Benefits
A source of vitamin C and vitamin K
Per 100 g raw, green cabbage supplies about 37 mg of vitamin C and 76 micrograms of vitamin K, and red cabbage about 57 mg of vitamin C and 38 micrograms of vitamin K, according to USDA data. Canned sauerkraut keeps less vitamin C (about 15 mg per 100 g). These figures describe nutrient content, not a tested health effect.
Red cabbage anthocyanins and plasma antioxidant capacity
In a crossover study of 13 volunteers, red cabbage pigments (20 anthocyanins, mainly cyanidin glycosides) appeared in blood and urine along with their metabolites. Absorption was over 10% higher from fresh than from fermented red cabbage, and plasma antioxidant capacity was higher after the fresh form. There was no non-cabbage comparison.
Isothiocyanate release from raw versus cooked cabbage
In a crossover study of 12 healthy volunteers, raw cabbage released allyl isothiocyanate from its glucosinolate sinigrin quickly, as measured in urine. After microwaved cabbage, release was considerably lower and delayed, apparently relying on colon bacteria. This shows how preparation changes exposure, not a health outcome.
Sauerkraut and digestive symptom scores
In a 6-week randomized double-blind trial in 34 adults with irritable bowel syndrome, symptom scores improved with both pasteurized and unpasteurized sauerkraut, with no difference between them. There was no group without sauerkraut, so the change cannot be separated from time or expectation. The authors called the study underpowered.
Sauerkraut and gut bacteria composition
In a crossover trial of 87 healthy adults eating 100 g a day of fresh or pasteurized sauerkraut for 4 weeks each, single bacterial species shifted but the overall gut community did not, and only pasteurized sauerkraut raised serum short-chain fatty acids. Stool form and frequency did not change. The comparison was with washout periods, not another food.
Blood pressure in a cruciferous vegetable feeding trial
In a 2-week crossover trial of 18 older adults with mildly raised blood pressure, soups of blended cruciferous vegetables (25% cabbage) lowered 24-hour systolic pressure by 2.5 mmHg and triglycerides slightly versus root and squash vegetable soups. Cholesterol, glucose and inflammation markers did not differ, and cabbage was not tested alone.
Mechanism of action
Glucosinolates and isothiocyanates
Cabbage contains glucosinolates such as sinigrin, which the plant enzyme myrosinase turns into allyl isothiocyanate when raw leaves are cut or chewed. Cooking inactivates myrosinase, so less forms, later, through colon bacteria. Sulforaphane, the isothiocyanate covered on our broccoli pages, forms from a different glucosinolate, glucoraphanin.
Anthocyanins are absorbed in small amounts and metabolized
Red cabbage anthocyanins reach blood and urine both intact and as methylated, glucuronidated and sulfated metabolites. Fermenting red cabbage lowered how much was absorbed in a human crossover study.
Induction of drug-conjugating enzymes
In a controlled diet study in 10 healthy people, a diet rich in cabbage and Brussels sprouts sped up the glucuronidation and clearance of acetaminophen and lowered blood levels of oxazepam, a sign that these vegetables can switch on conjugation enzymes in people.
Fermentation adds lactic acid bacteria and their products
Lacto-fermented sauerkraut carries lactic acid bacteria such as L. plantarum and L. brevis; pasteurization kills them. In the sauerkraut trials, pasteurized sauerkraut had similar or larger effects than fresh, so the authors suggested that non-living components, rather than live bacteria, drove the changes.
Clinical trials
Randomized, double-blind, 6-week pilot comparing pasteurized with unpasteurized lacto-fermented sauerkraut added to the usual diet, with follow-up at week 8. (Nielsen et al. 2018, Food Funct)
34 Norwegian adults with irritable bowel syndrome (15 pasteurized, 19 unpasteurized).
IBS Symptom Severity Score fell in both groups (mean change -38.6 pasteurized, -57.0 unpasteurized; P < 0.04), with no difference between groups. Gut bacterial composition changed, and sauerkraut lactobacilli were found more often in the unpasteurized group. With no sauerkraut-free comparison and an underpowered sample, the result does not show that sauerkraut beats no sauerkraut.
Randomized crossover trial of 100 g a day of fresh or pasteurized commercial sauerkraut for 4 weeks each, each after a 4-week washout without fermented foods; shotgun metagenomics and short-chain fatty acids. (Schropp et al. 2025, Microbiome)
87 healthy adults aged 21 to 69 in Germany (84 completed).
Single bacterial species changed, more with pasteurized sauerkraut, but there was no global shift in gut community composition. Only pasteurized sauerkraut raised serum short-chain fatty acids; fecal butyric acid fell after fresh sauerkraut. Stool form and frequency were unchanged, and both products were well tolerated. There was no non-sauerkraut comparison food.
Randomized crossover trial of 100 g a day of fresh and of pasteurized sauerkraut for 4 weeks each, after 4-week washouts; values compared before and after each phase with regression models. (Schropp et al. 2026, Eur J Clin Nutr)
87 healthy adults (the same trial as the microbiome report).
Both forms were associated with a small fall in systolic blood pressure. Gut barrier markers did not change, and inflammation and blood sugar markers changed only in some subgroups (by age, fiber intake and, less so, BMI and sex). The authors concluded that 4 weeks of daily sauerkraut was not linked to an appreciable systemic health benefit in healthy people.
Randomized controlled crossover trial, participants blinded to which soup was active: about 300 g a day of cruciferous vegetables (40% broccoli, 25% cauliflower, 25% cabbage, 10% kale) versus root and squash vegetables, 2 weeks each with a 2-week washout. (Connolly et al. 2024, BMC Med)
18 adults (median age 68, 16 women) in Australia with systolic blood pressure of 120 to 160 mmHg.
24-hour systolic pressure fell 2.5 mmHg more than with the control soup (P = 0.002), and triglycerides fell 0.2 mmol/L more (P = 0.047). Total, LDL and HDL cholesterol, glucose, hsCRP, IL-6 and arterial stiffness did not differ between soups, and nighttime aortic diastolic pressure was 2.9 mmHg higher with the crucifer soup. No adverse events. A small, short trial of a crucifer blend, not cabbage alone.
Randomized crossover study of fresh and fermented red cabbage, with anthocyanins measured in plasma and urine and plasma antioxidant capacity by photochemiluminescence. (Wiczkowski et al. 2016, Food Chem)
13 volunteers.
Red cabbage contained 20 anthocyanins, mainly cyanidin triglucosides; 18 native forms and 12 metabolites appeared in body fluids. Bioavailability was over 10% higher from fresh than from fermented red cabbage, and plasma antioxidant capacity was higher after the fresh form. A short absorption study with no non-cabbage control.
Controlled feeding study with three 10-day diets in sequence (control, cabbage plus Brussels sprouts, control again), with oxazepam on day 7 and acetaminophen on day 10. (Pantuck et al. 1984, Clin Pharmacol Ther)
10 healthy subjects.
On the vegetable diet, acetaminophen AUC fell 16% and its clearance rose 17%, mainly through more glucuronidation, and oxazepam AUC fell 17%, though oxazepam half-life did not change. Acetaminophen measures moved back toward control on the second control diet. The diet combined cabbage with Brussels sprouts.
Historical uncontrolled case series of fresh raw cabbage juice, with ulcer healing judged by x-ray and gastroscopy and compared only with healing times published for other patients. (Cheney et al. 1949, Calif Med)
13 patients with peptic ulcer (7 duodenal, 6 gastric).
Average crater healing time was 10.4 days (duodenal) and 7.3 days (gastric), versus 37 and 42 days reported in the literature for standard therapy. With no concurrent control group, these comparisons cannot show that the juice caused faster healing. Ulcers need medical care.
Historical double-blind comparison of concentrated cabbage juice with a placebo look-alike, ulcer craters followed by repeated x-rays over 22 days. (Cheney et al. 1956, Calif Med)
San Quentin Prison inmates with an x-ray diagnosed ulcer crater (number not given in the PubMed abstract).
The authors reported a favorable result for the juice, but the abstract gives no patient numbers, healing rates or statistics, so the result cannot be judged from it, and the study predates modern trial standards. It is not evidence for use in healthy people and not a substitute for medical care.