Radish: nutrition facts and health benefits

Radish

The pink radish is a white-fleshed root vegetable whose skin color and shape can change. Some varieties have a round root, others an elongated root with colors ranging from pinkish white to scarlet red. This subtly pungent vegetable can be consumed raw and cooked. Radish fanes are edible and offer multiple culinary possibilities.

History of radish

Although its origin remains somewhat obscure, it’s thought the radish comes from the Middle East or Southwest Asia. It would have been domesticated thousands of years ago before spreading to the rest of Asia and Europe. This vegetable was already known in Egypt before the pyramids were built more than 5 000 years ago. It’s possible, however, that it was grown mainly for its seeds, which produce a quality edible oil. The Greeks and Romans enjoyed it and cultivated several varieties. In the Middle Ages and in the Renaissance, it was the most common root vegetable in northern Europe and England, especially since it was thought to have many medicinal properties. However, people had to wait until the eighteenth century before the small round and red radishes which we know today appear. The radishes commonly eaten were generally white or black, much larger and elongate in shape.

The radish was introduced to America in the early years of colonization and has never lost its popularity since. However, we consume much less than our ancestors and the choice of varieties is now relatively small. In the nineteenth century, in the gardens of Canada and the United States, black radish, daikon and various types of Chinese radish were grown. A variety of “Madras radishes” was also grown, which has the characteristic of rapidly rising into seeds and forming edible pods. Farmers also produced a yellow-fleshed radish, which is no longer traced today, as well as a very large forage radish that was fed to livestock.

In contrast, radish has never ceased to play an important role in the diet of Japanese, Chinese and Koreans. They prepare it in all sorts of ways, in particular by marinating it in salt or miso, which allows to prolong its conservation. In Japan, radish alone accounts for almost a third of all vegetable production.

In China, some radish varieties are also grown for their seeds, which are extracted from oil, while in the Middle East, others are exclusively for their leaves, which are prepared as spinach.

Radish health profile

The radish, whether red, black or white (daikon) is a crisp, refreshing, slightly spicy vegetable. Its leaves are also edible. Like most of the crucifers, it contains antioxidants and bioactive compounds protecting against certain cancers.

The benefits of radish

Several epidemiological studies have shown that high consumption of vegetables and fruit decreases the risk of cardiovascular disease, some cancers and other chronic diseases. The presence of antioxidants in vegetables and fruits could play a role in this protection.

Cancer. Several studies have shown that regular consumption of the Brassica family’s vegetables (e.g. radish, turnip, cabbage, cabbage, cauliflower, broccoli) may prevent certain cancers, such as those of the lung, ovaries and kidneys (for women).

Active compounds contained in white radish (isothiocyanates) demonstrated antimutagenic properties in vitro, which would have a role to play in the prevention of cancer. Several antioxidants contained in radishes, including anthocyanins and kaempferol, would provide protection against cancer by decreasing the formation of tumors among animals and the growth of cancer cells in vitro. Researchers have also demonstrated that black radish antioxidants have an effect on the lipids of the intestinal cells and contribute to the prevention of colon cancer.

Cardiovascular health. Daily consumption of Brassica vegetables would be associated with a lower blood concentration of homocysteine, which would reduce the risk of cardiovascular disease. A study among animals indicated compounds from white radish (isothiocyanates) decreased the growth of vascular cells, whose development is associated with certain cardiovascular diseases. Some radish antioxidants may decrease cholesterol, triglycerides and blood glucose would also protect against the oxidation of blood lipids in animals.

Digestive system. Several studies among animals have shown that root and radish leaves contain substances that may accentuate intestinal motility.

Memory. A study conducted among older women concluded consumption of brassicas would slow down cognitive decline.

What does the radish contain?

Antioxidants

Radish contains different types of antioxidants, compounds protecting body cells from damage caused by free radicals and preventing the development of cardiovascular diseases, certain cancers and other diseases related to aging.

The red radish contains anthocyanins, mainly pelargodinines, while the white radishes contain kaempferol (a flavonol). The different varieties of radish also contain peroxidase, an antioxidant enzyme. These compounds have demonstrated in vitro and among animals promising effects for the prevention of cancer, but other studies are necessary to determine whether the effects would be similar among humans.

Glucosinolates

Like the majority of the brassica vegetables, the radish contains glucosinolates. Radish glucosinolates have the ability to transform into active molecules (isothiocyanates) when the food containing it is chopped, chewed or in contact with the intestinal bacterial flora. However, the cooking of the brassica vegetables results in a loss of glucosinolates in the cooking water.

The black radish would contain two to five times more glucosinolates than some red or white radishes. Many of these molecules would help to limit the development of certain cancers. However, other studies must be conducted to verify whether these properties apply to humans.

Brassicas and thyroid cancer: a link between the two?

The crucifers naturally contain thioglucosides, substances which would have a connection with thyroid gland cancer among animals. However, a meta-analysis of studies from many countries, involving more than 5 000 people, showed that high consumption of brassicas was not associated with greater risk of thyroid cancer among humans.

Precaution

Irritable bowel syndrome

Some people with irritable bowel syndrome may feel, in varying degrees, intolerance towards the crucifers, such as radishes. Limiting or avoiding fermentable foods such as those in the Brassica family may alleviate symptoms (abdominal pain, bloating, diarrhea) among people with this syndrome. When the symptoms are mild, or during periods of “remission”, it’s sometimes possible to gradually reintegrate these foods, always respecting individual tolerance.

Interaction between the crucifers and certain medications.

Indoles, naturally occurring compounds in the brassica vegetables, can notably reduce the action of some analgesics such as products containing acetaminophen (Tylenol, Atasol, Tempur, etc.) and other medications combining a mixture of active ingredients (Benylin, Robaxacet, etc.). People who consume a large amount of Brassica vegetables must take this aspect into consideration.

Choice and conservation

Choose

Choose firm, smooth roots and a beautiful shiny color. The leaves must be very green. To avoid unpleasant surprises, press the flesh with your thumb; if it yields pressure, the radish is probably hollow and fibrous.

The red and black radishes are easily found in the trade. The other types, including the snake radishes, are rarer: go to Asian grocery stores, which also offer radishes marinated in salt or miso.

Keep

Refrigerator. Four to seven days in a plastic bag or container filled with cold water. Keep fanes separately in the refrigerator, if you wish to consume them; the radish will keep them longer. Asian radishes and black radishes can be stored for a few weeks or even months in a perforated plastic bag.

Organic gardening

By sowing various varieties of radish, it can be consumed for a good part of the year. Very early in the spring, we sow the small red radishes of round shape, then a little later, the “French” radish, more elongated, which resists better to the heat. In July and August, the varieties of long conservation are sown: black, daikon, red or green Chinese.

To reduce the risk of illness, practice a rotation of four years (cabbages and turnips are of the same family and should therefore be taken into account in the rotation).

The soil must drain well, be hoed in depth, especially for elongated radishes, and have been enriched with manure or compost the previous fall.

PH: 6.5 to 7. It is important that the PH is quite high, especially if the cabbage hernia is present in the vegetable garden.

Lighten so that the distance between the plants is 2.5 cm to 12 cm or 15 cm, depending on the variety.

It is essential to irrigate the spring radishes in order to promote rapid growth and delay the run. In addition, radishes that grow too slowly are often hollow and excessively pungent.

If the frost threatens, cover the plants with a agrotextile. This type of cloth will also protect them against the larva of the turnip fly, which digs tunnels in the root and makes it unfit for consumption.

Spring radishes should be harvested preferably when they are small, otherwise the plant may rise into seeds and give woody and hollow roots. On the other hand, winter radishes remain tender even when they are very large; so they can stay in the land much longer. They will only be harvested when they are stored in the cellar or in the refrigerator.

Ecology and environment

A study published in 2002 by researchers at the University of Ohio indicates that the genetic traits of cultivated radish varieties can be transmitted to wild varieties and persist for at least six or more generations. Thus, genetically modified radish varieties to be resistant to diseases, insects or herbicides could transmit their characteristics to wild radish varieties. This would entail a real risk of making them virtually indestructible weeds, that is, neither insects, diseases, nor herbicides can overcome them.

The wild radish is one of the hundred plants considered to be the most damaging on the planet. In areas where the wild radish is already a problem for crops, this resistance could lead to considerable losses. One of the authors of the study therefore warns biotechnology companies against the temptation to develop genetically modified radish varieties that possess these traits.

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