Nettles!

Stinging Nettles: Urtica dioica

“If they would drink nettles in March
and eat mugwort in May
fewer young ladies
would go to the grave”
– in John Murrell, A Garden of Herbs, 1621

Nettles are the quintessential herb for getting over winter in my book.  They push their way up in early spring, despite a dusting of snow.  The small ones are bright and vital and don’t have quite the sting to them. But their roots mine the soil for minerals, often missing after a long winter without fresh greens, and they have an intense green taste.  The magnesium in the leaves is especially helpful if you have the winter blues.  And if you have aches and pains from the cold winter, you can whack them away with nettle stems.

Urtica dioica, the stinging nettle, is a herbaceous perennial flowering plant, native to Europe, Asia, northern Africa, and North America. It is ubiquitous in temperate South America where it was introduced and is the best-known member of the nettle genus Urtica. Urtica urens is also well-known, although a broad variety of nettles are used for medicine or food.

Nettle in Flower

The stinging nettle plant has opposite lanceolate or ovate sawtooth leaves, and is dioecious (one sex or the other). Seeds are born in dense clusters.

For eating, the herb should be harvested before flowering because tiny oxalic acid cystoliths can form in the leaves, which irritate the kidneys.  Cutting the plant back will prevent this.  Cystoliths are not present in alcohol tinctures or teas.

Energetically nettles are cool, dry and neutral in temperature.  They tonify Kidney yin and go to the lungs, blood, kidney/bladder, prostate and the bones.  The leaves make a superb blood and capillary tonic.  The roots and to a lesser extent the leaves go to the prostate.  The seeds are a superb kidney trophorestorative which means they bring the organ into balance and restore its function.  They have a wide variety of nonspecific actions, but I would not call them an adaptogen because they do not go specifically to balance the HPA axis.  They are alterative, mildly antibacterial, anti-inflammatory, mildly astringent, a non-irritating and potassium-sparing diuretic, a styptic, galactagogue, and nutritive food-grade herb.

Nettles have been used all over the world for food and medicine.  Nettle, called Stiðe in Old English, is one of the nine sacred plants invoked in the pagan Anglo-Saxon Nine Herbs Charm, recorded in the 10th century where it was made up into a salve for the wounded.   When I was in China, I was perplexed to find nettles growing on the wild sections of the Great Wall, because in the four hundred herbs I’d studied for my Oriental Medicine degree, nettles were missing.  Since this is one of the most commonly used herbs of the western materia medica, I figured that nettles must not grow there  if it wasn’t in Bensky’s Materia Medica.   But Flora of China indicates that 30 species of nettles, (荨麻属, qian ma shu) are found in China including U. diocia and U. urens and three are found everywhere.  In China nettles are used as fodder, for rope-making and that the young leaves are used as a seasoning substitute for sorrel.  All good uses, but I would be surprised if it were not used for a cooked green or for kitchen medicine.

Milarepa, green from nettle soup

Milarepa, one of Tibet’s most famous yogis and poets, transformed himself from a murderously vengeful black magician, to one of Tibet’s most respected and humane heroes after a period of austerity training.  Milarepa spent 12 years in the cold high mountains, meditating and living only on soup made from nettles and herbs, which are conventionally portrayed as turning his skin green.  (Don’t worry, it doesn’t actually happen.)  In Sikkim, Nepal and parts of north India, a nettle soup known as shisinu is a staple.

Ayurveda considers nettle to be a pitta (fire) balancing herb. It is referred to as “Chinese nettle”.  According to Eyton Shalom, “Late Winter and Early Spring in Ayurvedic thought are both dominated by Kapha-the Water Element: moisture abounds, there is rain or snow, and then in Spring the snows melt and rivers rage. This increases the strength of Kapha within us, making the body prone to problem of dampness and phlegm. Whereas in late Autumn and Early Winter it was appropriate to eat heavier tonifying food, now is a good time to gradually ease into lighter, cleansing, “Kapha Pacifying” food, like steamed vegetables, quinoa, mung dal, brown rice. Nettles are an excellent choice, as like all green “super” foods they “nourish the blood” and at the same time “cleanse” it.”

Nettle pasta. Serve with Nettle pesto.

I love eating nettles. When I lived in Genova we made them into green pasta regularly and the green is more intense than with spinach pasta, as well as being more medicinal. I  mix the leaves with holy basil and pine nuts to make a medicinal pesto.  They steam or saute well as a potherb.   The fresh nettles can be marinated in olive oil with garlic and tamari, which wilts the stingers enough to eat them raw.

I also use the dried leaves.  Don’t forget to dry some to crumble into soups, omelets and to make into overnight infusions. I throw them into spaghetti sauce, infuse vinegars to bring up the mineral content and throw them into most everything.  I even use them as one of my coffee herbs, added instead of substituted for the coffee, but bringing up the mineral content and flavanoids.

Overnight Infusion of Nettles

If I am using it medicinally or to build blood, I take a cup of crushed nettle leaves and simmer them covered in a liter of water for five minutes.  Then I leave the  covered pan on the stove to infuse overnight.  I strain it in the morning and put it in my water bottle and drink it at room temperature or use it as a soup stock.  The resulting tea is a dark green and is intensely nourishing.  It is best served unsweetened, as the mineral salts work better as a savory drink.

Nettles sauteed with onions

Nettles are quite nutritious, containing vitamins A, C, K, magnesium, iron, potassium, manganese, silica, and calcium.   The magnesium and serotonin in the herb are relaxing.  The flavonoids and carotenoids are antioxidant. The plant contains up to 40% protein, high for a leafy green herb.  Nettle works as a galactagogue by nourishing the breastfeeding mother.  It is also used as fodder to increase the milk in cows.  The mild astringency of the herb does not appear to negatively affect lactation.

Nettles infusion appears to have an antidiabetic effect.  Diabetic wistar rats fed the extract had 13% lower blood sugar when given large amounts of glucose and a 50% lower glycemia after 3 hours than controls.  It hasn’t been tested on humans, but the traditional use of nettles in Moroccan cuisine for diabetics was the inspiration for the study. However the effect on lowering blood sugar was well enough accepted that a Canadian study investigated the mechanism, concluding that urtica peptides significantly increase glucose uptake without increasing insulin secretion.

Other studies have found that nettle leaves reduce undesirable blood lipids, prostate cancer, urinary tract infections, and allergic rhinitis.

Nettle leaf extract works for arthritis and rheumatic disease because it contains active compounds that reduce TNF-α and other inflammatory cytokines. It has been demonstrated that nettle leaf lowers TNF-α levels by potently inhibiting the genetic transcription factor that activates TNF-α and IL-1B in the synovialtissue that lines the joint.

But the leaf is not the only part used.  The roots have been successfully used for benign prostate enlargement and for bacterial prostatitis.  The seeds have been found hepatoprotective (at least for rats with aflatoxin-induced liver damage) because of their antioxidant effects.  David Winston found that nettle seed would reverse or stall much kidney damage even due to glomueronephritis, a condition heretofore not considered reversible by western medicine.  There has been a small human trial on nettle seed and kidney damage by Jonothan Treasure, referenced below.  While it is unknown whether it affects diabetes-induced kidney damage, I believe I have seen such results, albeit in a small number of patients with diabetes-induced protein in the urine.

Hairs, or trichomes, on nettle stem

The stinging hair of the nettle is called a trichome, a small, shaft-like silica cell containing irritating compounds which is located on the stem and the leaves.  The  shaft punctures the skin, but the tip breaks off easily, allowing the spine to inject the juices under the skin.  The stinging toxin from this species of nettle is a combination of chemicals, including formic acid (oxalic acid or tartaric acid in some species) histamine, acetylcholine and 5-hydroxytryptamine.  Generally people try to avoid this.

However if you have rheumatoid or osteoarthritis, stiff joints or other conditions that would benefit from invigorating the blood, consider urtication. Urtication is achieved by lightly flogging or brushing the stems of nettles against the skin, applied as a counter-irritant. (Do not hit too hard or the trichomes will be crushed without entering the skin.)  The nettle used this way is a rubefacient.  Similar to the effects of gua sha or cupping, the skin turns red, blood rushes to the surface and the immune cascade is engaged. It helps release substances through the skin, increases heat locally to the joints and brings pain-relieving substance P to the skin, depending upon the place and nature of stimulation. Mashed plantain leaves or chickweed or jewelweed, applied topically will draw out and antidote an excessive sting.

Nettle leaf close up

For urtication, it works best to use stems of nettles in the field. You can pick them earlier, but they lose power within hours. In fact even keeping them standing in water directly after picking allows the spines to wilt. Urtica urens, despite its smaller leaf, may be superior for urtication because it has more dense hairs.  I pick long stems for urtication from patches grown in full sun where the stingers are stronger. I usually pick them barehanded to get a little invigoration in my hands (more about that below.) But if I let even the strong stems sit around for too long the sting you get is so tepid that it doesn’t make a decent counter-irritant.

When I was a child, a thick patch of nettles grew by the outhouse where we camped. It was easy to bump up into the nettles while jumping up and down impatiently to use the facilities, resulting in many a sting. My grandmother taught me that if you grasp a leaf firmly, you push down the irritating hairs and don’t get stung. (This works better with leaves than stems.)  It is the mindless brushing up against the plant that causes the sting. So engage with your nettles:

Tender-handed, stroke a nettle,
And it stings you for your pains.
Grasp it like a man of mettle,
And it soft as silk remains.

Sources:

      Flora of China.

Urtica

Wikipedia  Nettle Stinging Nettle, Milarepa

Bounham, M, et al. Antidiabetic effect of some medicinal plants of Oriental Morocco in neonatal non-insulin-dependent diabetes mellitus rats. Hum Exp Toxicol. 2010 Feb 12.

Domola, MS, et al. Insulin mimetics in Urtica dioica: structural and computational analyses of Urtica dioica extracts Phytother Res.

Westfall R.E., Galactagogue herbs: a qualitative study and review. Canadian Journal of Midwifery Research and Practice. 2(2):22–27. (2003)

Teucher T, et al. Cytokine secretion in whole blood of healthy subjects following oral administration of Urtica dioica L. plant extract. Arzneimittelforschung 1996 Sep;46(9):906–10.

Obertreis B, et al. Ex-vivo in-vitro inhibition of lipopolysaccharide stimulated tumor necrosis factor-alpha and interleukin-1 beta secretion in human whole blood by extractum urticae dioicae foliorum. Arzneimittelforschung 1996 Apr;46(4):389–94. (Published erratum appears in Arzneimittelforschung 1996 Sep;46(9):936.)

Riehemann K, et al. Plant extracts from stinging nettle (Urtica dioica), an antirheumatic remedy, inhibit the proinflammatory transcription factor NF-kappaB. FEBS Lett 1999 Jan 8;442(1):89–94.

How to cook stinging nettles

Wayne’s World  Plants with Stinging Trichomes

Eyton Shalom, Stinging Nettles in Soup and Medicine

Nettle leaf close up image

Feasting in the Skagit Foodshed

Treasure, J., Urtica semen Reduces Serum Creatinine Levels, Jr. American Herbalists Guild, 2003:4(2):22-25

Winston D. Little-known Uses of Common Medicinal Plants.     Proceedings of Southwest Conference on Botanical medicine.Tempe, Arizona:Southwest College of Naturopathic Medicine and Health Sciences; 2001:113-115.

 


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13 thoughts on “Nettles!”

  1. Thank you for the intelligent critique. Me and my neighbour were just preparing to do some research about this. I am very grateful to see such great information being shared freely out there.

  2. Hi – love your post – can you refer me to some research results / papers regarding the problem with the flowering nettle and oxalic acid, since here in Denmark thats not common knowledge and dried nettle (from flowering plants) are being sold in commerce.
    Best wishes,
    MARIA

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