Radishes are the most underrated vegetable in the shop. They cost very little, grow in three weeks in a pot on the windowsill, and bring a peppery crunch that wakes up a salad, a sandwich or a plate of buttered bread.

They also carry a surprising amount of folklore. The original version of this article credited radishes with clearing sinuses, cleansing the kidneys, balancing thyroid hormones and producing permanent weight loss. Here's what holds up, and what's simply a good excuse to eat a crunchy vegetable.

Directions for use

  • A cup of sliced radishes has about 19 calories, 2 grams of fibre and around a fifth of your daily vitamin C.
  • Radishes are cruciferous vegetables, cousins of cabbage and broccoli, and contain the same kind of sulphur compounds (glucosinolates) that give them their bite.
  • They are not a thyroid treatment or a weight-loss food. They are a very low-calorie, filling crunch that makes healthy eating more enjoyable.
  • Eat the leaves too: they're edible and nutritious.

What radishes offer

Very few calories, lots of crunch. At under 20 calories a cup, radishes are one of the most filling snacks for the fewest calories. That's the honest link to weight: replacing crisps with radishes helps, but no food causes weight loss by itself.

Vitamin C. A cup of sliced radishes gives about 17 mg, around a fifth of what women need. Vitamin C is essential for making collagen, the protein that keeps skin firm, which is one reason radishes earned a reputation as a "beauty" food.

Glucosinolates. Like other cruciferous vegetables, radishes contain sulphur compounds called glucosinolates. When you chew them, they break down into isothiocyanates, the source of that peppery bite. These compounds are being studied for possible anti-cancer effects. The National Cancer Institute says the evidence in people is still mixed.

Fibre and water. Radishes are about 95% water with a little fibre, both of which help digestion.

What's overstated

  • "Balance thyroid hormones." There's no good evidence radishes help thyroid function. In fact, very large amounts of raw cruciferous vegetables can, in theory, interfere with iodine uptake. That's not a concern at normal food amounts for most people, but it means radishes are no thyroid remedy.
  • "Cleanse the kidneys" and "detoxify the system." Your liver and kidneys do that job. A diet rich in vegetables supports them, and radishes are a fine part of it.
  • Silicon and sulphur "deficiencies". These are not recognised problems in people eating an ordinary diet.

Ways to eat more radishes

French-style. Crisp radishes, good butter and flaky salt. It sounds too simple to be a recipe, and it's one of the best snacks there is.

Roasted. Roasting mellows radishes into something sweet and juicy, like a small turnip. Toss halved radishes in olive oil and salt and roast at 220°C (425°F) for 20 minutes.

Quick-pickled. Thinly slice radishes into a jar, cover with equal parts vinegar and water plus a pinch of salt and sugar, and leave for an hour. Keep in the fridge for a week.

The avocado's creamy richness balances the radishes' heat, and its fat helps you absorb the fat-soluble nutrients in the herbs.

Don't waste the tops. Radish greens are peppery and tender when young. Sauté them with garlic, blend them into pesto, or add them to soups.

Choosing and storing

Look for firm, smooth radishes with fresh-looking leaves. At home, cut off the leaves (store them separately) and keep the radishes in a container in the fridge. They'll stay crisp for a week or more. If they go soft, a soak in iced water brings them back.

The bottom line

Radishes won't transform your thyroid or melt away pounds. They're a cheap, crunchy, low-calorie vegetable with a fair dose of vitamin C and the same interesting compounds as their cabbage-family cousins. That's reason enough to keep a bunch in the fridge.