Daikon benefits: 18 kcal per 100 g — among the lowest of any vegetable

Key benefits

1. 01Moderate evidence

   Cruciferous vegetables tracked with lower cardiovascular disease, mortality and cancer — observational

   2017, International Journal of Epidemiology. A dose-response meta-analysis pooling 95 prospective studies across 142 publications.

   The overall result, for every additional 200 g a day of fruit and vegetables:

   • Coronary heart disease 0.92
   • Stroke 0.84
   • Cardiovascular disease 0.92
   • All-cause mortality 0.90

   In the analysis by type, cruciferous vegetables showed inverse associations with cardiovascular disease and total mortality, and cruciferous and yellow-green vegetables with total cancer risk. Daikon is cruciferous.

   Risk reduction was observed up to 800 g a day (600 g for cancer).

   Three things to be clear about.

   First, it is observational. People who eat more vegetables tend to smoke less and exercise more, and statistical adjustment cannot remove that entirely.

   Second, it does not single out daikon. What was examined is the cruciferous category.

   Third, how daikon is eaten in Korea may differ from the premise of that analysis. Vegetable intake in those studies generally means fresh vegetables. Pickled daikon and radish kimchi are salted preparations, and the sodium comes with them. Counting fresh radish as a vegetable is not the same as counting pickled radish.

   A note on glucosinolates. Radish's pungency comes from isothiocyanates formed when those compounds break down. There is much research on their inducing detoxification enzymes, but there is still no randomised evidence that this changes outcomes such as cancer or death in people.

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2. 02Nutrition data

   22 mg of vitamin C in 18 kcal — and each part tastes different

   Per 100 g of raw daikon:

   • 18 kcal, protein 0.6 g, fat 0.1 g
   • Of 4.1 g of carbohydrate, 1.6 g is fibre, sugar 2.5 g
   • Vitamin C 22.0 mg — 24% of the requirement
   • Potassium 227 mg, folate 28 µg
   • Calcium 27 mg, magnesium 16 mg, copper 0.115 mg
   • Sodium 21 mg

   The 18 kcal defines this vegetable. It is over 94% water. Adding it generously to a soup barely moves the calories.

   The 22 mg of vitamin C is heat-sensitive. Long simmering in soup loses much of it. More survives in uncooked forms — fresh salads and kimchi.

   Different parts taste different, and this is a distinction cooks actually use.

   • The top (near the leaves) — sweetest. Suits fresh salads.
   • The middle — balanced. For soups and braises.
   • The tail — the most pungent. The pungent compounds concentrate at the root tip.

   The pungency is isothiocyanate, formed when grating or chewing breaks the cells and the glucosinolates meet their enzyme. Grated radish grows sharper for a while and then fades — the compound is volatile.

   Winter daikon is sweeter. Cold converts starch to sugar. The season runs from late autumn through winter.

   The leaves count separately. They hold far more calcium, iron and beta-carotene than the root, which is why they are dried and used as siraegi.

3. 03Not established

   The "aids digestion" claim — the enzyme is real, the evidence is another matter

   This entry sorts through a claim that is not established.

   "Eat radish with rice cake and you will not get indigestion" is a long-standing saying. The reason usually given is that radish contains amylase (diastase).

   That fact is correct. Radish and many other vegetables contain starch-splitting enzymes.

   Whether that improves human digestion is a separate question.

   First, an enzyme is a protein. In the stomach, acid (pH 1.5–3.5) and pepsin break it down like any other protein. The same structure as bromelain on the pineapple page.

   Second, the human pancreas already secretes plenty of amylase. There is no evidence a healthy person needs it from outside. Saliva contains amylase too.

   Third, heat inactivates the enzyme. None survives in radish soup or a braise. The claim can only apply to raw or grated radish.

   Fourth, this site did not identify randomised evidence in people. If there were a trial showing radish improved dyspepsia, this would be a different entry; there is not.

   So why does it feel that way? Several explanations are available — radish's water and fibre can affect fullness and bowel movement, and its freshness alongside rich food may reduce the subjective sense of heaviness. But these are different mechanisms from the "digestive enzyme" story.

   The honest conclusion: serving radish alongside your food is a good habit. There is simply no evidence that the reason is its digestive enzymes.

How to eat it well

What to watch out for