Benefits
A source of vitamin C and fiber
Per 100 g raw, cauliflower supplies about 48 mg of vitamin C, 2 g of dietary fiber and 57 micrograms of folate for 25 kcal, according to USDA data. Boiled, drained cauliflower is listed at about 44 mg of vitamin C per 100 g. These figures describe nutrient content, not a tested health effect.
Fewer carbohydrates and calories than cooked white rice
Per 100 g, raw cauliflower has about 5 g of carbohydrate, 2 g of fiber and 25 kcal, while cooked white rice has about 28 g of carbohydrate, 0.4 g of fiber and 130 kcal, according to USDA data. This is why riced cauliflower is used in place of rice. It is a nutrient comparison, not a tested health outcome.
Post-meal blood glucose when cooked cauliflower was eaten with rice
In a randomized crossover test of single meals in 16 healthy young women, rice eaten with 300 g of cooked cauliflower had a glycemic index of 73, significantly lower than rice alone. When the cauliflower was pureed first, the difference from rice disappeared, and pak choi and eggplant gave similar or lower values. This was one meal at a time, not long-term blood sugar control.
Blood pressure and glucose in a crucifer soup trial (25% cauliflower)
In a 2-week crossover trial of 18 older adults with mildly raised blood pressure, crucifer soups (40% broccoli, 25% cauliflower) lowered 24-hour systolic pressure by 2.5 mmHg and post-meal glucose slightly versus root and squash soups. Average glucose did not differ, and cauliflower was not tested alone.
Gut bacteria on a high-Brassica diet that included cauliflower
In a crossover trial of 10 healthy adults, 2 weeks of a high-Brassica diet (broccoli, broccoli soup and cauliflower) lowered the share of sulfate-reducing gut bacteria compared with a low-Brassica diet, while lactobacilli did not change. Cauliflower was one part of the diet, and gut symptoms were not an outcome.
Glucosinolates and isothiocyanates from cauliflower
In a survey of Brassica crops, cauliflower's main glucosinolates were sinigrin and glucobrassicin. After two volunteers ate broccoli and cauliflower, breakdown products of sulforaphane and allyl isothiocyanate appeared in their urine. In lab tests of Brassica vegetables including cauliflower, boiling, but not steaming or microwaving, leached them into the water.
Mechanism of action
Glucosinolates and isothiocyanates
Cauliflower contains glucosinolates, mainly sinigrin, which the plant enzyme myrosinase turns into allyl isothiocyanate; in lab tests, finely shredded Brassica vegetables lost glucosinolates partly as isothiocyanates. In a human study of cabbage, a variety of the same species, cooking lowered and delayed this, with colon bacteria apparently taking over. Sulforaphane forms from a different glucosinolate, glucoraphanin, covered on our sulforaphane page.
Glutathione conjugation and urinary excretion
Isothiocyanates are absorbed, joined to glutathione and excreted in urine as mercapturic acids. A method study measured sulforaphane and allyl isothiocyanate mercapturic acids in 24-hour urine from two volunteers after a broccoli and cauliflower meal.
Intact vegetable texture and starch digestion
In lab digestion tests, a meal of rice and cooked cauliflower released starch more slowly (80.6% of the rate for rice alone). Blending removed the effect on blood glucose in volunteers, so the authors pointed to the physical texture of the vegetable rather than a specific compound.
Induction of drug-metabolizing enzymes
A meta-analysis of diet trials with broccoli, Brussels sprouts, cabbage, cauliflower, radish and watercress found that crucifer-enriched diets raised CYP1A2 activity by 20 to 40% and glutathione S-transferase alpha by 15 to 35%. Cauliflower was not studied alone.
Clinical trials
Randomized crossover glycemic response study: 13 test sessions per person, comparing rice alone and glucose with rice eaten with 300 g of pak choi, cauliflower or eggplant (100 g first, 200 g with the rice), whole or homogenized, raw or cooked; plus in vitro starch digestion. (Zhu et al. 2018, Br J Nutr)
16 healthy young women (aged 18 to 24, BMI 20 to 24.9) in China.
Rice with whole cooked cauliflower had a glycemic index of 73, significantly lower than rice alone; homogenized versions did not differ from rice. In vitro starch hydrolysis was 80.6% of rice. Eggplant had the largest effect. Single meals in young women only. No specific grant funding; no conflicts declared.
Randomized crossover trial of a high-Brassica diet (six 84 g portions each of broccoli and cauliflower plus six 300 g broccoli and sweet potato soups over 2 weeks) versus a low-Brassica diet (one portion each), with 2-week Brassica-free washouts. (Kellingray et al. 2017, Mol Nutr Food Res)
10 healthy adults in the UK.
Lactobacilli did not change (p = 0.80). The high-Brassica diet lowered the relative abundance of sulfate-reducing bacteria (p = 0.02) and several other groups. No adverse effects were reported. Broccoli was the lead vegetable. Funded by public research councils; no conflicts declared.
Randomized controlled crossover trial, participants not told 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 0.2 mmol/L more (P = 0.047). Nighttime aortic diastolic pressure was 2.9 mmHg higher with the crucifer soup (P = 0.014). No adverse events. Funded by university and state health department grants. A small, short trial of a blend, not cauliflower alone.
Prespecified secondary analysis of the VESSEL crossover trial, with flash glucose monitoring every 15 minutes during both 2-week soup periods. (Connolly et al. 2025, Diabetes Obes Metab)
18 adults without diabetes (89% women, median age 68) with raised blood pressure.
Glucose variability was 2.0% lower and the 2-hour post-meal glucose response 0.14 mmol/L lower with the crucifer soups, driven by dinner. Mean glucose did not differ (p = 0.41). The authors called the clinical impact uncertain. Cauliflower was one of four vegetables.