food, but it can be different from fermentation. Pickling usually relies on vinegar, salt brine or both to create that tangy flavor. Some pickled foods — like sauerkraut and dill pickles — are fermented because they rely on salt and natural bacteria to develop.

But many foods labeled “pickled” are simply soaked in vinegar. These quick-pickled products aren’t fermented and don’t contain the same beneficial bacteria.

“Fermentation depends on microbes transforming the food, so pickling doesn’t add health benefits if it’s not fermented,” says Ms. Bell. “All fermented foods are not pickled, and not all pickled foods are fermented.”

Health benefits of fermented foods

Fermented foods not only taste great and add to shelf life, but they offer many health benefits that go beyond healthy digestion:

Introduce probiotics for a healthy gut

Fermented foods contain live and active cultures that add good bacteria called probiotics to your gut.

So when you regularly eat fermented foods, it increases the diversity of your gut microbiome. This means you have lots of different types of beneficial bacteria living in your gut. And that diversity is a big part of overall health. The more good bacteria you have, the more they crowd out bad bacteria.

“A balanced microbiome leads to healthy digestion,” says Ms. Bell. “It helps break down food efficiently and can lead to regular bowel habits, less bloating and improved tolerance to certain foods.”

Improve nutrient absorption

Fermentation doesn’t just add good bacteria — it can also help break down nutrients and make digestion easier. And when food is easier to digest, your body can absorb more of the nutrients from the foods you eat.

During the fermentation process, certain compounds in complex carbs (i.e. whole grains and beans) that can interfere with nutrient absorption are broken down. That can make it easier for your body to absorb vital minerals like iron, zinc, magnesium and calcium.

In dairy products, fermentation breaks down lactose and can make yogurt and kefir easier to digest for some people with lactose intolerance.

Add vitamins and minerals to your diet

Fermentation also boosts nutrition in your food. The good bacteria involved in fermentation produce a variety of important nutrients, including B vitamins, vitamin K, calcium, magnesium and potassium.

“When you eat fermented vegetables, for example, you’re getting the added benefit of vitamin B12, which you wouldn’t otherwise get from simply eating raw vegetables,” says Ms. Bell.

Boost immune support and reduce inflammation

Your gut does a lot more than just digest food — it plays a huge role in your immune support, too. In fact, a big portion of your immune cells live in your gut.

When your gut microbiome is balanced and diverse, it helps strengthen your gut lining (your body’s protective barrier to prevent leakage into the bloodstream) and supports a healthy immune response.

In addition to immune support, eating fermented foods helps to reduce chronic inflammation — which is associated with conditions like irritable bowel syndrome, heart disease, Type 2 diabetes and certain cancers.

Support weight management

Yes, fermentation can play a role in weight management.

A healthy gut microbiome stimulates production of the body’s GLP-1 hormone, which helps regulate blood sugar and signals fullness. Fermented veggies, whole grains and yogurt can help you feel satisfied longer, so you may eat less.

Shopping for fermented foods for gut health

Fermented foods can come in a wide range of guises, but they all have one thing in common: They contain microbes.

When grocery shopping, choose refrigerated products that say “contain live and active cultures” or “naturally fermented.” Most authentic fermented foods are refrigerated to preserve live microbes, so the rows of jarred pickles and sauerkraut in center aisles don’t count.

Look for fermented products with simple ingredients and pay attention to sodium and added sugar.

“Sodium levels can be high in certain fermented foods like sauerkraut and kimchi, so choose lower salt varieties and balance portions with other whole foods,” says Ms. Bell. “And watch out for flavored yogurts, which can include added sugar. Try unsweetened or low-sugar varieties and add your own fruit.”

Tips to easily add foods that are fermented to your diet

If fermented foods aren’t a part of your regular diet, start small. Adding too much too quickly can lead to gas, bloating and stomach discomfort.

“Your gut needs time to adjust to the increase in fiber and beneficial microbes,” says Ms. Bell. Aim for 1 serving a day and build from there. And introduce 1 new fermented food at a time. That way if something doesn’t agree with you, it’s easier to pinpoint the cause.

She suggests a few easy ways to incorporate foods that are fermented into your daily diet:

Make a Greek yogurt parfait with granola and berries for breakfast
Add a spoonful of sauerkraut to your grain bowl or turkey sandwich
Swap white bread for sourdough
Top tacos with fermented veggies for extra crunch and tang
Stir kimchi into fried rice
Blend kefir into smoothies or your overnight oats for a creamy base
Whisk miso into salad dressings, marinades or soups

“There’s no need to overhaul your diet,” says Ms. Bell. “Small swaps and additions can make a big difference in bringing bold flavor and the many health benefits of fermented foods to your plate.”