Mustard: the powder that works on the food beside it

The best measured thing mustard does happens to the vegetable next to it. In a randomised crossover in 12 healthy adults, one gram of powdered brown mustard stirred into 200 g of cooked broccoli raised the sulforaphane metabolite in 24 hour urine from 9.8 to 44.7 micromoles per gram of creatinine, over four times as much. The mustard carries an enzyme that survives the meal and works in the gut, which is what that trial set out to test. Twelve people, one meal and a urine marker is the whole of it, so nothing there says a person got healthier. Five grams of yellow mustard bran stirred into a potato and leek soup lowered blood glucose at 15, 30 and 90 minutes in 10 healthy men of about 21 years. Bran is a milling fraction of the seed rather than the jar in your fridge, and the trial followed one soup for two hours. Mustard did not measurably speed up metabolism in the one trial that tested it. With 21 g of it in a brunch meal, heat production in 22 young men ran 14 percent above the no-spice meal and did not reach significance, 59 against 52 kJ/h at P = 0.08. Appetite and how much those men ate later did not move at all.

The numbers, per 100 g

What your body absorbs

• One gram of powdered brown mustard added to 200 g of cooked broccoli raised the sulforaphane metabolite in urine from 9.8 to 44.7 micromoles per gram of creatinine in 12 healthy adults. — 12 healthy adults, randomised crossover, 200 g cooked broccoli with and without 1 g powdered brown mustard, all urine collected over the following 24 h (n = 12) Evidence B source
  Urinary sulforaphane N-acetyl-l-cysteine 9.8 (SD 5.1) vs 44.7 (SD 33.9) micromol per gram creatinine, over four times greater

What cooking and storage change

• Heavy use of mustard oil for cooking went with higher odds of gallbladder cancer in India, 1.33 in the high-risk region and 3.01 in the low-risk one, across 1170 cases and 2525 controls. — 1170 histologically confirmed gallbladder cancer cases and 2525 group-matched visitor controls at the largest cancer hospital in India, oil consumption estimated per person from monthly family purchases (n = 3695) Evidence C source
  Adjusted odds ratio 1.33 (95% CI 0.99 to 1.78) in the high-risk region and 3.01 (1.66 to 5.45) in the low-risk region; deep frying fresh fish in mustard oil OR 1.57 (0.99 to 2.47), p = 0.052

What it does to your health

• Five grams of yellow mustard bran stirred into a potato and leek soup lowered blood glucose at 15, 30 and 90 minutes in 10 healthy young men. — 10 healthy non-smoking moderately active males, mean age 21.1 years, mean BMI 23.2, randomised repeated-measures design, capillary glucose at 0, 15, 30, 45, 60, 90 and 120 min (n = 10) Evidence B source
  Blood glucose lower at 15 min (p < 0.0001), 30 min (p < 0.0001) and 90 min (p = 0.0059) with 5 g mustard bran
• Gum carrying 0.01% allyl isothiocyanate from mustard seed extract together with zinc lactate cut mouth-air sulfur compounds by 89% right after chewing and by 24% three hours later in 15 volunteers. — 15 healthy volunteers aged 20 to 50, single-blind crossover, experimental or placebo gum chewed for 12 minutes, mouth air by gas chromatograph at baseline and at 60, 120 and 180 minutes (n = 15) Evidence B source
  Total volatile sulfur compounds reduced by 89% immediately, 55.5% at 1 h, 48% at 2 h and 24% at 3 h
• Among 10111 rural Chinese adults aged 35 to 75, where 34.32% had hypertension, eating pickled potherb mustard sat in the same list of habits as a high-salt diet. — 10111 adults aged 35 to 75 resident in Huai'an District, Jiangsu Province for at least three years, cross-sectional data collected September 2012 to December 2017 (n = 10111) Evidence C source
  Hypertension prevalence 34.32%; pickled potherb mustard listed among factors associated with increased risk alongside fast eating speed, high-salt diet, high BMI and preference for fatty meats

Safety, limits and interactions

• 7 of 30 people who tested positive to mustard on a skin prick reacted to a blinded food challenge, and neither the prick test nor the IgE level predicted which ones, in either direction. — 30 subjects aged 3 to 20 with positive prick tests to ground mustard seeds, mustard flour and mustard seasoning; double-blind or single-blind placebo-controlled food challenges with up to 1340 mg of metabisulfite-free seasoning (n = 30) Evidence C source
  7 of 30 challenges positive, 23.3% of sensitised subjects; mean specific IgE 12.3 vs 7.6 KU/l in allergic vs non-allergic, P > 0.25

What people believe that the data does not support

• A 21 g dose of mustard in a meal failed to raise heat production significantly in 22 young men, and it changed neither their appetite nor how much they ate afterwards. — 22 young normal-weight males, mean age 24.9 years, BMI 21.8, five-way placebo-controlled single-blind crossover brunch meal with pepper 1.3 g, ginger 20 g, horseradish 8.3 g, mustard 21 g or no spice (n = 22) Evidence B source
  Diet-induced thermogenesis 59 (SE 3) vs 52 (SE 2) kJ/h with mustard against placebo, a 14% difference at P=0.08; appetite P>0.85, ad libitum energy intake P=0.63, energy balance P=0.67
• Mustard hides in condiments, sauces and processed foods, and United States labelling law does not require it to be declared as a major allergen. — United States food labelling under the Food Allergen Labeling and Consumer Protection Act, as described in a 2026 clinical case report Evidence D source
  No mandatory major-allergen disclosure for mustard in the United States, while European paediatric populations have long recognised it
• The oldest thing people say about mustard, that it wakes up the appetite and helps digestion, was put to the European regulator as a health claim and refused. — EU Register on nutrition and health claims, snapshot of 2026-09-21: 2330 claims, 262 authorised, 2067 non-authorised; 2 claims name white mustard and none is authorised (n = 2 claims naming mustard, 0 authorised) Evidence E source
  Claim POL-HC-7938 refused; sibling claim POL-HC-7939 refused

Who this works differently for

• A 23-month-old boy went into anaphylaxis within minutes of an isolated mustard exposure and needed intramuscular epinephrine. — one 23-month-old male with a history of IgE-mediated egg allergy, United States, 2026 (n = 1) Evidence D source
  Diffuse urticaria, lip swelling, circumoral discoloration and cough within minutes; skin prick 15 mm wheal with 25 mm flare; resolved after intramuscular epinephrine
• EFSA set a tolerable daily intake for erucic acid of 7 mg per kilogram of body weight, and named pastries, cakes and biscuits rather than mustard as the main source for young children. — EU population, with toddlers aged 1 to 2 and children aged 3 to 10 singled out as the highly exposed groups Evidence E source
  Tolerable daily intake 7 mg/kg body weight per day

What is still unknown

• Across the six common edible seeds including mustard, the published allergy literature is small and made mostly of single case reports rather than large series. — English literature from January 1930 to March 2016 on hypersensitivity to sesame, sunflower, poppy, pumpkin, flaxseed and mustard seed Evidence C source
  Sesame prevalence estimated at 0.1 to 0.2%; no comparable estimate exists for mustard; no well-designed immunotherapy study was found for any seed

The bottom line

Mustard is a real allergen and a poorly measured one. Of 30 people aged 3 to 20 with a positive skin prick to mustard, 7 reacted when the food was given blind, and neither the prick test nor the IgE level marked out which 7. Not predictive cuts both ways: neither test could say in advance who would react, and neither could say who would not. Those 30 were referred because they were already sensitised, so the 23.3 percent is a share among sensitised people rather than among everyone. Reactions can be fast and severe. A 23-month-old boy with a known egg allergy developed hives, lip swelling and cough within minutes of an isolated mustard exposure and needed intramuscular epinephrine. That is one published case, so it fixes no rate. No prevalence figure exists. A review of English language reports from 1930 to 2016 on six edible seeds found the mustard material is mostly single case reports, with no prevalence estimate for mustard and no well designed immunotherapy study for any of the seeds. Labelling matters here. The authors of that 2026 case report note that United States law does not require mustard to be declared a major allergen, while it hides in condiments, sauces and processed foods, and that European labels do carry it. Two things sold under the word mustard are a different product from the condiment. Heavy use of mustard oil as a frying medium went with gallbladder cancer in an Indian hospital case-control study of 1170 cases and 2525 controls. The adjusted odds ratios were 1.33 (95 percent CI 0.99 to 1.78) in the high-risk region and 3.01 (1.66 to 5.45) in the low-risk one. Exposure came from monthly family oil purchases, these are odds and not risks, and the first interval crosses 1. Pickled potherb mustard, a salted preserved vegetable, turned up among the habits tied to hypertension in 10111 rural Chinese adults aged 35 to 75, where 34.32 percent had it. It sat in the same list as a high salt diet, the survey was cross-sectional, and no separate effect size for the pickle is reported. Erucic acid, the fatty acid that mustard and rapeseed oils carry, has an EFSA tolerable daily intake of 7 mg per kilogram of body weight a day. The agency names pastries, cakes and biscuits as the main dietary source for children aged 1 to 10, ahead of anything made of mustard. The old line about mustard waking the appetite and helping digestion was filed with the European regulator twice and refused both times, which means the evidence did not meet the bar at assessment rather than that the effect was ruled out. One trial used mustard as a breath treatment. A gum with 0.01 percent allyl isothiocyanate from mustard seed extract cut mouth air sulfur compounds by 89 percent straight after 12 minutes of chewing and by 24 percent three hours later in 15 volunteers. That gum also carried zinc lactate, so the mustard compound cannot be credited on its own.

Sources

1. mstd-r4-01 · randomised controlled crossover trial
   When study subjects ingested cooked broccoli alone, mean urinary SF-NAC excreted was 9.8 ± 5.1 μmol per g creatinine, and when cooked broccoli was consumed with mustard powder, this increased significantly to 44.7 ± 33.9 μmol SF-NAC per gram creatinine.
   Mol Nutr Food Res, 2018 · checked 2026-09-24
2. mstd-r4-09 · case-control study
   High consumption of mustard oil was associated with GBC risk in both high- and low-risk regions (OR = 1.33, 95% CI = 0.99-1.78; OR = 3.01, 95% CI = 1.66-5.45), respectively.
   Int J Cancer, 2020 · checked 2026-09-24
3. mstd-r4-02 · randomised controlled trial
   Mean blood glucose values at 15, 30 and 90 min (p < 0.0001, p < 0.0001 and p = 0.0059, respectively) were all significantly lower with the addition of 5 g of yellow mustard bran.
   Int J Food Sci Nutr, 2013 · checked 2026-09-24
4. mstd-r4-04 · randomised controlled trial
   Chewing gum containing 0.1% zinc lactate and 0.01% of allyl isothiocyanate eliminated 89%, 55.5%, 48% and 24% of the total VSC concentration immediately after chewing and at 1, 2, and 3 hours after chewing, respectively.
   Am J Dent, 2013 · checked 2026-09-24
5. mstd-r4-12 · cross-sectional study
   Factors associated with an increased risk of hypertension included: fast eating speed, a high-salt diet (both currently and ten years ago), a high-spicy diet ten years ago, high BMI, poor educational attainment, preference for fatty meats, hot diet, green tea drinking, intake of pickled potherb mustard and corn flour, family smoking and alcohol consumption.
   Nutr Metab Cardiovasc Dis, 2024 · checked 2026-09-24
6. mstd-r4-05 · controlled clinical trial, food challenge
   About 23.3% of the sensitized subjects were allergic to a routine dose of mustard. Positive prick tests and the presence of specific IgE were not predictive.
   Allergy, 2003 · checked 2026-09-24
7. mstd-r4-03 · randomised controlled trial
   No significant treatment effects were observed on DIT, but mustard produced DIT, which tended to be larger than that of placebo (14 %, 59 (SE 3) v. 52 (SE 2) kJ/h, respectively, P=0·08).
   Br J Nutr, 2013 · checked 2026-09-24
8. mstd-r4-07 · case report
   Mustard is frequently present as a hidden ingredient in condiments, sauces, and processed foods and is not currently required to be disclosed as a major allergen under the United States Food Allergen Labeling and Consumer Protection Act (FALCPA).
   Cureus, 2026 · checked 2026-09-24
9. mstd-r4-11 · regulatory decision
   POL-HC-7938 Sinapis alba (Common Name : White mustard) Contributes to appetite / helps to support the digestion / helps to support the digestive juice flow / contributes to the gastro-intestinal movement. Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-7938, snapshot 2026-09-21 · checked 2026-09-24
10. mstd-r4-06 · case report
    We report a case of mustard-induced anaphylaxis in a 23-month-old male baby with a history of IgE-mediated egg allergy who developed diffuse urticaria, lip swelling, circumoral discoloration, and cough within minutes of isolated mustard exposure.
    Cureus, 2026 · checked 2026-09-24
11. mstd-r4-10 · agency risk assessment
    Based on this information, experts on EFSA's Panel on Contaminants in the Food Chain (CONTAM Panel) established a tolerable daily intake of 7 milligrams per kilogram of body weight (mg/kg bw) per day. ... For most consumers, especially for toddlers (1-2 years old) and other children (3-10), the main contributors to erucic acid exposure in the diet are pastries, cakes and biscuits.
    EFSA, Erucic acid a possible health risk for highly exposed children · checked 2026-09-24
12. mstd-r4-08 · systematic review
    Considering the worldwide consumption of those seeds, the number of published articles on the subject was relatively small and was mainly as case reports rather than large series.
    Allergy, 2016 · checked 2026-09-24