Foods we love: Sauerkraut
This living fermented food contains beneficial microbes, fiber, and phytochemicals that support gut and metabolic health.
With a distinctly tangy-salty taste and pleasant crunch, sauerkraut is a perfect way to add nuance, brightness, and texture to all sorts of dishes. And in addition to its culinary appeal, it’s also a potent source of nutrition.
The name sauerkraut translates to “sour cabbage” in German. It is traditionally made by combining shredded cabbage with salt and allowing the mixture to undergo fermentation by the naturally occurring bacteria present on the cabbage leaves and in the surrounding air.
Specifically, sauerkraut is made via lactic acid fermentation (an age-old method of food preservation that’s also used to turn milk into yogurt), and it involves various strains of Leuconostoc and Lactobacillus bacteria. The controlled growth of these live microbes, along with the enzymatic transformation of multiple nutrients and other compounds within cabbage, is what’s able to turn an average veggie into a living food with a diverse nutritional profile.
In addition to being a source of potentially probiotic lactic acid bacteria, which may support a healthy gut microbiome (and, in turn, promote metabolic health), sauerkraut contains beneficial byproducts of fermentation such as short-chain fatty acids and vitamin K2. The fermentation process may also break down phytochemicals, such as glucosinolates in cabbage, into molecules with antioxidant and anti-inflammatory potential and enhance the overall bioavailability of nutrients. Sauerkraut is also unlikely to spike blood sugar, as it contains just 27 calories and 6 grams of carbs per cup, along with 4 grams of fiber.
The Metabolic Health Benefits of Sauerkraut
To understand why sauerkraut is such a promising food, it’s essential to have a rough understanding of the role that the gut microbiome plays in metabolic function.
The gut microbiome is a collection of trillions of bacteria and other microorganisms that reside in your gut (or large intestines). When these microbes break down food, they produce metabolites that communicate with your body’s cells and influence everything from the secretion of glucose-regulating hormones to inflammatory reactions.
For everything to run optimally (i.e., your gut bugs to pump out metabolites that promote helpful—not harmful—metabolic processes in the body), your gut must be in balance. That is, it needs to contain a diverse array of beneficial microbes. But a lot of things can negatively impact this balance. For example, a low-fiber, highly processed diet can quash microbial diversity since good microbes require fiber to survive and multiply; and certain medications like antibiotics indiscriminately kill both good and bad bacteria.
Chronic inflammation is one potential consequence of an unbalanced gut microbiome, and it’s been associated with insulin resistance and metabolic disorders such as diabetes and obesity. Additionally, research has shown that specific changes in gut microbiota composition and decreased microbial diversity are linked to increased fat mass, pro-inflammatory biomarkers, and insulin resistance.
The good news: Consuming probiotics (which can help repopulate the gut with good microbes) and fiber (which can serve as a food source for those good bugs) may help bring your gut back into microbial balance. And that’s where sauerkraut comes in.
Sauerkraut contains potentially probiotic microorganisms, such as lactic acid bacteria (LAB), which may help repopulate a depleted gut. Preliminary animal research suggests that LAB may lead to changes in the gut microbiome that support immune function and reduce inflammation. More recently, a study from top gut microbiome researchers at Stanford University found that people who gradually increased their consumption of fermented foods (including sauerkraut) to six servings per day for 10 weeks experienced a boost in gut microbial diversity that was simultaneously associated with reduced biomarkers of inflammation—including the inflammatory protein interleukin 6, which is associated with Type 2 diabetes. This suggests that consuming more fermented foods like sauerkraut, kimchi, kvass, kefir, and yogurt may be one way to help curb risk for chronic metabolic diseases.
Fermented foods also contain byproducts of fermentation (sometimes referred to as “postbiotics”) called short-chain fatty acids (SCFAs) in higher amounts than non-fermented foods, according to research. SCFAs such as butyrate and propionate are produced when beneficial microbes metabolize various food components during fermentation. They’re also made by good gut microbes in your body after they break down and ferment dietary fiber. Research suggests that SCFAs suppress pro-inflammatory pathways, support a healthy gut barrier (which also plays a role in suppressing chronic inflammation), and promote glycemic control by stimulating the secretion of gut hormones such as glucagon-like peptide 1 (GLP-1), which improves insulin sensitivity and helps promote stable blood sugar.
However, most research on SCFAs focuses on the ones produced by your gut microbes after eating fiber—and, according to the experts, much more research is needed to determine the perks of consuming SCFAs directly from fermented foods. But it’s a promising area of study. Plus, sauerkraut also provides fiber, some of which appear to act as a prebiotic, meaning it is fermented or broken down by beneficial microbes in the gut and may promote the secretion of SCFAs. For example, research shows that cellulose—a type of dietary fiber present in cabbage and sauerkraut—is broken down into SCFAs by the bacterial species Bacteroidetes.
Finally, cruciferous vegetables like cabbage contain sulfur-containing phytochemicals called glucosinolates. These are broken down into several beneficial byproducts—including indole-3-carbinol, ascorbigen, allyl isothiocyanate, and sulforaphane—that activate crucial antioxidant and anti-inflammatory processes. Sulforaphane, for example, is known to activate the NRF2 pathway (which activates genes that generate our body’s antioxidant defenses) and inhibit the NF-κB pathway (which normally turns on pro-inflammatory genes). Research suggests these sulforaphane-induced effects may, in turn, support healthy blood sugar regulation and exert an overall anti-diabetic effect.
Tips for Buying, Using, and Making Sauerkraut
Not all sauerkraut is created equal. Knowing what to look for on labels can help you reap the maximum health (and flavor) benefits—and storing and using sauerkraut properly helps preserve those perks. Here’s what you need to know, plus a nutritious DIY recipe:
- Choose raw, fermented, unpasteurized sauerkraut. For sauerkraut—or any fermented veggie—to have potential probiotic benefits, it must retain its live microorganisms. These beneficial microbes are killed during pasteurization (a type of heat treatment), so always look for fresh sauerkraut (sometimes labeled “contains live and active cultures”) in the refrigerated section. Jarred or canned shelf-stable varieties have typically been pasteurized. However, pasteurized varieties still provide dietary fiber.
- Familiarize yourself with some good brands. Cleveland Kraut Classic Caraway is one of our favorite products from Whole Foods, and it uses only cabbage, kosher salt, and caraway seeds. Other brands that stay true to the traditional sauerkraut-making process and don’t feature added sugars or preservatives are Wildbrine, Farmhouse Culture, Bubbies, and Hawthorne Valley.
- Experiment with different flavors. While green cabbage and salt are the only two ingredients essential for sauerkraut, the brands above offer options with nutritious flavor-boosters like caraway seeds, apple, red cabbage, beets, carrots, ginger, turmeric, and jalapenos. If you’re not a fan of plain sauerkraut, you may love one of these variations.
- Skip the sauerkraut made with vinegar. It’s not real sauerkraut. While this mimics the trademark sour flavor of traditional sauerkraut (which comes from the fermentation process), vegetables pickled in vinegar are not fermented and do not come with any of the microbial benefits. Like pasteurized sauerkraut, however, these vinegar-based options still provide dietary fiber from cabbage.
- Don’t cook your sauerkraut. Live probiotic cultures are destroyed when heated, so you may be wiping out many of sauerkraut’s potential health benefits. Instead, add sauerkraut to dishes after they’ve been cooked. Check out the suggestions below.
- Once opened, a jar of fermented sauerkraut can generally stay fresh in the refrigerator for 4-6 months. Keep in mind that if you’re double-dipping or eating straight from the jar, you may introduce new bacteria that cause it to spoil faster. Keep that jar sealed tightly, too, to prevent sauerkraut from drying out.
- Try making your own sauerkraut. This recipe from Minimalist Baker features a fun twist on traditional kraut with cabbage and additional flavor-boosting ingredients such as beets, carrots, ginger, garlic, and turmeric. Prep is simple and involves chopping, massaging the ingredients, and transferring them to a sterilized jar (cleanliness is vital), but the fermentation process can take up to two weeks.
Ideas For Eating Sauerkraut
Sauerkraut is traditionally served alongside bratwurst or piled onto Reuben sandwiches, but this fermented veggie can do far more than playing second fiddle to processed meats. Below are some delicious ways to use it in its raw form:
- Make it your go-to condiment: Instead of sugary, highly processed condiments, add sauerkraut to lettuce wraps and bunless burgers to boost flavor and crunchy texture.
- Enjoy it as a low-carb side: Eat sauerkraut in place of starchy sides like rice and potatoes. Its tangy kick complements the richness of chicken thighs, pork, and steak. You can even use it to replace chips—it’s salty and crunchy, minus the empty carbs.
- Use it as a zesty salad topper: Top your salads with tangy sauerkraut and a drizzle of olive oil for a unique, nutritious spin on salad dressing. You’ll get that same tangy bite you’d typically get from vinegar, but with additional microbial benefits.
- Spice up your guacamole: Put a spin on guac by mashing up avocado with sauerkraut—the tangy kraut can take the place of the lime. Eat with seed crackers for a low-carb snack. We recommend a spicy sauerkraut made with jalapenos for an extra kick.
- Make a creamy low-carb dip: Chop up some sauerkraut and mix with cream cheese for a quick DIY dip that you can use with flaxseed crackers or veggie slices.
- Add to a cheese platter: Cheese and tangy sauerkraut make a great match. Slice up some gouda and gruyere and serve alongside sauerkraut, olives, apple slices, nuts, and Flackers for a healthy cheese board.
- Add it to tuna or salmon salad: Instead of using relish or celery, chop up sauerkraut and add it to tuna salad and a bit of avocado oil-based mayonnaise. Or, for an elevated spin on tuna salad (and an extra hit of omega-3s), try this salmon salad with mayo, sauerkraut, and artichoke hearts from Levels advisor Mark Hyman, MD.
- Top a cauliflower rice bowl: Sauerkraut adds another flavor dimension to plant-based meals. Try this cauliflower rice bowl with red cabbage, garbanzo beans, tamari, tahini, and sauerkraut created by Casey Means, MD, Levels Chief Medical Officer.
- Top a baked sweet potato: Load up a baked sweet potato with sauerkraut, pulled pork (minus the bbq sauce), a dollop of sour cream, and a sprinkling of scallions.
- Make a reverse wrap: For a quick lunch or snack, layer a slice of deli turkey, a slice of cheese, and a nice little pile of sauerkraut, then roll it all up and eat.
- Add it to eggs: Pile sauerkraut onto scrambled, fried, or poached eggs. The richness of the eggs (particularly with a good runny yolk) pairs perfectly with the salty-sour crunch of sauerkraut.
