By Barbara Bonner

Boosting Immunity with Lacto-Fermented Vegetables

Along with the current CDC recommendations* for the seasonal flu and for COVID-19, research has shown that efforts such as stress reduction, plenty of sleep, moderate regular exercise, a diverse diet full of brightly colored vegetables and fruit in all of the colors of the rainbow each day can boost your immune system. But did you know including a couple of forkfuls of lacto-fermented vegetables such as raw sauerkraut, kimchi and pickled vegetables or other probiotic-containing foods such as red miso, dairy kefir and water kefir that contain “good bacteria” not only support the health of the gut but also influence immune system functioning and regulation?

Historically, fermented foods have played an important role in the diets of most every society throughout the world. Beyond the culinary choices and preservation advantages of fermented foods is the natural phenomenon of fermentation performed by the cells within our bodies that helps to keep us healthy. With fermentation experiencing a renewed interest these days, it is good to understand some of the basic science regarding fermentation, and lacto-fermentation in particular.

The Science Behind Bacteria and Gut Health

Bacteria are responsible for lacto-fermentation. The “lacto” portion of the term refers to a specific species of bacteria, namely Lactobacillus. Various strains of these bacteria are present on the surface of all plants, especially those growing close to the ground (known as soil-based bacteria), and are also common to the gastrointestinal tracts, mouths, and vaginas of humans and other animal species. Many of us may be familiar with Lactobacillus acidophilus, commonly included in the process of making yogurt, but there are so many others.

Lactobacillus bacteria have the ability to convert sugars into lactic acid through a naturally occurring fermentation process. The Lactobacillus strain is so named because it can readily use lactose—the sugar found in milk—and convert it quickly and easily into lactic acid. However, lacto-fermentation does NOT need to involve dairy products. 

Lactic acid is a natural preservative that inhibits the growth of harmful bacteria. This phenomenon allowed people to preserve foods for extended periods of time before the advent of refrigeration or canning. Lactic acid also promotes the growth of healthy bacteria in the intestinal tract. That is why lacto-fermented foods are considered probiotic foods. Fun fact: Probiotic means “for life.”

There are many benefits to having abundant amounts of lactobacilli residing in our intestinal tracts as fermenting not only preserves food but also enhances the nutrient content. During the fermenting process the bacteria produce B vitamins and enzymes that are beneficial for digestion and makes the minerals found in fermented foods more readily available to the body.

What is Fermentation?

Culturing or fermenting a food involves the chemical process of breaking a complicated substance down into simpler parts, usually with the help of bacteria, yeasts, or fungi. Fermented food is considered a live food and the culturing process continues during storage to enhance the food’s nutrient content. All cultured vegetables have a natural tart or vinegary flavor as the sugars and carbohydrates have been broken down and used up in the process. The lactic acid also contributes to the tart taste of fermented foods. Raw fermented foods are so powerful you don’t need to eat large quantities to see benefits (think of them as a condiment rather than a food group) so don’t fret if you’re not a fan of tart flavors.

The Fermentation process can vary from a few hours to two months or more. The temperature of the room affects how fast or slow fermentation occurs, but more importantly, the length of time is dependent more on the flavor you prefer than anything else. Since the (sour) flavor level of lacto-fermented vegetables increases with time you will want to sample often until you are experienced enough to know what works for your tastes. Keep in mind that you don’t want to introduce a lot of oxygen to the fermentation process as this increases the chance of spoilage. And remember “under the brine and all will be fine.” After tasting, always re-submerge the vegetables under the brine. This mnemonic reminds us that when the vegetables are submerged under the brine, the bacteria that are present quickly use up all of the available oxygen, the liquid becomes anaerobic, and the bacteria that need oxygen are quickly replaced with anaerobic microorganisms which will decrease the chance for mold contamination. For this reason, lacto-fermentation is generally done in a container topped with an airlock or other method that prevents air from contaminating the culture.

What Can I Ferment?

Almost any vegetable can be fermented. Fermenting local, farm-fresh produce is a great way to provide good nutrition year-round. You can ferment just one vegetable or a mix of many different kinds. Beets with carrots, ginger, garlic, leeks, onions, seaweed, and jalapeños makes for a tasty mix. Kimchi recipes include cabbage, red chili peppers, garlic, ginger, and onion. Pickles can be spiced with dill and garlic; sauerkrauts can include juniper berries, caraway seeds, and more! If you have a reliable recipe to follow, you can make minor adjustments and personalize it to fit your unique tastes.

Many people are intimidated by lacto-fermentation. It’s important to know that you are not going to make your family sick by giving them home-fermented foods. Unless it smells unmistakably putrid (in which case common sense and your gut will tell you to throw it away), fermented foods are some of the safest foods you can eat. They are easy for a beginner to prepare and it doesn’t take long to gain enough confidence to venture beyond basic sauerkraut to an endless variety of vegetable and/or fruit combinations. Once you are brave enough to prepare and sample that first jar of sauerkraut or dilly beans, you are over the biggest hurdle. 

Fermenting vegetables at home is a rewarding process. With just a little patience, expert instruction, and minimal supplies, it is possible to easily learn the ancient art of lacto-fermentation. Ready to dig in? It’s your lucky day… we have lots of classes coming up so you can be on your way to becoming a fermentation expert:


* This information is only intended to identify modalities that may boost your immune system. It is not meant to recommend any treatments, nor have any of these modalities been proven effective against coronavirus (COVID-19) or the seasonal flu. Always consult your physician or healthcare provider prior to using any of these modalities. For up-to-date information on COVID-19 and seasonal flu, please consult the Centers for Disease Control and Prevention at