Kohlrabi is a cabbage that grows its stem into a ball. It belongs to the same species as broccoli, cabbage, kale and Brussels sprouts, Brassica oleracea, and breeders selected it for a swollen, nearly round stem. The bulb is not a root, and the name, German for cabbage-turnip, only reflects its turnip-like shape.
A cup (135 g) of raw kohlrabi has 36 calories and 83.7 mg of vitamin C, 93% of the daily value. Gram for gram, only 11 of the 99 foods on this site have more vitamin C. Lab work on nine kohlrabi tissues found that the leaves are rich in glucoraphanin, the precursor of broccoli’s sulforaphane, while the bulb holds more of a related compound, glucoerucin.
Almost nobody has fed kohlrabi itself to people and tracked their health. Most of the research below is on cruciferous vegetables as a group, or on kohlrabi extracts, cells and rats, and each card says which. Both the bulb and the leaves are edible, and there is a variety called Haakh that has no swollen stem and is grown for its leaves.
Health benefits of kohlrabi
The top findings from 18 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Lower total cholesterol, but not LDLIn 9 trials of Brassica vegetables as a group, total cholesterol fell. LDL, triglycerides and blood sugar did not change. Kohlrabi was not named.
- ★Slightly lower blood pressureIn 18 older adults with mildly raised blood pressure, cruciferous vegetables lowered the 24-hour top number by 2.5 mm Hg versus root and squash vegetables. Each diet lasted only 2 weeks and gave about 300 g a day, and kohlrabi was not tested alone.
- ★Shifted gut bacteria toward butyrate producersIn 55 volunteers who finished, three weeks of fermented vegetables, including fermented kohlrabi, shifted gut bacteria toward more species that make butyrate. Kohlrabi was eaten with carrots and kimchi.
- Population studyLinked to a lower risk of dyingIn China, the highest intake of cruciferous vegetables, as a group, went with a 22% lower risk of dying. In Japan, the top fifth had an 11 to 14% lower risk over about 17 years.
- Population studyLinked to lower colorectal cancer riskPeople who ate the most cruciferous vegetables had an 18% lower risk of colorectal cancer. In prospective studies alone the link was borderline, and kohlrabi was not named.
All 18 studies, strongest evidence first
Brassica vegetables, the group kohlrabi belongs to, lowered total cholesterol in trials, but not LDL, triglycerides or blood sugar
Meta-analysis of 9 randomized trials (548 people) of Brassica vegetables as a group; the abstract does not name kohlrabi. Only total cholesterol fell significantly, while LDL, HDL, triglycerides, fasting blood sugar and HbA1c did not change. The authors call for more high-quality studies.
About 300 g a day of cruciferous vegetables for 2 weeks lowered 24-hour systolic blood pressure by 2.5 mm Hg compared with root and squash vegetables
Randomized crossover trial in 18 older Australian adults with mildly raised blood pressure, testing cruciferous vegetables as a group, not kohlrabi alone. Daytime pressure fell 3.6 mm Hg and triglycerides 0.2 mmol/L. It was small and each diet lasted only 2 weeks.
Three weeks of fermented vegetables, including fermented kohlrabi, shifted gut bacteria toward more butyrate-producing species
Study in 65 volunteers, of whom 55 finished, who ate a mix of fermented carrots, kohlrabi and kimchi, so the effect of kohlrabi alone cannot be separated. Results differed between healthy people, people with constipation and people recovering from antibiotics. Food diaries also showed less sugar eaten.
In an umbrella review of cruciferous vegetables, only gastric, lung and endometrial cancer and all-cause mortality had suggestive links to lower risk
Review of 41 meta-analyses covering 303 observational studies and about 13.4 million people. Sixteen more links were supported by weak evidence, and the authors say substantial uncertainty remains. It covers cruciferous vegetables as a group.
Each extra 100 g a day of cruciferous vegetables went with a 10% lower risk of dying in an umbrella review of meta-analyses
Review of 57 articles covering 24 health outcomes in people. Higher intake was also linked to lower risk of cancers and depression, but 68% of the evidence was of low quality. The authors note warfarin resistance with vitamin K-rich broccoli and advise caution for people allergic to the Brassica genus.
Chinese adults who ate the most cruciferous vegetables had a 22% lower risk of dying than those who ate the least
Two Shanghai cohorts with 134,796 adults, including 3,442 deaths among women and 1,951 among men. The link was mainly with cardiovascular deaths, not cancer deaths. It covers cruciferous vegetables as a group, from food questionnaires.
Japanese adults in the top fifth of cruciferous vegetable intake had an 11 to 14% lower risk of dying over about 17 years
Cohort of 88,184 people aged 45 to 74, with 15,349 deaths over a median 16.9 years. Lower cancer deaths showed only in men, and lower heart disease and stroke deaths only in women. It covers cruciferous vegetables as a group.
People who ate the most cruciferous vegetables had an 18% lower risk of colorectal cancer
Meta-analysis of 24 case-control and 11 prospective studies of cruciferous vegetables as a group; cabbage and broccoli analyzed on their own gave similar results, and kohlrabi was not named. In the prospective studies alone the link was borderline, and case-control studies depend on people recalling past diet.
Pooled cohorts linked the most cruciferous vegetables to a 16% lower risk of type 2 diabetes
Meta-analysis of prospective cohorts that also covered citrus fruit, with 16,544 diabetes cases among 306,723 people; four cohorts covered cruciferous vegetables as a group (risk 0.84, range 0.73 to 0.96). The results varied between studies, and the authors say more large studies are needed.
US adults who ate the most cruciferous vegetables had a 16% higher risk of type 2 diabetes
Three US cohorts with 200,907 people and 16,567 cases. Those in the top fifth for glucosinolates, the compounds cruciferous vegetables are known for, had a 19% higher risk. The authors ask for repeat and biomarker studies, and a link is not proof of cause.
A phenolic-rich kohlrabi extract cut fasting blood glucose by 64% within 7 days in diabetic rats
Study in rats, not people. Rats made diabetic with streptozotocin received an extract of kohlrabi, and their lipid profile, HbA1c and liver and kidney markers also improved. It tested an extract, not the vegetable on a plate.
Red kohlrabi extract held twice the phenolics of green kohlrabi and blocked a diabetes-related enzyme more strongly in the lab
Test-tube and cell study using mouse immune cells grown in a dish. Methanol extracts of both blocked the enzyme PTP1B (IC50 207 and 287 µg/mL for red and green), and the red extract also did better in the antioxidant and anti-inflammatory tests. No animal or person was fed kohlrabi.
Kohlrabi sprouts in the diet of rats did not change thyroid hormones but affected liver function
Study in rats, not people, using two models of an underactive thyroid (iodine deficiency and a drug). TSH, fT3 and fT4 stayed the same and the sprouts did not prevent thyroid damage, while white blood cell counts fell and liver function was adversely affected, which the authors link to a higher glucosinolate intake. Sprouts are not the bulb.
Kohlrabi sprouts and bulbs were less toxic to normal cells than to cancer cells in a dish
Lab study on two cancer cell lines (SW480 and HepG2) and normal BJ cells. Sprouts killed SW480 cells more by necrosis (56.4%) than by apoptosis (34.1%), while bulbs favored apoptosis. Light and sprouting time also changed the phenolic and progoitrin levels.
Juices of cruciferous vegetables, kohlrabi among them, blocked a cooked-meat mutagen in bacteria, though heating partly reduced the effect for kohlrabi
Test-tube study of the juices of 28 fruits and 34 vegetables against a mutagen formed in cooked meat (IQ), measured in Salmonella bacteria. Strong to moderate activity was found for all cruciferous vegetables except Chinese cabbage, and the abstract does not give a separate figure for kohlrabi. This is a bacterial test, not a study in people.
Brief heating of kohlrabi raised isothiocyanate formation, while boiling leached glucosinolates into the cooking water
Lab study of kohlrabi, white cabbage and red cabbage. A short spell of heat switched off a protein that steers the reaction toward less active compounds, and the enzyme myrosinase was inactivated soon after. Heating to 99°C broke glucosinolates down into nitriles. This is chemistry, not a study in people.
Kohlrabi leaves were rich in glucoraphanin, while the bulb held more glucoerucin
Lab analysis of nine kohlrabi tissues. A larger share of isothiocyanates, the more active breakdown products, formed in the leaf stalk, bulb peel, stem and root. No one ate anything in this study.
The skin of kohlrabi held much more carotenoid than the flesh, and purple kohlrabi had more phenylpropanoids
Lab profiling of the skin and flesh of pale green and purple kohlrabi found 8 glucosinolates, 12 anthocyanins, 2 carotenoids and 7 phenylpropanoids. Glucoerucin was 4-fold higher in the flesh of purple kohlrabi than in its skin. It describes what is in the vegetable, not effects in people.
Who should be careful with kohlrabi
Most people can eat kohlrabi freely. Take a little care if one of these applies:
- Warfarin. The USDA lists only 0.1 µg of vitamin K per 100 g of raw kohlrabi bulb, so the bulb is a small concern, but that figure does not cover the leaves. If you take warfarin, the NHS advises keeping your intake of green vegetables steady rather than avoiding them.
- Thyroid disease. Cruciferous vegetables have a goitrogen reputation, but a 2022 review found that avoiding them has little proven benefit in thyroid disorders. The concern is small, and kohlrabi sprouts did not change thyroid hormones in rats.
- Allergy to cabbage-family plants. A review of meta-analyses advises caution for people with an allergy or hypersensitivity to the Brassica genus.
How to choose, store and eat kohlrabi
- Raw: peel the fibrous outer layers, then slice or grate the crisp, mildly sweet flesh. A cup (135 g) holds 83.7 mg of vitamin C.
- Lightly cooked: in lab tests, brief heating raised isothiocyanate formation in kohlrabi, while boiling leached glucosinolates into the cooking water.
- Leaves: they are edible and can be cooked like collards or kale, though they take longer. Lab work found them rich in glucoraphanin.
Choose small to medium bulbs, just under 3 inches across, which are more tender, with no cracks or brown spots, and bright green, firm leaves if they are attached. Cut off the leaves and keep the bulb in a perforated bag in the fridge for about two weeks, and use the leaves within three days.
Sources
- Kohlrabi, raw (FDC ID 168424). USDA FoodData Central.
- Anticoagulant medicines: considerations. NHS.
- Larsen D, Singh S, Brito M. Thyroid, diet, and alternative approaches. J Clin Endocrinol Metab. 2022.
- Li N, Wu X, Zhuang W, et al. Cruciferous vegetable and isothiocyanate intake and multiple health outcomes. Food Chem. 2022.
- Paśko P, Okoń K, Prochownik E, et al. The impact of kohlrabi sprouts on various thyroid parameters in iodine deficiency- and sulfadimethoxine-induced hypothyroid rats. Nutrients. 2022.
- Hanschen FS, Kühn C, Nickel M, Rohn S, Dekker M. Leaching and degradation kinetics of glucosinolates during boiling of Brassica oleracea vegetables and the formation of their breakdown products. Food Chem. 2018.
- Mbudu KG, Witzel K, Börnke F, Hanschen FS. Glucosinolate profile and specifier protein activity determine the glucosinolate hydrolysis product formation in kohlrabi in a tissue-specific way. Food Chem. 2025.
- Kohlrabi. University of Illinois Extension.
- Kohlrabi. Wikipedia.
- How to avoid FODMAP stacking. Monash FODMAP blog. 2019.
History of kohlrabi
Kohlrabi was made by people selecting wild cabbage. Genetic work on 224 plants points to Brassica cretica, a wild relative native to the Aegean, as the closest living cousin of the whole cabbage species, which suggests that farming began in the Eastern Mediterranean. Growers then picked the plants that swelled their stems, and the botanical group name, Gongylodes, comes from a Greek word meaning roundish.
The first written record in Europe is from the botanist Pietro Andrea Mattioli in 1554, who described it as a recent arrival in Italy. By the end of the 16th century it was grown in Austria, Germany, England, Italy and Spain, as well as parts of the eastern Mediterranean.
The name joins the German words Kohl, cabbage, and Rübe, turnip, because the swollen stem looks like a turnip. Varieties include White Vienna, Purple Vienna and Gigante, also called Superschmelz.
In Kashmir, kohlrabi is called Mŏnji and is one of the most commonly cooked vegetables. It is prepared with its leaves, served in a light soup and eaten with rice.
Sources
- Mabry ME, Turner-Hissong SD, Gallagher EY, et al. The evolutionary history of wild, domesticated, and feral Brassica oleracea (Brassicaceae). Mol Biol Evol. 2021.
- Kohlrabi. Wikipedia.
- Brassica oleracea. Wikipedia.
Frequently asked questions about kohlrabi
Is kohlrabi good for you?
For most people, yes. Raw kohlrabi has 27 calories, 3.6 g of fiber and 62 mg of vitamin C (69% of the daily value) per 100 g. No trial has tested kohlrabi on health outcomes in people, though Chinese adults who ate the most cruciferous vegetables had a 22% lower risk of dying. That is a link, not proof, and it covers the whole group.
Can you eat kohlrabi raw?
Yes. Peel the fibrous outer layers first, and the flesh is crisp and mildly sweet, a little like a broccoli stem. In lab tests, brief heating raised isothiocyanate formation in kohlrabi while boiling leached glucosinolates into the water, so neither raw nor cooked is proven better. The skin held more carotenoids than the flesh in one analysis, but it is tougher to eat.
Can you eat kohlrabi leaves?
Yes, the leaves are edible. Cook them like collards or kale, though they take longer. In a lab analysis they were rich in glucoraphanin, and they keep best wrapped in a damp paper towel and used within three days.
Is kohlrabi a root vegetable or a turnip?
Neither. The swollen part is the stem, not a root, and kohlrabi is a cultivar of wild cabbage, Brassica oleracea, the same species as broccoli and kale. The name only says it looks like a turnip.
Is kohlrabi keto-friendly?
It fits a low-carb plan in normal portions. Raw kohlrabi has 2.6 g of net carbs per 100 g, and a cup (135 g) has 3.5 g of net carbs, 8.4 g of total carbs and 4.9 g of fiber.
Is kohlrabi good for diabetes?
It can fit, but no study tested it in people with diabetes. Net carbs are low at 2.6 g per 100 g. A phenolic-rich extract cut fasting blood glucose by 64% in diabetic rats, which says little about a plate of kohlrabi. Cohorts disagree on cruciferous vegetables, with a 16% lower diabetes risk in pooled studies and a 16% higher risk in US cohorts, so check portions and choices with your care team.
Is kohlrabi good for kidney patients?
It depends on the advice you were given. Raw kohlrabi has 350 mg of potassium per 100 g and 473 mg in a cup (135 g), about 10% of the daily value, and no study here tested people with kidney disease. If you were told to limit potassium, ask your dietitian how much kohlrabi fits.
Is kohlrabi good for IBS?
Probably, in normal servings, but no trial here measured symptoms. A 2019 Monash University FODMAP blog gives kohlrabi an upper green-light limit of 600 g, far more than people eat. Tolerance varies, so start with a small portion.