Radish: a vegetable almost nobody has tested as a vegetable

The one randomised trial on this page never fed anybody a radish. It gave 21 people with metabolic syndrome a concentrated powder of Sakurajima radish, a named Japanese cultivar, for 14 days. Their systolic blood pressure came out 9.67 mmHg higher than on their usual diet, a marker of oxidative stress in their urine went up as well, and the blood vessel function the trial had set out to measure did not improve, on a comparison the authors themselves say a carryover effect limits. A powder of one cultivar is a different thing from the vegetable you slice into a salad, the trial was small and open-label, and the direction of that result is the unwelcome one. Read it as a result about that powder. It is not a finding that radish raises your blood pressure. The health claims sellers like to make for radish have been through a regulator and did not pass. One European register entry covers black radish and the wording that it is usually recognised for helping digestion and transit. Another bundles eight digestive and liver wordings for the common radish. Neither has been authorised. A rejected claim means the assessors were not convinced, and it does not prove the effect is absent. What is left is a cheap, crunchy vegetable with no tested benefit to its name, because nobody has put ordinary raw radish against a health outcome at all. That describes most vegetables and is not a mark against it.

The numbers, per 100 g

What your body absorbs

• Eating oriental radish together with a beta-carotene supplement cut the serum response to two-thirds of what the supplement gave alone, in 10 healthy men. — 10 healthy men, single ingestion of each test source, serum followed to 32 hours (n = 10) Evidence B source
  Relative bioavailability 65 percent for beadlets with radish against 100 percent for beadlets alone

What it does to your health

• Fourteen days of concentrated Sakurajima radish powder, not radish as eaten, raised systolic blood pressure by 9.67 mmHg and a marker of oxidative stress in 21 patients with metabolic syndrome, and the primary outcome the trial was built on, endothelial function, did not improve. — 21 patients with metabolic syndrome, three 14 day periods (Sakurajima radish powder, Aokubi radish powder, usual diet) with 14 day washouts (n = 21) Evidence B source
  Systolic pressure +9.67 mmHg versus usual diet (p = 0.03) and +8.86 mmHg versus Aokubi radish (p = 0.04), urinary 8-OHdG/creatinine raised (p = 0.02), flow-mediated dilation unchanged (p = 0.58). The authors report a negative carryover effect that limits that primary outcome. A concentrated powder of one Japanese cultivar is a different thing from radish in food, so this is not a finding that radish raises blood pressure

Safety, limits and interactions

• Pooling 23 human dietary intervention trials, diets enriched with cruciferous vegetables including radish raised CYP1A2 activity by 20 to 40 percent and glutathione S-transferase alpha by 15 to 35 percent. — 23 dietary intervention trials in humans with drug metabolism endpoints, found in Embase, Medline and CENTRAL (n = 23 trials) Evidence A source
  CYP1A2 activity up 20 to 40 percent, GST-alpha up 15 to 35 percent
• Raw Japanese radish caused pollen food allergy syndrome in a 31 year old man with no allergy history, confirmed by skin-prick test. — one 31 year old man presenting with stomatitis and pharyngeal pain after frequently eating raw Japanese radish (n = 1) Evidence D source
  Oropharyngeal symptoms on ingestion, diagnosis confirmed by skin-prick test

What people believe that the data does not support

• The European register entry for black radish, the wording that it is usually recognised for helping digestion and transit, is recorded as non-authorised. — regulatory register entry, no study population Evidence E source
  Claim not authorised for use on labels in the European Union
• The eight digestive and liver wordings submitted for Raphanus sativus, the common radish, were all rejected in one European register entry. — regulatory register entry, no study population Evidence E source
  Claim not authorised for use on labels in the European Union

Who this works differently for

• Adding radish to the usual diet for a week raised urinary calcium oxalate crystal counts in 36 people, 21 of them stone formers. — 36 subjects in Nepal, 21 with renal stones and 15 without, morning urine sampled daily for 14 days across a self-selected week and a radish week (n = 36) Evidence C source
  Higher calcium oxalate crystal counts on the radish diet in both sexes, with no significant difference between men and women

The bottom line

Two useful things come out of the rest. Radish can get in the way of what you eat with it. When 10 healthy men took a beta-carotene supplement together with oriental radish, the amount reaching the blood fell to two-thirds of what the supplement gave on its own. That was one meal in ten men, and nobody has worked out why it happens. The second thing belongs to the whole cruciferous family that radish sits in. Pooling 23 human feeding trials, diets enriched with cruciferous vegetables raised CYP1A2 activity by 20 to 40 percent and glutathione S-transferase alpha by 15 to 35 percent, which are two of the systems the liver uses to clear drugs. Raising them means the liver can clear a drug faster, so the amount of that drug left in you goes down rather than up. Radish was one of six vegetables in those diets, so the number belongs to the family, and the authors say what it means in the clinic is still unclear. It is not a reason to eat fewer vegetables. Who should be careful. Three groups have a reason to read this page differently from everyone else. If you form kidney stones: adding radish to the usual diet for a week raised calcium oxalate crystal counts in the urine of 36 people in Nepal, 21 of whom were stone formers. Crystals in urine are a marker and not a stone, the study was small, it was not randomised, and the abstract reports no effect size. If you take a medicine whose dose has to be exact: the cruciferous result above is worth one question to your pharmacist, because a liver clearing a drug faster can leave less of it in you than the dose assumes. If raw radish makes your mouth or throat itch: a 31 year old man with no allergy history developed mouth and throat symptoms after frequently eating raw Japanese radish, confirmed by a skin-prick test. One case tells you the thing exists and nothing about how often it happens. In all three, take it to the person treating you rather than acting on it alone. The honest part of this page is how much of it is missing. No trial has put ordinary raw radish against any hard health outcome. Our sources say nothing about what boiling, drying or pickling does to it, though the food data below covers all four forms. Nothing in them crosses radish with pregnancy at all. Those are holes in the evidence, and a hole is not a reassurance.

Sources

1. radi-r5-02 · controlled crossover trial
   Concurrent ingestion of oriental radish reduced the bioavailability of beadlets to two-thirds of its original value, which partially accounted for the difference between the bioavailability of beadlets and natural foods.
   J Nutr, 2000 · checked 2026-09-23
2. radi-r5-01 · RCT crossover
   Despite successfully stimulating NO production (elevated urinary NOx, p = 0.03), the intervention paradoxically increased oxidative stress (elevated 8-OHdG/creatinine, p = 0.02) and significantly elevated systolic BP compared with the usual diet (+9.67 mmHg, p = 0.03) and Aokubi radish (+8.86 mmHg, p = 0.04).
   Nutrients, 2026 · checked 2026-09-23
3. radi-r5-03 · meta-analysis of intervention trials
   The meta-analyses performed demonstrated a significant effect on CYP1A2 and glutathione S-transferase-alpha (GST-α), with consumption of Cruciferae increasing the activities of these enzymes by 20-40% and 15-35%, respectively.
   Clin Pharmacol Ther, 2020 · checked 2026-09-23
4. radi-r5-05 · case report
   He reported frequently consuming raw Japanese radish (Raphans sativus L.) which gave rise to his symptoms. Japanese radish was suspected as the allergen. The skin-prick test confirmed the diagnosis of PFAS.
   Indian J Dermatol, 2023 · checked 2026-09-23
5. radi-r5-06 · regulatory register
   POL-HC-7866 Radis noir: Raphanus niger (Black radish) Usually recognized for helping digestion. Usually recognized for helping transit Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-7866, snapshot 2026-09-21 · checked 2026-09-23
6. radi-r5-07 · regulatory register
   POL-HC-7868 Raphanus sativus - common name : radish, black radish, Japanese radish, Daikon Used to facilitate the digestion "Helps to support normal liver function" "Contributes to the stimulation of the production of the digestive body fluids" "Supports the liver and biliary function" "Contributes to the digestive comfort" "Helps to facilitate fat digestion" "Contributes to better fat digestion" "Helps to support the digestion" "Contributes to support the digestion". Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-7868, snapshot 2026-09-21 · checked 2026-09-23
7. radi-r5-04 · controlled clinical trial
   The study reveals that radish containing diet caused increased excretion of calcium oxalate compared to the self-selected diet and the crystals count in the urine were significantly higher in both genders.
   Nepal Med Coll J, 2004 · checked 2026-09-23