Brussels sprouts are buds. They grow in a spiral up a stalk that stands 60 to 120 cm tall, and the botanical group name, gemmifera, means “bud-bearing”. They are the same species as cabbage, broccoli, kale and cauliflower, Brassica oleracea, shaped by growers into a very different vegetable.
Gram for gram, they are rich in two vitamins. A 100 g serving has 177 µg of vitamin K, 148% of the daily value, and 85 mg of vitamin C, 94%. Only 8 of the 96 foods compared on this site have more vitamin K per 100 g.
Their bitterness has a known cause. In the 1990s a Dutch scientist traced it to two glucosinolates, sinigrin and progoitrin, and seed companies then bred milder varieties from old stock. In a lab comparison of four raw brassicas, Brussels sprouts still had the most glucosinolates and tasted the most bitter. Several of the human trials below fed 300 g of sprouts a day, about 3.4 cups, a large daily portion.
Health benefits of Brussels sprouts
The top findings from 29 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 →- ★★Higher activity of a drug-processing enzymeIn 23 dietary trials, diets rich in cruciferous vegetables, Brussels sprouts among them, raised activity of the drug-processing enzyme CYP1A2 by 20 to 40%. People on drugs cleared by these enzymes could see different drug levels if they regularly eat large or variable amounts.
- ★Lower DNA damage markers in tiny studiesMen who ate 300 g a day of cooked Brussels sprouts for 3 weeks had a 28% lower urine marker of DNA oxidation. In 8 people, 300 g a day lowered DNA damage from hydrogen peroxide in white blood cells by 39%.
- ★No change in a breast cancer risk markerIn 78 women, 8 weeks of sprouts, broccoli or sprout-and-kale capsules left a urine hormone ratio, a proposed breast cancer risk marker, unchanged.
- ★Less of a cancer-causing chemical in bloodEating 50 g a day of sprouts for 7 days cut blood levels of a trace dose of the carcinogen benzo[a]pyrene by 56 to 67%. That range also covers a diindolylmethane supplement, and the study was small.
- ★Sweet cream cheese made sprouts more popularIn 29 children aged 3 to 5, pairing Brussels sprouts with sweetened cream cheese raised liking and eating more than sprouts alone. It was a small study.
All 29 studies, strongest evidence first
Diets rich in cruciferous vegetables, Brussels sprouts among them, raised the activity of the drug-processing enzyme CYP1A2 by 20 to 40%
Systematic review with a meta-analysis of 23 dietary trials in people, using broccoli, Brussels sprouts, cabbage, cauliflower, radish and watercress. Activity of glutathione S-transferase alpha rose 15 to 35%. The authors say reports disagree and the clinical importance is unclear, but people on drugs cleared by these enzymes could see different drug levels if they regularly eat large or variable amounts.
Eight weeks of Brussels sprouts and broccoli, or Brussels sprout and kale capsules, did not change a urine hormone ratio that is a proposed marker of breast cancer risk
Randomized, placebo-controlled, partly blinded trial in 78 healthy premenopausal women aged 38 to 50. They took six capsules of dried Brussels sprouts and kale, ate 40 g a day of broccoli or Brussels sprouts on alternating days, or took a placebo. Neither the capsules nor the extra serving changed the ratio of 2-hydroxyestrone to 16-alpha-hydroxyestrone. The ratio did change over time, which the authors say matters for planning future trials.
300 g a day of cooked Brussels sprouts for 3 weeks lowered a urine marker of DNA oxidation by 28% in men
Controlled study in 10 healthy, non-smoking men. Five ate the sprouts in place of 300 g of another vegetable and five stayed on a diet free of cruciferous vegetables, and the marker, 8-oxodG, did not change in that control group. This measures a lab marker, not illness, and only 10 men took part.
Eating 300 g a day of Brussels sprouts lowered DNA damage from hydrogen peroxide by 39% in white blood cells
Controlled intervention trial in 8 people, with DNA damage measured in white blood cells by the comet assay. Damage caused by a test compound called PhIP fell 97%, but damage from a second test compound did not change. Serum vitamin C rose 37%. These are lab markers in a very small group.
Ten days on a diet with cabbage and Brussels sprouts lowered the blood exposure to acetaminophen by 16% after a standard dose
Ten healthy people ate a control diet, a diet containing cabbage and Brussels sprouts together, then the control diet again, for 10 days each. The sprout diet also raised the clearance of acetaminophen by 17% and lowered blood exposure to the sedative oxazepam by 17%. The acetaminophen change returned toward normal on the second control diet. Brussels sprouts were not tested alone.
A repeat trial with 300 g a day of Brussels sprouts found a lower DNA oxidation marker in four of five men and no effect in women
Crossover trial in 10 non-smokers, 5 men and 5 women, who ate 300 g a day of sprouts or of glucosinolate-free vegetables for a week each. In the fifth man the marker was high in the control week and much higher in the sprout week. The authors see the results as in line with studies linking brassica vegetables to lower cancer risk, but the trial was tiny.
300 g a day of cooked Brussels sprouts for 3 weeks raised blood levels of the enzyme GST-alpha by a factor of 1.4 in men
Controlled study in 10 healthy, non-smoking men after a 3-week run-in, with 5 eating sprouts in place of another vegetable and 5 as controls. GST-alpha belongs to a family of enzymes that help the body clear foreign compounds, and the authors suggest the blood level reflects higher levels in the liver and gut. It is an enzyme marker, not a health outcome.
300 g a day of cooked Brussels sprouts for a week raised GST-alpha by 30% and GST-pi by 15% in rectal tissue
Crossover trial in 10 healthy non-smokers who ate sprouts in place of 300 g of glucosinolate-free vegetables for 7 days. Total GST activity and glutathione content did not change. The authors suggest the higher enzyme levels may partly explain the link between cruciferous vegetables and a lower risk of colorectal cancer, which this trial did not test.
300 g a day of cooked Brussels sprouts for a week raised blood GST-alpha 1.5-fold in men but not in women
Crossover trial in 5 men and 5 women, all non-smokers. Blood GST-pi and urine GST levels did not change. The authors conclude that the rise in men most likely came from the liver and that men may respond more than women.
Pairing Brussels sprouts with sweetened cream cheese raised preschoolers’ liking and eating of them more than showing the sprouts alone
Study in 29 children aged 3 to 5. One group got sprouts with sweetened cream cheese and cauliflower with plain cream cheese, a second got the reverse, and a third got both vegetables on their own. Pairing helped for the bitter sprouts, while cauliflower was liked by all groups whether or not it came with cream cheese. It was a small study.
300 g a day of Brussels sprouts for 3 weeks did not raise HDL cholesterol in young men
Controlled dietary trial in healthy, non-smoking men aged 20 to 28, who ate sprouts in place of glucosinolate-free vegetables. HDL phospholipids and the HDL proteins apo A-I and apo A-II did not rise either. The idea tested was that plant compounds that switch on liver enzymes might raise HDL, as some drugs do.
Seven days of 50 g a day of Brussels sprouts, or of a diindolylmethane supplement, lowered blood levels of a trace dose of the carcinogen benzo[a]pyrene by 56 to 67%
Human study in which volunteers followed a diet restricted in cruciferous vegetables for 14 days, added the sprouts or supplement for 7 days, then took a tiny radiolabeled dose of benzo[a]pyrene. The range covers both treatments, which appeared to slow its absorption. The authors name the small number of subjects and large differences between people as limits.
People who ate the most Brussels sprouts had 34% lower odds of stomach cancer
Hospital-based case-control study of 292 stomach cancer patients and 1,168 cancer-free controls in Buffalo, New York (odds ratio 0.66, range 0.48 to 0.91). Highest against lowest intakes of raw cruciferous vegetables overall (0.53), raw broccoli (0.61) and raw cauliflower (0.51) also went with lower odds. Diet was recalled by questionnaire, so a link is not proof.
Eating more cruciferous vegetables, Brussels sprouts included, was not linked to the risk of bladder cancer
Cohort of 515,628 people in the NIH-AARP Diet and Health Study. Overall intake and each type on its own (broccoli, Brussels sprouts, cauliflower) showed no link for men or women, and smoking history did not change this. Diet came from food questionnaires.
Eating Brussels sprouts once a week or more went with a 16% higher risk of coronary heart disease than eating them less than once a month
Three US cohorts with 210,574 people and 8,010 cases over about 4.8 million person-years. Cabbage went with a 9% higher risk, and the top fifth for total glucosinolates with a weak 9% higher risk. The authors ask for replication, including biomarker studies, and a link is not proof of cause.
In a meta-analysis of fruit and vegetable types, Brussels sprouts were linked to a higher risk of high blood pressure, while broccoli was linked to a lower risk
Meta-analysis of 18 prospective studies with 451,291 people. Cruciferous vegetables overall and cantaloupe also showed positive links, based on only 2 to 5 studies each, while carrots and lettuce showed inverse ones. The authors call the results for single foods mixed and in need of more study.
In a review of 94 studies, only 29% of case-control studies linked Brussels sprouts to lower cancer risk, against 70% for cabbage
Overview of 7 cohort and 87 case-control studies of brassica vegetables and cancer. The authors conclude that a high intake of brassicas goes with lower cancer risk, most consistently for lung, stomach, colon and rectal cancer, but they note possible bias and that brassicas cannot yet be separated from vegetables in general. It dates from 1996.
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, not Brussels sprouts alone.
Adults who tasted a bitter test compound as strongest also rated Brussels sprouts, kale and asparagus as the most bitter and least sweet
Tasting study in 110 adults aged 18 to 60 (71 women, 39 men). The bitterness and sweetness they reported predicted how much they liked these vegetables and how many servings they ate. The test compound, PROP, is a marker of genetic differences in taste. The study did not test health effects.
Boiling Brussels sprouts and other brassicas lost glucosinolates into the cooking water, while steaming, microwaving and stir-frying did not
Lab analysis of broccoli, Brussels sprouts, cauliflower and green cabbage. About 90% of the glucosinolates lost in boiling were found in the cooking water. Storage for 7 days at room temperature or in a fridge lost 9 to 26%, and finely shredded vegetables lost up to 75% over 6 hours. The four vegetables are reported together.
Boiling Brussels sprouts in water lost the most nutrients to the cooking water, while steaming and sous vide kept more
Lab comparison of boiling, steaming and sous vide cooking. Boiling lowered dry matter by 11.8% and most minerals by 7.6 to 39.8%. Steaming and sous vide kept most minerals at the level of the raw sample. These are measurements of cooked sprouts, not a study in people.
Sous vide cooking of Brussels sprouts lost more glucosinolates than conventional cooking
Lab study of several heat treatments followed by a simulated digestion. Isothiocyanates and indoles did not differ significantly between methods. Three glucosinolates (glucoraphanin, glucoraphenin and gluconasturtiin) were completely broken down during the simulated digestion.
Air-frying at 160 °C for 10 minutes gave the highest antioxidant activity of four heat treatments across five brassicas, including Brussels sprouts
Lab test of freeze-drying, sautéing, steaming and air-frying on kale, broccoli sprouts, Brussels sprouts, red cabbage and green cabbage. Sautéing gave the lowest values and steaming beat freeze-drying. The abstract does not separate Brussels sprouts from the others, and test-tube antioxidant assays do not show effects in people.
Oven-dried Brussels sprouts kept their ability to switch on detoxification enzymes even though heat had removed most of their glucosinolates
Lab study in liver cells and in mice fed a diet with 20% oven-dried sprouts for 2 weeks. Glucosinolates were 0.85 µmol/g after oven-drying against 22.14 after freeze-drying, yet enzyme activity rose in the cells and in the livers and lungs of the mice. The authors suggest compounds formed by heating are responsible.
In a lab comparison of four raw brassicas, Brussels sprouts had the most glucosinolates and tasted the most bitter
Chemical and taste analysis of extracts of broccoli, cauliflower, Brussels sprouts and red cabbage. Sprouts held 186.3 µg of glucosinolates per gram of fresh weight, against 164.1 for broccoli. Glucosinolates alone did not explain the bitterness, so phenolics and other compounds probably contribute, and sugars offset it.
Rats fed 10 or 20% freeze-dried Brussels sprouts for 6 days raised the enzyme quinone reductase 1.5 to 2.5 times in the liver
Study in rats, 4 per group, not in people. Colon levels rose 3.1 to 3.6 times and pancreas levels 1.4 to 2.3 times. A urine compound formed from a sprout glucosinolate also appeared in one person who ate 500 g of sprouts, which the authors propose as a marker of intake.
In rats, cooked Brussels sprouts lowered a urine marker of DNA oxidation by 31%
Study in groups of 6 to 8 rats, not in people. An extract of cooked sprouts also cut the rise in DNA oxidation caused by a chemical in the liver and protected bone marrow completely. Other test foods and isolated glucosinolates had no significant effect on the urine marker.
Extracts of cooked Brussels sprouts reduced hydrogen peroxide DNA damage in human white blood cells by up to 38%, but extracts of raw sprouts did not
Cell study, not in people. The glucosinolate sinigrin alone cut DNA strand breaks by up to 54%, and the effect weakened at higher concentrations. Oxidized DNA bases were not reduced.
Brussels sprouts contain enough goitrin to potentially lower thyroid iodine uptake
Review of goitrin and thiocyanate, compounds that can reduce thyroid hormone production. Radioiodine uptake was blocked by 194 µmol of goitrin but not by 77 µmol. The authors say thiocyanate from these vegetables carries minimal risk. Two authors work for a produce company, D’Arrigo Bros.
Who should be careful with Brussels sprouts
Most people can eat Brussels sprouts freely. Take a little care if one of these applies:
- Warfarin. Brussels sprouts are rich in vitamin K (177 µg per 100 g), which can change how this blood thinner works. You do not need to avoid them; keep the amount steady from week to week and check with your clinic before big changes.
- Irritable bowel syndrome or a gassy gut. Monash University says Brussels sprouts may contain components other than FODMAPs that can still cause symptoms such as excess gas, and it uses 75 g as an example of an amount that counts as high in fructans. A small portion is the safer start.
- Thyroid problems or low iodine. Brussels sprouts contain goitrin, which in a review could lower thyroid iodine uptake at high doses. The Linus Pauling Institute says such goitrogens rarely matter unless eaten in large amounts or with iodine deficiency, so the concern is small for most people.
How to choose, store and eat Brussels sprouts
- Steamed or microwaved: in a lab test these methods, and stir-frying, did not significantly cut glucosinolates, while boiling did, and about 90% of what was lost ended up in the cooking water.
- Boiled: boiling lost the most to the water, with dry matter down 11.8% and most minerals down 7.6 to 39.8% in a second lab comparison, while steaming and sous vide kept more.
- Roasted or air-fried: dry heat has no cooking water to lose things to. Air-frying at 160 °C for 10 minutes gave the highest antioxidant activity across five brassicas, and Nebraska Extension suggests roasting at 400 °F for 30 to 45 minutes.
Pick firm, compact, bright green sprouts without damaged or discolored leaves, and keep them unwashed in a plastic bag in the fridge for up to a week. Finely shredded brassicas lost up to 75% of their glucosinolates over 6 hours in the lab, so shred them just before cooking or eating.
Sources
- Dietary advice for patients taking warfarin. Cambridge University Hospitals NHS Foundation Trust.
- Anticoagulant medicines: considerations. NHS.
- Monash FODMAP reintroduction update: new food testing. Monash FODMAP blog. 2025.
- Fructans and FODMAP reintroduction. Monash FODMAP blog. 2020.
- Iodine. Linus Pauling Institute Micronutrient Information Center, Oregon State University.
- Felker P, Bunch R, Leung AM. Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism. Nutr Rev. 2016.
- Song L, Thornalley PJ. Effect of storage, processing and cooking on glucosinolate content of Brassica vegetables. Food Chem Toxicol. 2007.
- Doniec J, Florkiewicz A, Duliński R, Filipiak-Florkiewicz A. Impact of hydrothermal treatments on nutritional value and mineral bioaccessibility of Brussels sprouts (Brassica oleracea var. gemmifera). Molecules. 2022.
- Nandasiri R, Semenko B, Wijekoon C, Suh M. Air-frying is a better thermal processing choice for improving antioxidant properties of Brassica vegetables. Antioxidants (Basel). 2023.
- Brussels sprouts. University of Nebraska–Lincoln Extension.
History of Brussels sprouts
Brussels sprouts start with a very old plant. Cabbage, broccoli, kale and Brussels sprouts all belong to one species, Brassica oleracea, and a 2021 genetic study points to the Aegean wild cabbage B. cretica as its closest living relative, which supports an origin of cultivation in the Eastern Mediterranean. The sprout form came later, in northern Europe.
Nobody agrees on exactly when. Food reference books place them near Brussels in the 13th century, give 1587 for the first written description, or say they were widely grown in Europe only from the 17th century. The Oxford Companion to Food says they became known in French and English gardens at the end of the 18th century, and food historians quoted by the Food Timeline treat claims that the Romans grew them as undocumented.
The English record is clearer. The Oxford English Dictionary gives 1796 for the first printed mention of Brussels sprouts, in Charles Marshall’s book on gardening, and the first cookery writer to mention them seems to be Eliza Acton, in 1845. She boiled them and poured melted butter over them, in what she called the Belgian mode.
In America, French settlers grew them in Louisiana, and Thomas Jefferson planted some in 1812. Commercial plantings began in the Louisiana delta in 1925 and moved to the California coast by 1939, where most US sprouts are still grown.
For decades they were scorned. A California grower told NPR that people of his generation hated them because their mothers boiled them into something even smellier, and that they really were very bitter. That changed in the 1990s, when the Dutch scientist Hans van Doorn identified the bitter compounds, sinigrin and progoitrin. Seed companies then searched their archives for old low-bitterness varieties and crossed them with modern high-yield ones, and restaurant chefs, mainly in the US, helped turn the milder sprouts into a trend.
In the UK they are still a Christmas vegetable. A 2010 trade magazine article reported that around 40% of the sprouts grown for the UK market are eaten in the weeks up to and including Christmas Day.
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.
- Brussels sprout. Wikipedia.
- Food Timeline: Brussels sprouts. Lynne Olver. Quotes Kiple KF, Ornelas KC, eds, The Cambridge World History of Food (2000); Davidson A, The Oxford Companion to Food (1999); Ayto J, An A to Z of Food and Drink (2002).
- From culinary dud to stud: how Dutch plant breeders built our Brussels sprouts boom. Charles D. NPR. 2019.
- Brussels: a bittersweet story. Chemistry & Industry, issue 24. Society of Chemical Industry. 2010.
- van Doorn HE, van Holst GJ, van der Kruk GC, Raaijmakers-Ruijs NC, Postma E. Quantitative determination of the glucosinolates sinigrin and progoitrin by specific antibody ELISA assays in Brussels sprouts. J Agric Food Chem. 1998.
- Zabaras D, Roohani M, Krishnamurthy R, Cochet M, Delahunty CM. Characterisation of taste-active extracts from raw Brassica oleracea vegetables. Food Funct. 2013.
Frequently asked questions about Brussels sprouts
Are Brussels sprouts good for you?
For most people, yes. Raw Brussels sprouts have 43 calories, 3.8 g of fiber, 177 µg of vitamin K and 85 mg of vitamin C per 100 g. In 10 men, 300 g a day for 3 weeks lowered a urine marker of DNA oxidation by 28%, but that is a lab marker, and cohorts disagree: 34% lower odds of stomach cancer in one study, a 16% higher heart disease risk in another. No Brussels sprouts finding here reaches strong evidence.
Why do Brussels sprouts make you gassy?
No trial here measured gas, but fiber is part of it: raw sprouts have 3.8 g per 100 g. Monash University says Brussels sprouts may also contain components other than FODMAPs that can cause excess gas, and it uses 75 g as an example of an amount that is high in fructans. If they bother you, try a smaller portion.
How many Brussels sprouts should you eat a day?
No study here sets an ideal amount. Trials fed 300 g a day for 1 to 3 weeks, 50 g a day for 7 days, and 40 g a day of broccoli or sprouts for 8 weeks. One cup (88 g) has 38 calories and 156 µg of vitamin K, so if you take warfarin, keep the amount steady and ask your clinic.
Are Brussels sprouts better raw or cooked?
Neither is clearly better, and no trial compared them in people. In the lab, steaming, microwaving and stir-frying kept glucosinolates, while boiling washed them into the water. In a cell study, extracts of cooked sprouts protected white blood cells from DNA damage by up to 38%, and extracts of raw sprouts did not.
Why are Brussels sprouts bitter?
Two glucosinolates, sinigrin and progoitrin, are the main bitter compounds, and breeders have since made milder varieties. A 2013 lab study found that glucosinolates alone did not explain the bitterness, so other compounds contribute. Genes matter too: in 110 adults, those who tasted a test compound as most bitter also rated sprouts, kale and asparagus as the most bitter.
Are Brussels sprouts high in protein?
Fairly, for a vegetable. Raw Brussels sprouts have 3.4 g of protein per 100 g, or 3 g in a cup (88 g). Protein supplies about 31% of their calories, so they add to a meal without being the main source.
Are Brussels sprouts good for weight loss?
No study here tested weight loss. Raw Brussels sprouts have 43 calories and 3.8 g of fiber per 100 g, or 38 calories in a cup (88 g), so they fill a plate cheaply. That is a swap effect for higher-calorie foods, not a proven effect of the sprouts themselves.
Are Brussels sprouts healthier than broccoli?
No trial compared them, and each has strengths. Per 100 g, sprouts have more vitamin K (177 against 102 µg) and fiber (3.8 against 2.4 g), while broccoli has 31 calories against 43 and slightly more vitamin C (91 against 85 mg). Both score high on our nutrient density measure (588 and 615), and in one meta-analysis broccoli was linked to lower blood pressure risk and sprouts to higher, based on few studies.