Why is Sauerkraut So High in Vitamin C?

January 9, 2026 •

4 min read

An estimated two million deaths were caused by scurvy on long sailing voyages before sailors like Captain James Cook learned that fermented cabbage could prevent it. So, why is sauerkraut so high in vitamin C, and how does this simple food have such a powerful nutritional punch?

Quick Summary

The high vitamin C content in sauerkraut is due to the fermentation process, which preserves the nutrient and makes it more bioavailable than in raw cabbage. This happens because the anaerobic, low-heat conditions prevent oxidation, safeguarding the delicate vitamin.

Key Points

Fermentation preserves vitamin C: The anaerobic, low-heat environment of lactic acid fermentation protects the delicate vitamin C from oxygen and heat-induced destruction.
Increases nutrient bioavailability: The process enhances the body's ability to absorb vitamin C and other nutrients by reducing antinutrients.
Raw is best for maximum benefits: Unpasteurized sauerkraut, found in refrigerated sections, contains higher levels of vitamin C and beneficial probiotics.
Boosts immune system: The combination of probiotics and high vitamin C helps strengthen the body's immune response.
Improves digestive health: Sauerkraut provides both fiber and live probiotics that aid in digestion and support a healthy gut microbiome.
Historically significant: For centuries, sauerkraut was a vital food source that prevented scurvy on long sea voyages, proving its reliability as a vitamin C source.

The Science Behind Sauerkraut's Vitamin C Content

Sauerkraut's reputation as a vitamin C powerhouse stems from the unique process of lactic acid fermentation. While raw cabbage is a good source of vitamin C on its own, fermentation changes its chemical landscape in a way that is highly beneficial for nutrient preservation. The key is a multi-layered effect involving preservation from oxidation, increased bioavailability, and a historically reliable preservation method.

Fermentation: A Natural Defense Against Nutrient Loss

The most significant factor explaining why is sauerkraut so high in vitamin C is the fermentation environment itself. Vitamin C (ascorbic acid) is a notoriously delicate nutrient, highly sensitive to heat, light, and, most importantly, oxygen. The fermentation process is anaerobic, meaning it takes place in a low-oxygen environment. By sealing the shredded cabbage under its own natural juices and brine, oxygen exposure is minimized. This prevents the oxidation that would normally degrade the vitamin during a typical cooking process.

The process begins when naturally occurring lactic acid bacteria (LAB), such as Lactobacillus, break down the sugars in the cabbage. This creates lactic acid, which further lowers the pH of the kraut. This acidic environment acts as a natural preservative, inhibiting the growth of harmful bacteria while creating a stable, oxygen-free zone that shelters the vitamin C.

Bioavailability: Getting More Out of Every Bite

Beyond simply preserving the vitamin, fermentation enhances the body's ability to use it. Research indicates that the fermentation process can increase the bioavailability of nutrients, making them easier for the body to absorb. This is due in part to the reduction of antinutrients, such as tannins and phytates, which can otherwise inhibit the absorption of certain vitamins and minerals. The probiotics produced during fermentation also support overall gut health, which improves the gut's ability to absorb nutrients more efficiently.

The Historical and Practical Significance

For centuries, long before refrigeration, sauerkraut was a winter staple in many cultures because of its long shelf life and nutritional value. The ability to store this vitamin C-rich food through the cold winter months was a survival strategy. This historical context highlights its practical importance and confirms its reliable role as a source of vitamin C.

Raw vs. Pasteurized Sauerkraut: A Key Distinction

Not all sauerkraut is created equal, and the processing method is critical when it comes to vitamin C content. Here’s a breakdown of the differences.


Feature	Raw, Unpasteurized Sauerkraut	Pasteurized Sauerkraut
Processing	Cabbage fermented naturally with salt and spices. Not heated.	Cabbage is heated to high temperatures to kill bacteria and extend shelf life.
Vitamin C Content	Retains high levels of vitamin C due to low-heat processing.	May contain less vitamin C, as some is destroyed by heat.
Probiotics	Contains billions of live, beneficial lactic acid bacteria.	Beneficial bacteria are killed during the heating process.
Shelf Life	Shorter shelf life; must be kept refrigerated.	Extended shelf life; often sold on unrefrigerated shelves.
Flavor	Complex, tangy flavor profile with more nuanced notes.	Milder, sometimes more acidic flavor.
Texture	Crunchy and firm.	Softer, less crisp texture.

For those seeking the maximum health benefits, including a high dose of vitamin C, opting for raw, unpasteurized sauerkraut from the refrigerated section of the store is the best choice.

The Health Benefits Beyond Vitamin C

While its high vitamin C is a significant benefit, sauerkraut offers a range of other nutritional advantages due to its fermentation. These include:

Enhanced Immune Function: The probiotics and vitamin C work together to strengthen the immune system. A healthy gut microbiome improves the body's ability to fight off infections.
Improved Digestion: The fiber and live bacteria aid in digestion by promoting a healthy balance of gut flora. This can help with issues like constipation and diarrhea.
Source of Antioxidants: Fermentation increases the availability of other beneficial compounds and antioxidants, which help protect the body from damage caused by free radicals.
Low in Calories: Despite its nutrient density, sauerkraut is low in calories, making it a great addition to a balanced diet.
Source of Vitamin K2: Sauerkraut is one of the few plant-based sources of vitamin K2, which is essential for bone and heart health.

How to Make Your Own High-Vitamin-C Sauerkraut

Making your own sauerkraut is a straightforward process that ensures you get the freshest, most nutrient-dense product. The key is a clean, anaerobic environment. Here are the basic steps:

Chop: Finely shred a head of fresh cabbage. For a single batch, use about 5 pounds of cabbage.
Salt: Mix the shredded cabbage with a precise amount of non-iodized salt (approximately 1.5 tablespoons per 2.5 pounds of cabbage). Massaging the cabbage helps draw out its natural liquid.
Pack: Tightly pack the cabbage into a clean, sterile fermentation crock or glass jar, ensuring it is submerged beneath the brine. Use a weight to keep the cabbage submerged and prevent air exposure.
Ferment: Store the container in a cool, dark place for 2 to 6 weeks, or until it reaches your desired level of sourness. Regularly check to ensure the cabbage remains submerged.
Store: Once fermented, transfer the sauerkraut to the refrigerator to slow the fermentation and preserve the final flavor and nutrient content.

Conclusion: A Traditional Food with Modern Relevance

Sauerkraut's impressive vitamin C content is a testament to the power of traditional food preparation methods. The simple, low-heat process of lactic acid fermentation protects the delicate vitamin from oxidation, while also increasing its bioavailability and adding a host of other beneficial nutrients and probiotics. From preventing scurvy on ancient sea voyages to boosting modern immune systems, sauerkraut has proven its nutritional worth. Choosing raw, unpasteurized sauerkraut ensures you reap the maximum benefits from this humble but powerful food, preserving a rich source of vitamin C for your health and wellbeing.

For further reading on the fermentation process, you can explore detailed resources from the National Center for Biotechnology Information.

Frequently Asked Questions

Yes, cooking or heating sauerkraut can destroy a significant portion of its vitamin C content, which is sensitive to heat. To preserve the maximum amount of vitamin C, it is best to consume raw, unpasteurized sauerkraut.

No, only raw, unpasteurized sauerkraut is reliably high in vitamin C. Pasteurized versions, which are heated to extend shelf life, have lost some of this nutrient during processing. Always check the label and look for refrigerated versions.

Fermentation protects vitamin C by creating an anaerobic (oxygen-free) and acidic environment. Since vitamin C degrades rapidly when exposed to oxygen, this process effectively seals the nutrient from degradation.

Homemade sauerkraut can have very high vitamin C levels, especially if you start with fresh, high-quality cabbage and ferment it correctly. Raw, artisanal store-bought versions are also excellent, but commercial, canned varieties may have reduced vitamin content.

While raw cabbage contains vitamin C, sauerkraut's fermentation process preserves the nutrient better and can make it more bioavailable. In some studies, fermented cabbage products have shown even higher ascorbic acid content than the fresh vegetable.

Historically, yes. The high and stable vitamin C content of sauerkraut made it an effective preventative for scurvy, a disease caused by vitamin C deficiency, for sailors on long sea voyages.

Sauerkraut is a type of fermented cabbage, but not all fermented cabbage is sauerkraut. Sauerkraut is specifically fermented with salt in an anaerobic environment, while other fermented cabbage dishes like kimchi include additional spices and ingredients.