Fermentation is one of the oldest forms of food preservation, predating crop-based agriculture. As early as 8000-3000 BC, foragers in Asia fermented vegetables because doing so increased shelf life (1). Fermenting foods allowed our ancestors to survive famine, making it a necessary part of dietary culture. All ancient traditions utilized fermentation, and depending on the food supply, different cultures have fermented vegetables, fruits, grains, dairy products, and even fish and sea mammals.
Fermented foods are a source of probiotics because they contain lactic acid bacteria (LAB). LAB is a gram positive, non-spore forming bacteria that ferments the carbohydrate in vegetables into lactic acid. LAB possess functional properties that contribute to positive health impacts in humans. Some of these functions include lowering cholesterol, improving immune function, preventing diarrhea, and generally improving the health of the gut, which in turn impacts all body systems (2). The health benefits of LAB have been documented since the early 1900s, when scientist Elie Metchnicoff theorized that lactic acid could extend the human lifespan based on his studies on the yogurt consumption of Bulgarian peasants. The yogurt, like fermented vegetables, is rich in probiotics. Probiotics, meaning ‘for life’ are bacteria with known health benefit for humans. The mechanisms of action of probiotics are still being studied, but some of their main functions from which we derive health benefits include their ability to compete with pathogenic bacteria in the gut, their ability to secrete antimicrobial substances, their role in toxin inactivation, and their function in modulating the immune system.
Fermenting vegetables is incredibly simple, and you likely have all you need to ferment in your kitchen right now. All you need is an airtight glass jar (and possibly some plastic wrap), purified water, salt, and your vegetables. If you choose to, adding certain spices and herbs can both enhance flavor and improve quality.
Vegetable fermentation utilizes an organic acid fermentation process. Salt is the key ingredient in this type of fermentation process. The salt in a vegetable fermentation promotes the growth of LAB and inhibits the growth of spoilage bacteria (2). Fruits and vegetables harbor a variety of microbes, including aerobic microbes that will spoil the produce if allowed to flourish. Brining, or submerging the vegetables in a salted medium results in the production by LAB of organic acids and antimicrobial compounds (1). Adding a few cloves of garlic inhibits the growth of spoilage bacteria. Adding mustard seed further inhibits the growth of pathogenic microbes. Mustard seeds contain allyl isothiocyanate, a volatile aromatic compound with antibacterial and antifungal properties. As such, it inhibits the growth of yeast and increases the production of LAB (3).
Fermentation also changes the organoleptic characteristics of foods, such as the flavor, aroma, and texture. But far more compelling is the impact of fermentation on the nutritional value of vegetables. Fermentation improves the digestibility of foods and improved the nutritional quality. Lactic acid in foods increases the utilization of Calcium and Phosphorus and the absorption of Iron and Vitamin D (3). And these benefits do not include the aforementioned benefits of probiotic bacteria. Long story short, you’re missing huge health benefits if you’re not including fermented vegetables in your diet!
Unfortunately, those of us raised on the standard American diet (the ‘SAD’ diet) are generally unfamiliar with fermented vegetables. When most of us think of pickles, we think of the pickled cucumber. Unsurprisingly, in the US, the ‘pickling’ process has changed since cucumbers were first pickled in the Middle East around 2000 BC. The American retail market for pickles is dominated by pasteurized products that are not fermented (1), thus without any of the benefits mentioned above. Nearly all of the pickles you can pick up at the grocery store are given their pickled taste and texture from the use of vinegar. Using vinegar is a quick way to give the sense of a pickled vegetable without waiting out the natural fermentation process. If you’re eating pickles for the health benefit, look for a naturally fermented pickle that will normally come submerged in cloudy liquid and that will bubble when the jar is opened. If you’re unsure, make your own pickles or other fermented vegetables. This recipe is an easy way to get started, but feel free to use any vegetables and spices of your liking!
Salt (1-3 tablespoons per quart of water)
Vegetables, such as:
Mustard Seeds, 1/2 tsp per quart
2-3 bay leaves
1. Breidt, F. et al (2013). Fermented Vegetables. Food Microbiology: Fundamentals and Frontiers, 4th ed. ASM Press: Washington D.C.
2. Nuraida, L. (2015). A review: Health promoting lactic acid bacteria in traditional Indonesian fermented foods. Food Science and Human Wellness, 4(2): 47-55.
3. Swain, R.M. et al. (2014). Fermented fruits and vegetables of Asia: a potential source of probiotics. Biotechnology Research International, article ID: 250424.