November 2018 Issue

Fermented Foods: Sauerkraut
By Jessica Ivey, RDN, LDN
Today's Dietitian
Vol. 20, No. 11, P. 12

An Ancient Food Taking the Spotlight in Health and Wellness

Sauerkraut is a German word meaning "sour cabbage," and this fermented food has a long and rich history of use around the world for both preservation and medicinal purposes.1 The FDA's Food Inspection Decision 196 defines sauerkraut as "the product, of characteristic acid flavor, obtained by the full fermentation, chiefly lactic, of properly prepared and shredded cabbage in the presence of not less than 2% nor more than 3% of salt. It contains, upon completion of the fermentation, not less than 1.5% of acid, expressed as lactic acid."2 Historically, claims of health benefits attributed to sauerkraut abound, but is there any evidence to back up these claims?

History and Origins
Cabbage has long been lauded for its health benefits. Cabbage commonly was found in ancient Greek and Roman gardens, as they believed it had many health benefits and used it as a cure for various illnesses. Ancient Egyptian artifacts suggest that cabbage also was used as an offering to the gods,1 and rumor has it that the Roman emperor Tiberius (AD 14–37) took salted cabbage with him on military journeys to protect the soldiers from disease.3

In Neolithic times, the people of Northern Europe enjoyed a precursor to sauerkraut—an acidic soup made from birch leaves. Sauerkraut made with cabbage goes back to the time of the German invasions during the 4th, 5th, and 6th centuries AD, when Germanic tribes applied their own processes for preparing native cabbages that they found in the area.4

The first sauerkraut recipes involved dressing the whole cabbage leaves in a sour wine or vinegar, and it wasn't until the 16th or 17th century that the current method relying on salt and the cabbage's natural bacteria was implemented.1 Sauerkraut grew in popularity in Europe, where cabbage was abundant, and it became one of the first foods produced by the manufacturing industry in the 17th century. Sauerkraut production was a source of great economic profit for towns in Germany and Alsace, a region in northeastern France.4

The celebration of the health benefits of sauerkraut came to a climax in the 1700s when it was recognized as an antiscorbutic (ie, an agent that prevents or cures scurvy). Seaman at the time were being ravaged by scurvy during long sea voyages, but the Dutch seamen remained in better health than those from other countries. This difference was credited to the large amounts of fermented cabbage carried aboard Dutch ships.5 In 1772, British Captain James Cook undertook a famous three-year voyage on which not one seaman died of scurvy. The absence of scurvy was attributed to sweetwort, a barley infusion, and also in part to sauerkraut.6 By the 1780s the British Navy had set up sauerkraut storehouses where pursers could stock up before setting sail on a long journey.4 Early Dutch and German settlers brought their traditional recipes for sauerkraut with them to the Americas, and it continued to be a popular dish, especially in areas with a high concentration of German immigrants. Following WWI, growing anti-German sentiment had many Americans avoiding sauerkraut, "a food of such unmitigated German origin"; according to a 1918 article in The New York Times, it was proposed that the name be changed from sauerkraut to "liberty cabbage."7

Since the start of the 21st century, there has been a sort of fermentation revival sweeping the country as more research reveals the potential health benefits of fermented foods.

Fermentation and Food Safety
Fermentation has been used since ancient times as a method of food preservation; the process enhances the nutritive value and flavors and reduces the toxicity of many foods.8 When making sauerkraut, the starter is the normal mixed biota of the cabbage. Adding salt inhibits the growth of gram-negative bacteria while favoring the lactic bacteria, which convert sugar into lactic acid. Fermentation will naturally stop when the maximum acidity has been reached.9 Alex Lewin, a fermentation advocate and author of two books on the subject, Real Food Fermentation: Preserving Whole Fresh Food With Live Cultures in Your Home Kitchen and Kombucha, Kefir, and Beyond: A Fun & Flavorful Guide to Fermenting Your Own Probiotic Beverages at Home, notes that sauerkraut can be stored safely at room temperature for weeks, months, or even years because it's so acidic; most harmful bacteria won't grow at a pH level below 4.6.10 Lewin says it's important to be sure that the cabbage stays submerged in the brine to prevent surface molds from forming.

According to Sandor Ellix Katz, fermentation revivalist and author of several books, including Wild Fermentation: The Flavor, Nutrition, and Craft of Live-Culture Foods, the process of fermenting vegetables is extremely versatile. He describes several variations, including sauerkraut seasoned with juniper berries or apples. When fermenting vegetables, Katz notes that a heavy ceramic crock is the ideal vessel, and a ceramic slow cooker insert also can be used. Avoid using a metal container, as the acid created during fermentation will corrode it.11

Nutrient Profile and Health Effects
A 2 T serving of sauerkraut, drained, provides 16 kcal, 0.5 g fiber, 117 mg sodium, and 2.6 mg vitamin C.12 Since sauerkraut can be high in salt, it's important to advise clients who need to watch their salt intake to limit portions of commercially prepared sauerkraut. According to Jill Nussinow, MS, RDN, a California-based dietitian and cookbook author known as The Veggie Queen, "You can make kraut with lower salt or no salt." Nussinow says that although the general ratio is 3 T salt to 5 lbs of cabbage, she has made sauerkraut with at least one-third less salt without any issues in quality. However, as salt inhibits the growth of bacteria other than lactobacilli, a lower-salt sauerkraut is more likely to turn out mushy or develop a surface mold, so clients should use caution when reducing salt.9 

Research into the health benefits of fermented foods, including sauerkraut, is fairly new. One area of interest is fermented foods' potential probiotic properties. Some of the beneficial bacteria involved in the fermentation process may still be alive at the time of consumption in "raw" fermented foods that haven't been heat treated. Consuming these "good" bacteria may help improve the balance between beneficial and harmful bacteria in the gut.13 Consuming different strains of probiotic bacteria may have an even greater benefit, as different strains have different effects. One study found 28 different strains of lactic acid bacteria present in commercially prepared sauerkraut.14 These beneficial bacteria also produce enzymes that may make fermented foods easier to digest than unfermented foods.15 If clients want to ensure they're getting probiotics in their sauerkraut, they should choose refrigerated varieties instead of pasteurized sauerkrauts off the shelf. Varieties that say, "Contains live and active cultures" on the label also should contain probiotics.

In addition to the potential benefits, some studies have raised concerns regarding possible risks of pickled foods. A meta-analysis of 60 studies found an approximately 50% increase in risk of gastric cancer in those who consumed pickled vegetables or pickled foods compared with those who didn't consume pickled vegetables or foods or those in the lowest consumption category.16 In addition, a meta-analysis of observational studies found that consumption of pickled vegetables was associated with a two-fold increased risk of esophageal cancer.17

Global Impact and Consumption
Despite the concerns, it's believed that fermented foods may play a role in helping improve food security in developing countries. The fermentation process requires little energy and reduces the need for refrigeration and expensive canning processes, allowing the introduction of more fruits and vegetables to areas where these nutrient-rich foods may not be accessible year-round.15

In Germany, sauerkraut often is served with bratwurst or alongside schupfnudel, a gnocchi-like potato dumpling. In Poland, bigos, a traditional stew, features meat cooked with vegetables and sauerkraut, and sauerkraut is one of the most popular fillings for Polish pierogi.18 Jota, a Slovenian soup, traditionally contains beans, potatoes, and sauerkraut. The French put their own spin on choucroute (the French word for sauerkraut) by adding potatoes, and it's often served with various meats and charcuterie. Visit New York and you might have a New York-style hot dog topped with spicy brown mustard and sauerkraut, or a Reuben sandwich filled with corned beef, Swiss cheese, sauerkraut, and Russian dressing.

Today, proponents of sauerkraut as a health food are suggesting better-for-you applications. Nussinow says she eats sauerkraut on top of whole grains and vegetables, and Katz suggests an elegant appetizer made by wrapping fermented cabbage leaves into rolls filled with crumbled feta or goat cheese.18 Clients can use the recipe on this page to try their hand at homemade sauerkraut, and RDs can encourage healthful applications of this popular fermented food.

— Jessica Ivey, RDN, LDN, is a dietitian and chef with a passion for teaching people to eat healthfully for a happy and delicious life. Ivey offers approachable healthful living tips, from fast recipes to meal prep guides and ways to enjoy exercise on her website, JessicaIveyRDN.com.

References
1. Farnworth ER, ed. Handbook of Fermented Functional Foods. 2nd ed. Boca Raton, FL: CRC Press; 2008:20-21.

2. CPG Sec. 585.750 sauerkraut — definition; adulteration by thrips. US Food and Drug Administration website.  https://www.fda.gov/ICECI/ComplianceManuals/CompliancePolicyGuidanceManual/ucm074636.htm. Updated November 29, 2005. Accessed August 17, 2018.

3. O'Brien J, Climenhage RJ. Fresh & Fermented: 85 Delicious Ways to Make Fermented Carrots, Kraut, and Kimchi Part of Every Meal. Seattle, WA: Sasquatch Books; 2014:10.

4. Toussaint-Samat M. A History of Food. New York, NY: Barnes & Noble Books; 1998:693-694.

5. Pederson CS, Albury MN. Bulletin: Number 824: The Sauerkraut Fermentation. Geneva, NY: New York State Agricultural Experiment Station; 1969.

6. Hess AF. Scurvy, Past and Present. Philadelphia, PA: J. B. Lippincott Company; 1920:8-9.

7. Sauerkraut may be liberty cabbage. The New York Times. April 25, 1918. https://timesmachine.nytimes.com/timesmachine/1918/04/25/96864971.pdf. Accessed August 23, 2018.

8. Swain MR, Anandharaj M, Ray RC, Rani RP. Fermented fruits and vegetables of Asia: a potential source of probiotics. Biotechnol Res Int. 2014;2014:250424.

9. Jay JM, Loessner MJ, Golden DA. Modern Food Microbiology. 7th ed. New York, NY: Springer Science & Business Media; 2005:180.

10. US Food and Drug Administration. Science and our food supply: food safety A to Z reference guide. https://www.fda.gov/downloads/food/foodscienceresearch/toolsmaterials/ucm430363.pdf. Published 2014. Accessed August 23, 2018.

11. Katz S. Vegetable fermentation further simplified. Wild Fermentation website. https://www.wildfermentation.com/category/sauerkrautrecipes/. Updated April 27, 2012. Accessed August 23, 2018.

12. US Department of Agriculture, Agricultural Research Service. USDA food composition databases. https://ndb.nal.usda.gov/ndb/. Updated April 2018. Accessed August 23, 2018.

13. Fermented foods can add depth to your diet. Harvard Health Publishing website. https://www.health.harvard.edu/staying-healthy/fermented-foods-can-add-depth-to-your-diet. Published July 2018. Accessed August 23, 2018.

14. Lu Z, Breidt F, Plengvidhya V, Fleming HP. Bacteriophage ecology in commercial sauerkraut fermentations. Appl Environ Microbiol. 2003;69(6):3192-3202.

15. Battcock M, Azam-Ali S; Food and Agriculture Organization of the United Nations Fermented Fruits and Vegetables: A Global Perspective. Rome, Italy: Food and Agriculture Organization of the United Nations; 1998.

16. Ren JS, Kamangar F, Forman D, Islami F. Pickled food and risk of gastric cancer — a systematic review and meta-analysis of English and Chinese literature. Cancer Epidemiol Biomarkers Prev. 2012;21(6):905-915.

17. Islami F, Ren JS, Taylor PR, Kamangar F. Pickled vegetables and the risk of oesophageal cancer: a meta-analysis. Br J Cancer. 2009;101(9):1641-1647.

18. Katz SE. Wild Fermentation: The Flavor, Nutrition, and Craft of Live-Culture Foods. 2nd ed. White River Junction, VT: Chelsea Green Publishing; 2016:81.