by Liisa Korpela
Botanical Name: Urtica dioica L.
Common Names: Stinging Nettles, Common Nettle
Family: Urticaceae “Nettle” family
Parts used: Aerial tops of young leaves prior to flowering, roots and seeds
Preparations: Food (pesto, soups, sautéed greens, spanakopita,green smoothies), vinegar, infusions, decoctions, tincture, freeze-dried capsules
As the Willamette Valley is bursting with springtime, one of our favorite first foraging adventures each year is the quest for the ultimate spring green: nettles. They have a long history of use as a fiber, food and medicine. A powerhouse of nutrition, packed with vitamins and minerals, this is the perfect herb to nourish and “lighten” the body after a long winter slumber of darkness and heavy, rich, dense foods.
Botany & Chemistry
Nettles are found most abundantly in the northern circumboreal regions of the world. It grows in well-drained, rich, moist soils in habitats as varied as the desert to the woods. You can find it in gardens, next to manure-rich barns, along spring sides and riverbanks, and in woodland openings and meadows.
Nettles (Urtica dioica) belong to the family Urticaceae and genus Urtica; the Latin name is derived from the word uro, meaning “to burn.” The perennial, herbaceous, rhizomatous plant grows up to 1-3 m. Its leaves grow opposite to a length of 7-15 cm and are shaped lanceolate to heart-shaped with margins that are serrated. As the Latin name, dioica “two houses” suggests you will find this plant’s dense, axillary, green- brownish male and female inflorescences on separate plants, though occasionally they are found together. (1)
Up for debate and researched for over 200 years is the mechanism and compounds that deliver the sting from this plant. As early as 1849, the sting was thought to be from formic acid, which is the same compound found in the bite of an ant. The actual amount of formic acid measured in the nettle is too insignificant to deliver a reaction, even though it is still commonly pointed to as the suspect. Looking for more clues to the action of this sting, it was postulated that the neurotransmitter compounds of histamine, acetylcholine, and 5-hydroxytryptamine (serotonin) found in the tissues of the leaf and stems were the reason for the burning pain. Though plentiful in the leaf and stem tissue, there is only a negligible amount in the actual needle-like hair structure. It is also thought that while the neurotransmitters can create a sensation of pain and dermal reaction when brushed, they were not sufficient enough to create the lasting pain experience up to 24 hours after contact. (2)
Despite the mysteries of understanding the actual action of the stinging hair, we do know that when brushed the tip of the hair breaks off and injects a chemical slurry into the skin creating a burning sensation that can last from hours to days. Historically, this sensation was sought after for treatments of “urtication”, a flagellation technique of whipping the body with the hairy stems and leaves. Those heroic enough to endure this practice will find that the stimulation increases circulation in the area that is flogged. (3) This often results in alleviating of the pain associated with conditions of stagnation. Rudolph Weiss, an early century German specialist in internal medicine and professor of herbal medicine, suggests the topical use for chronic arthritic conditions like rheumatism, sciatica, chronic tendonitis, and sprains. (4)
History and Uses
Nettles have a long history of use as a fiber and dye plant. As a fiber plant, nettles along with flax and hemp were much more important than the popular cotton fiber and they were used as a replacement fiber by the Germans in WWI when cotton was in shortage. Textiles made from wild nettles have been found in burial sites in Denmark from 3000 years ago. (5) It has also been discovered that the shipping fiber of ropes and sails of ancient Scandinavia were traditionally made with nettle fiber. Nettle leaves and roots have also been used as a natural dye producing a green or yellow color respectively.
Nettles traditionally were used as a pot herb, which means that you can throw it in the pot with your other veggies and meats to stew them up, much like spinach. This is an excellent way to extract the minerals from the plant making an incredibly nutrient dense meal. The list of vitamins and minerals in nettles is extensive. Vitamins A, C, E, and K along with calcium and magnesium are abundant in the leaves. In younger plants, nettle bare significant amounts of iron, beta-carotene, and chlorophyll. (6) With the high mineral content of this herb, it has a wonderful benefit for alleviating cramps of the legs and menstruation resulting from mineral deficiencies.
Nettles are best to harvest during the spring as the fresh leaves come out and the stalks are young, as opposed to full maturity in the summer and fall. Later in the season, the plant develops tiny cystoliths, or calcium carbonate concentrates, that can lead to irritation of the kidneys and potentially the formation of kidney stones.
Many people are familiar with using nettles in soup, but consider other delicious and nutritious applications such as in pesto, sautéed greens, spanakopita, green smoothies, or as a sprinkle: Nettle-Seaweed Gomasio.
Besides being a powerhouse of nutrition in your food, nettles have numerous medicinal benefits coming from its leaves, roots, and seeds that can be infused and decocted among other things. The leaves have traditionally been used as a diuretic, alterative, anti-hemorrhagic for wounds and menstrual flow, and to promote lactation. More recently, nettles have been studied for their anti-inflammatory effects for allergic conditions of all types affected by pollen, mold and environmental pollutants. In an open trial study, 69 patients with allergic rhinitis (hay fever) were given 600mg freeze-dried nettle leaf daily to study its effects on their symptoms. It was reported that 58% of the participants, experienced relief of most of their symptoms, while 48% found it to be more effective than other over-the-counter medications. (7) In practice, it is considered an effective remedy for these allergic responses of sneezing and itching (eyes, ears, throat, nose). For those with allergies, it is commonly recommended to take 2-3 months prior to the peak of the season. During the allergy season some have experienced success with increasing the dose if symptoms persist.
Along with its effects as an anti-inflammatory for allergies, it has also more recently been studied to support patients with Type 2 diabetes, a chronic inflammatory disease. More research is needed to confirm these results but it shows great potential to “improve glycemic control in type 2 diabetic patients needing insulin therapy.” (8)
The roots of this herb have a history of use as a diuretic, alleviating edema, and supporting the kidneys and urinary tract. Modern research and traditional use have shown the root to be beneficial for the prostate. A study done in 2006 showed that nettle root along with saw palmetto was safer and more effective than the prescribed treatments for urological symptoms of benign prostatic hyperplasia. (9)
The seeds do not have as long of a historical use but they have been popularized by herbalist David Winston (10) for a restorative effects on kidney disease along with herbalist Johnathan Treasure who has reported and published case studies on his site of it’s potential protective effects on compromised kidneys. (11)
More research is needed to expand on this plants vast potential in the realm of phytotherapy. Through our long history with this plant, it has undoubtedly shown its value in our daily lives. Nettles have provided fiber, food, and medicine for millennia to those who live in close proximity to it. To think about it in the big picture of its benefits and uses, we can approach this plant as suggested in the wisdom of herbalist David Hoffman, “When in doubt, use nettles.” (12)
1. Hitchcock & Coquist. 1973. Flora of the Pacific Northwest. University of Washington Press. Seattle, WA.
2. Han-Yi Fu, Shiang- Jiuun Chen, Ruei-Feng, Ling-Long Kuo-Huang Chen, Rong-Nan Huang “Why do nettles sting? About Stinging Hairs looking simple but Acting Complex.” Functional Plant Science and Biotechnology: Global Science Books 2007
3. Grieve, M. A Modern Herbal Vol 2. Dover Publications, New York, 1971, pp. 574-579
4. Weiss RF. Herbal Medicine, 6th ed. Beaconsfield, England: Beaconsfield Publishers Ltd; 1988: 261-262
5. Bergfjord, C., U. Mannering, K. M. Frei, etal. “Nettle as a distinct Bronze Age textile plant.” Scientific Reports 2012. 2:664.
6. Upton, Roy Stinging Nettle (Urtica dioica L.): Extraordinary vegetable medicine Journal of Herbal Medicine Vol 3, Issue 1, March 2013; 9-38
7. Mittman P. Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis. Planta Medica 1990; 56-44-47
8. Kianbakht, Saeed, Frarhnaz Khalighi-sigaroodi, and Fataneh Hashem Dabaghian/ “Improved Glycemic Control in Patients with Advanced Type 2 Diabetes Mellitus Taking Urtica Dioica Leaf Extract: A Randomized Double-blind Placebo-controlled Clinical Trial.” Clinical Laboratory 59, no. 9-10 (2013): 1071-6
9. Rapp, Cathleen. “Special Saw palmetto and Stinging Nettle Root Combination as Effective as Pharmaceuticl Drug for Prostrate Symptoms.” American Botanical Councils HerbalGram Issue 72 2006; 72:20-21
10. http://www.davidwinston.org/extracts/stingingnettleseed.html Accessed May 5, 2016
11. Treasure, Jonathan. “Case History: Nettle Seed and Kidney Function.” Accessed May 15, 2016 http://jonathantreasure.com/evidence-research-testimonials-case-history/case-histories/nettle-seed-kidney-function/.
12. https://www.youtube.com/watch?v=eqBTUke22us Accessed May 5, 2016