Horseradish

In Austria, horseradish isn't known by its German name (Meerrettich); it is called "Kren". In fact, "Steirischer Kren" from Styria is a registered trademark according to the EC Council Regulation 510/2006 and is said to be a product of exceptional quality. Horseradish has a long history of use as a spice and as a medicinal plant. In addition to its culinary importance, folk medicine makes use of this aromatic taproot for treating both humans and animals. The tangy horseradish root's benefits on equine well-being have experienced a real revival in recent years. The Germany society "NHV Theophrastus" even awarded the horseradish plant the title of Medicinal Plant of the Year in 2021.

What do horseradish plants look like and where does they grow?

Horseradish (Armoracia rusticana) is now found all over Europe and Western Asia. It's even commercially cultivated in the USA and South Africa. The aromatic member of the mustard family is native to Eastern Europe. Its origins are from the region between the Volga and the Don, one of the primary inflows into the Sea of Asov. This herb grows to between 50 and 120 centimetres high. It is a heavy feeder and therefore thrives in rich soils. It can be found growing wild in damp meadows, along the edges of crop fields and on embankments. Its large, curly, lanceolate leaves are hairy and grow upright. They can grow to a metre in length and form sprawling patches. To distinguish it from similar-looking docks and sorrels, it helps to rub a leaf between the fingers. This will release the horseradish's unmistakable pungent aroma. From May until July, the horseradish plant puts out fragrant white blossoms in bunches which sprout from the leaf axils and mature into small, round seed pods. The strong root stock is made up of thick, fleshy, tapered roots that grow to 60 cm straight down into the earth, allowing the plant to survive at temperatures down to minus 50 degrees Celsius.

Despite its name, horseradish is not directly related to radishes (Raphanus); rather, it and two other species form a separate genus (Armoracia). The term "radish" is derived from the Latin radix (root) and is also used in reference to other beet-shaped roots. As to the "horse" part evidently comes from the plant's German name, Meerrettich ("sea radish"); according to the botanist Heinrich Marzell, this name refers to the Sea of Asov, the plant's native region. The botanical name Armoracia is derived from a Latinised Celtic loanword and roughly means "growing at the sea". It is then surmised that this prefix Meer (sea) was confused with Mähre, the word for an old horse, which may explain how the plant came to be known as horseradish in the English language. The Austrian name Kren is a loanword from the Slavic languages and has been part of the vocabulary since the 13th century. The Russian word хрен (pronounced "khren") illustrates the close relationship of the names and is another indication of the plant's place of origin.

What is horseradish used for?

Horseradish has been eaten as a vegetable and used as a seasoning and medicinal plant for over 2,000 years. A depiction of the plant decorates a mural at the ruins of ancient Pompeii and the Oracle of Delphi even compared it to gold. Horseradish's use in Central Europe began in the Middle Ages. Originally considered a medicinal plant, it later found use in culinary practices. This aromatic root can be eaten either fresh or dried. Its large leaves are also edible and can be prepared like any other salad greens. Its medicinal benefits are largely limited to the taproots. Horseradish root is not only prized in folk medicine, it has also been recognized as a medicinal plant by the Commission E, the German advisory board for herbal substances. The Commission recommended the internal and external application of horseradish root to treat respiratory catarrhs and acute bronchial or sinus inflammations. Its internal consumption is also recommended for treating infections of the urinary tract. External application of the pungent horseradish root promotes circulation and helps to relieve mild muscle pain. In folk medicine, a poultice made from the grated root is used to treat rheumatism, gout, and nerve and muscle pains. Persons with sensitivities should note that the root's pungent juice may irritate the skin. Horseradish is also mixed with honey to relieve coughing.

The anti-inflammatory, antioxidant, antiviral and antibacterial effects of horseradish have made it a subject of medical research, for example its application as an alternative to conventional antibiotics. Possible areas of application include treatment for respiratory illnesses, urinary tract infections, fungal infections and viral infections. Horseradish's effectiveness against bacteria such as E. coli was confirmed in the 1950s, earning it the name "garden penicillin". The German society "NHV Theophrastus", which promotes the teachings of the physician Paracelsus, named horseradish its 2021 Medicinal Plant of the Year. Of special emphasis at the presentation was the plant's strong antibacterial effect, which is gaining importance in these times of increasing resistance to antibiotics.      

What are the active substances in horseradish?

Roots that are harvested in autumn will have the largest amounts of active substances as well as the most intense pungency. The latter comes from the plant's glucosinolates – sinigrin and gluconasturtiin, which first become noticeable when the fresh root is cut into pieces. Everyone knows that grating horseradish makes the eyes water and the nose run. Breathing in a little too much freshly grated horseradish will make your entire throat burn. This is because cutting the root brings the glucosinolates in contact with the enzyme myrosinase, eliciting a chemical reaction called hydrolysis and converting the glucosinolates into mustard oils. In fresh form, these highly volatile active ingredients irritate the mucous membranes and exhibit particularly strong potency. Long storage periods or cooking will cause horseradish to lose its pungency along with much of its antibacterial power. Other important substances in horseradish root include Vitamin C, Vitamins B1, B2, and B6, iron, magnesium, calcium, potassium, and phosphorus. The root is also rich in secondary plant substances like coumarins, flavones, phenolic acids, and essential oils. These have antioxidant properties and strengthen the immune system.

Horseradish's benefits for animal health?

Horseradish is traditionally used to treat bronchitis, upper respiratory infections, and bladder inflammations in horses. Its pungent substances ensure good blood circulation in the mucous membranes and stimulate glandular activity. Horseradish's beneficial effects on metabolism and the immune system and its effectiveness against germs allow it to lend optimum support to the horse's general well-being, for example in stressful situations and during deworming treatment. Most horses have no problem ingesting horseradish preparations mixed in with their feed. However, caution is advised when administering horseradish in its pure form. Divide daily doses of horseradish into several portions to avoid stomach irritation. Follow the manufacturer's recommendations when feeding your horse ready-made products. Horseradish can also be applied to horses externally in the form of poultices to increase blood circulation in the skin and generate heat, as well as activate the healing process in cases of osteoarthritis, windgalls, and swollen legs. Please note, however, that horseradish can cause severe skin irritations and is not tolerated by some horses. Do not apply horseradish externally if your horse shows a sensitivity to it.

Sources and further reading

• Brendieck-Worm, C., & Melzig, M. F. (2018). Phytotherapie in der Tiermedizin. Stuttgart: Georg Thieme Verlag KG.
• Reichling, J., Gachnian-Mirtscheva, R., Frater-Schröder, M., Di Carlo, A., & Widmaier, W. (2008). Heilpflanzenkunde für die Veterinärpraxis. Berlin-Heidelberg: Springer Medizin Verlag.
• Die Heilkraft der Wurzeln (ISBN: 978-3-200-06312-9)
• https://www.koop-phyto.org/arzneipflanzen-lexikon/
• https://www.pharmawiki.ch/wiki/index.php?wiki=Meerrettich
• https://nhv-theophrastus.de/site/index.php?option=com_content&view=article&id=288:heilpflanze-des-jahres-2021&catid=36:pressetexte&Itemid=56
• https://web.archive.org/web/20100616213040/http://www.lmsvg.net/filebase/noindex/GGA_Steirischer-Kren.pdf
• https://de.wikipedia.org/wiki/Meerrettich