Fermented foods are becoming increasingly popular in health food circles. Indeed, their benefits are now regularly extolled by everyone from omnivores and vegans to proponents of the Paleo diet. In order to understand what has all of these nutritionists and dietitians so excited, one must first learn about fermentation and what fermented foods are.
Fermentation, in its most simple form is “a chemical change with effervescence.” (1) For a more detailed definition, Merriam-Webster defines fermentation as “an enzymatically controlled anaerobic breakdown of an energy-rich compound (as a carbohydrate to carbon dioxide and alcohol or to an organic acid); broadly : an enzymatically controlled transformation of an organic compound.” In simple terms, it is a chemical change that happens when an organism breaks down a carbohydrate into an alcohol or acid.
Fermented foods are those that have undergone this chemical change, and many of them have incredible health-affirming benefits. However, the most widely recognized fermented food is probably beer! It is a prime example of fermentation converting sugars into ethanol and resulting in an alcoholic beverage. Wine and hard ciders are further examples of this. But despite their popularity, these types of fermented foods are only the tip of the iceberg when it comes to what is available, and they certainly don’t offer the health benefits of other fermented foods.
Natural fermentation has been taking place since ancient times. (2) One of the earliest examples of recorded human-assisted food fermentation took place in China over 7000 years BC, where a fermented rice and fruit based alcoholic beverage was brewed. Traces of ancient fermented foods have also been found in areas stretching from Iran to pre-Hispanic Mexico. Currently, every region on earth produces some sort of fermented food.
Several different food groups can serve as a fermentation base. Beer is grain-based (wheat), while wine and cider are fruit based (grapes, apples). Fermented foods can also be derived from vegetables, beans, dairy, honey, fish, meat or tea. Some foods are ubiquitous, while others remain local specialties. Examples of differently based fermented foods that are more familiar include sauerkraut (cabbage), soy sauce (soy bean), yogurt (milk), shrimp paste (fish), chorizo (meat), and Kombucha (tea).
What are the health benefits of fermented foods?
The benefits of fermented foods are closely tied to those of http://www.thecandidadiet.com/guide-to-probiotics/ probiotic foods and supplements. (3) Probiotics are beneficial intestinal flora, or healthy gut bacteria. There are over 500 species indigenous to the human digestive and urogenital tracts. Probiotics are supplements or foods that provide bacteria that are the same or similar to those already found in the body. They are credited with improving digestive health, relieving digestive and urogenital disorders, strengthening immunity and even aiding skin conditions. Recent research is also establishing links between gut-bacteria and the central nervous system; there is emerging evidence that microbes in the digestive system can affect mood and behavior.
Although not all fermented foods provide probiotics, fermented vegetable and dairy products often do. The dairy products include yogurt and kefir. Yogurt is produced with the addition of Lactobacillus bulgaricus and Streptococcus thermophiles cultures to dairy, soy or coconut milk. In order to receive a “Live and Active Cultures” (LAC) seal from the National Yogurt Association, yogurt must have at least 100 million cultures per gram at the time of manufacture. These live bacteria also serve to break down the lactose in milk, making fermented dairy products tolerable for those who otherwise are sensitive to, or cannot digest lactose.
During food fermentation, carbohydrates (starches) are converted to organic acids, alcohols or carbon dioxide using bacteria, yeast or both in an environment devoid of oxygen. For this reason, fermented foods are considered by some to be pre-digested. Foods that are pre-digested have more available nutrients, along with beneficial enzymes. This allows for faster and easier digestion and greater absorption of vitamins and minerals.
There is a long list of fermented foods, and they all provide different benefits. (4) We have already discussed yogurt and kefir, but there are lots of other vegetable and bean-based fermented foods that have wonderful health benefits.
Vegetable-based
- Sauerkraut
Fermented cabbage produced by lactic acid bacteria. Low in calories, high in minerals and vitamins including calcium, magnesium, vitamins K, C and B. Provides probiotics in the form of lactobacilli.
- Kimchi
Korean fermented vegetables, mainly Napa cabbage but can also include radish, cucumber or scallion. Preparations also include garlic, chilies and onions making the dish very spicy. Low in calories, high in dietary fiber, and numerous vitamins and minerals including iron, calcium, A and B vitamins. Provides probiotics in the form of Lactobacillus kimchii.
Bean-based
- Natto
Soybeans fermented with Bacillus subtilis. Traditional Japanese food contains large amounts of Vitamin K. Also touted for anti-cancer and anti-clotting properties. Slimy, with a strong odor due to pyrazine, so an acquired taste for some. Be aware that most soy these days is genetically modified, but it is still possible to find organic, non-GMO Natto.
- Tempeh
Fermented soybean cake originating from Indonesia. High in protein, vitamin B12 (depending on preparation) and fiber. Pre-digestion through fermentation reduces compounds associated with gas and indigestion. Fermentation also makes soy minerals more absorbable by the body.
Fermented food cautions
Fermented foods can be a healthy dietary addition, but there are a few risks to be aware of.
- All fermented foods should be produced in food grade containers. This is not a problem for commercial preparations, but many health and nutrition websites advocate home fermentation. In addition to avoiding common trash cans and buckets, all containers should be well washed before filling.
- Store-bought fermented foods. The fermented foods that you buy in the supermarket will not contain live cultures unless they specifically say so on the container. Purchasing a starter culture and making your own is always best! This applies particularly to yogurt and kefir – if you make your own at home you can run the fermentation process a little longer and reduce the lactose content of the dairy even further.
Do fermented foods have a place at the table in a healthy diet? The research suggests these foods certainly should.
References and Further Reading
1. About.com. “What is fermentation?”. http://chemistry.about.com/od/lecturenoteslab1/f/What-Is-Fermentation.htm.
2. TheCandidaDiet.com. “The History Of Probiotics”. http://www.thecandidadiet.com/the-history-of-probiotics/.
3. WebMd. “The Truth About Probiotics And Your Gut”. http://www.webmd.com/digestive-disorders/probiotics-10/default.htm.
4. Wikipedia. “List of fermented foods”. http://en.wikipedia.org/wiki/List_of_fermented_foods
