Herb of the Month: The Stinging Nettle

A plant for the Witch’s tool bag

It was earlier last week when, tweeting about my excitement for the fast-approaching spring (less fast-approaching in Sheffield, but still…) and it’s inevitable plenitude of stinging nettles, and receiving many responses from similarly-moved herbalists around the globe, I thought I must dedicate March to this most revered of pesky garden weeds. For most people it is hard to imagine the fondness a herbalist feels for this repellent plant – it’s nasty sting is enough to make anyone take a wide berth on walks in the open countryside or ease carefully around it on narrow paths, leaving it behind with a sigh of relief. It’s scientific name Urtica dioica comes from the Latin urere meaning ‘to burn’. I don’t expect to make you fall in love with nettles – my only hope is that after reading this you will look at them with at least some degree of awe.

I mentioned last month that lots of valuable herbal medicines frequently used by medical herbalists in their clinics can be found on your kitchen shelves at home. I discussed the chemistry of culinary herbs – mainly Sage – and added a couple of recipes on the version for Beanie’s wholefoods. This month I’m going a bit further in writing about a herb that is in itself a whole, nutritious meal. The delights of nettle soup are well known among wild food foragers and herbalists, and I shall be including a delicious recipe I found recently at the end of this post.

So, the point I am coming to is:

“Let thy medicine be thy food, and thy food thy medicine”

 I’m pretty sure that was Hippocrates (the father of Western medicine), but it’s also a central notion in Ayurvedic (traditional Indian) medicine and traditional cultures across the world. It makes sense, of course. It doesn’t mean you can’t have the occasional fry-up but, generally, what you eat is what defines you and your physical and mental health. And if you start incorporating herbal medicine into your daily life as part of your diet, rather than thinking of it as medicine, your relationship with both food and medicine will change. I like this idea as it is not uncommon for people, when they are ill, to think “I can get over this by myself, I don’t need medicine” – which one wouldn’t necessarily say about food!

So over the next few paragraphs I will discuss nettles, their chemistry, some clinical studies, and give you some ideas of how to use them as both food and medicine.

Good old nettles

Nicholas Culpeper (a 17th century herbalist and activist who made it his life’s work to translate the medical texts of the time from Latin into our native English, so the British public could know how to treat themselves at home), in his 1653 Complete Herbal, advised:

“Nettles are so well known, they need no description. They may be found by feeling, in the darkest night”.

culpeperfight

Although this is an entertaining image, it is not the most useful of tips – I would recommend harvesting during the day, with gloves on. Even better – choose a sunny day and just pick the tops, for they are more tender & juicy than the lower, older leaves.

I agree with Mr. Culpeper, however, that they “need no description”. Thankfully, I have the modern herbalists’ tools of MacBook Air and wireless Internet, and can show you a real picture of them!

Stinging nettles - Urtica dioica

Stinging nettles or Urtica dioica

Medicine vs Food

Before discussing the chemical components of stinging nettles, I want to offer a loose definition of the difference between medicine (or at least herbal medicine) and food – and this comes down to what are called primary and secondary metabolites.

Primary metabolites are those produced by the plant that are essential for its growth & development. In terms of what we eat, these are either the macronutrients (carbohydrate, protein & fat), or the micronutrients (vitamins & minerals). The substantial portion of vegetables, fruits, nuts & grains are made up of these molecules, plus fibre. They are the building blocks of our diet and therefore, our cellular structure and physiology.

paleo3

Secondary metabolites, on the other hand, are those thousands of molecules produced by the plant for other reasons – survival, adaptation, self-defence, communication (yes, plants do communicate – that’s almost fact now). These are the flavonoids, alkaloids, terpenes etc; the medicinal compounds or phyto (plant) chemicals. For example, the oleoresin of Myrrh is produced to protect the tree from infection, and we use its antibacterial, astringent properties for much the same reasons.

The Myrrh tree producing its valuable resin

The Myrrh tree producing its valuable resin

Secondary metabolites are why herbalists prefer wild harvesting their herbs where possible – a plant exposed to harsher growing conditions is considered more likely to produce these self-defence-type molecules in greater abundance. And these substances remain in the plant’s tissues to be extracted during the process of herbal medicine making. Some constituents are extracted in alcohol – terpenes, for example, need a high percentage of alcohol to be best extracted – while some are water-soluble, such as the immuno-modulating polysaccharides found in Echinacea, Plantain & Marigold (Ganora 2009).

Beautiful Echinacea

Beautiful Echinacea

All fruit & vegetables, especially organic ones, contain these secondary metabolites as well, just as all fresh herbs contain primary metabolites when eaten whole. However, not many herbs are as rich in each category of substances as the lovely stinging nettle. If you’re taking a multivitamin every morning and wondering whether you really need to, just go and pick a few nettle tops and add them to your scrambled eggs instead – they are a veritable vitamin & mineral complex in their own right, and they’re FREE. The main primary metabolites, therefore, are:

 Vitamins

A: Nettles are rich in carotenes – the yellow-orange chemicals named after the garden carrot, which are produced in a plant’s leaves to protect it from damaging ultraviolet rays from the sun. These are precursors to vitamin A in our bodies and also as cellular antioxidants.

C: Also produced by the plant for its own antioxidant protection, in animals it is essential for the synthesis of important cellular structures (collagen), other antioxidant molecules (vitamin E) & nervous system hormones (adrenaline). It is thought to be the main rationale behind the traditional ‘spring tonic’ used by herbalists as a general pick-me-up after the winter months – our ancestors would use this to top up on vitamin C after their meaty winter diet. Vitamin C also helps with the absorption of iron, which may be why nettles are so useful in cases of iron-deficiency anaemia.

B1 (thiamin): The B vitamins play a part in the enzymatic processes which release energy from the digestion of carbohydrates, which explains their use by natural therapists in cases of fatigue. Thiamin is also important for maintaining the integrity of our nervous systems.

B2 (riboflavin): Also involved in energy release, soft tissue repair and the manufacture of red blood cells – perhaps another reason why nettles are used for anaemia.

B9 (folic acid): This is important for proper foetal development during pregnancy as well as blood vessel protection and again, the production blood components.

E: This is an important antioxidant at cell membranes that works in conjunction with vitamin C, and also involved in skin & reproductive health.

K: Very important in blood clotting – nettles were traditionally applied to wounds to staunch bleeding – as well as bone formation and blood sugar regulation.

 Minerals

Calcium & potassium salts: Central to bone health, this explains why nettles are used in conditions such as osteoporosis. Potassium is important as many conventional diuretic medicines (given to increase urination and thereby lower blood pressure by removing excess fluid from the blood) flush potassium out of the body – nettles can replace this potassium AND work as a diuretic (see below), so are also used in cases of high blood pressure.

Magnesium: Also very important in bone growth, nerve & muscle function.

The nitty gritty

However, it’s with the secondary metabolites that we get into the nitty gritty of nettles… so I shall discuss the main ones under their physiological interactions & clinical uses. I say the ‘main ones’ – over 100 compounds have been found in the hairs, leaves, roots, flowers & seeds! And I’m not even touching on Nettle root (used in benign prostatic hyperplasia or BPH) – that’s for another post!

Anti-inflammatory

It terms of the actual stinging sensation of nettles, its the acids in the hairs that are responsible – mainly oxalic and tartaric acid. These break down on cooking, which is why only fresh nettles sting. However, the hairs also contain amines (protein-derived phytochemicals) – histamine, serotonin and acetylcholine – that are all inflammatory mediators and neurotransmitters in animals. When stung with nettles, these amines cause local inflammation that then triggers a deeper, long-lasting anti-inflammatory effect.

This might seem paradoxical but if you think about it, when we are hurt, the body rushes to repair the wound by sending lots of immune system cells to the site of injury to clean it up and protect the rest of our body from infection. This initially causes redness and swelling – or inflammation – but the actions going on in the wound itself are anti-inflammatory. Inflammation is a necessary healing process and without it we would not last long, but in conditions such as arthritis the inflammation sticks around and does not clear up. Here, nettles are thought to stimulate the inflammatory, and therefore anti-inflammatory, process.

In arthritis it is taken internally or the fresh leaf is applied to the area to cause direct stinging. This is a great way to enjoy the benefits of nettles with minimal preparation! And it is even supported by evidence – one randomised, controlled, double blind study has been conducted, involving 27 patients with osteoarthritic pain at the base of the thumb or index finger. Patients applied fresh stinging nettle leaf daily for 2 weeks to the area, with a 5-week gap in between week 1 and week 2, and the placebo arm applied white dead nettle (Lamium album). Reductions in pain and disability were significantly greater for nettle than placebo, and the localised rash or itching from the sting was considered acceptable to 23 of the 27 patients.

Other trials have been conducted without a placebo arm – in one of them, 1340mg of nettle leaf extract (about 10g of fresh leaves) per day were as effective as a comparative NSAID (non-steroidal anti-inflammatory drug, ie. ibuprofen) treatment for arthritic pain in 219 patients (Sommer & Sinner 1996). In another, patients were able to half their dose of NSAIDs when taking 9g per day (Ramm & Hansen 1996). In an open, randomised study of 37 patients with acute arthritis, an NSAID (diclofenac 200g) was compared to doclofenac plus stewed nettle herb (both at 50g). Improvement in blood markers of inflammation and clinical signs of arthritis were seen to a similar extent in both groups, which suggests it may enhance the effect of the NSAID, allowing a lower dosage to be used.

Immunostimulant/ anti-allergic

A general decrease in inflammatory markers in the blood has also been measured in healthy volunteers given nettles (Obertries et al 1996). This indicates it could also be used for general immune dysfunction or debility. It is most certainly used by herbalists in hayfever for its anti-allergy effect. One randomised, double-blind study of 69 patients with hay fever compared the effect of a freeze-dried preparation of nettles with a placebo over a week of treatment. Patients had to record their symptoms in a daily diary and then a ‘global response’ was recorded at the end of the week. Nettle was rated higher than placebo in the global assessments, but when comparing diary data it was rated only slightly higher.

Interestingly, the hormone adrenaline (also called epinephrine) is found in the chloroplasts of nettle leaves, which is the main component of medical ‘epi-pens’ (epinephrine pens) used in severe allergic reactions to relax the airways and improve breathing.

Depurative

The traditional use of nettles, especially in springtime, is as a depurative or ‘blood cleanser’. A depurative, in herbal medicine terms, is a substance that facilitates the elimination of metabolic waste from the organs and tissues of the body – mainly the liver, gallbladder, kidneys, colon, lymphatic system & lungs. Due to the association of liver/digestive dysfunction (inappropriate elimination) with skin disorders, depurative herbs are used in conditions like eczema, dermatitis and psoriasis. There is not a huge amount of research on this, at least not connected to nettles. In one German study however, nettle & dandelion juice improved skin elasticity & hydration significantly compared to a control group after 6 weeks of treatment.

Diuretic

As the kidneys are organs of elimination, the diuretic (meaning ‘stimulating an increase in urinary flow’) action of nettles can be seen as part of its depurative properties. It is therefore useful in cystitis, to flush out bacteria from the bladder, & high blood pressure, to remove excess fluid from the body and therefore lower blood volume.

Traditionally, this is also considered part of its mechanism in relieving arthritic or rheumatic pain, such as gout – by eliminating toxins (such as uric acid) in the urine, less are present in the body to cause inflammation & pain. In one open label study, the juice of nettle leaves (10 to 20ml/day) was administered for 12 weeks to 114 patients with kidney stones & rheumatic symptoms – an increase in urinary flow along with a decrease in pain & burning on urination, as well as joint stiffness and pain, was seen.

Nettles also contain LOTS of bioavailable silica – the hairs are essentially little needles made of the stuff – which helps to restore connective tissue in both urinary & bone disease, therefore useful in conditions like recurrent cystitis & osteoporosis.

Empirical empowerment

As with many of these traditional, un-glamorous herbs found mainly on roadsides and in ditches, they are very under-researched. For one to cite the above trials as “clinical evidence” for the use of nettles in herbal medication would be misplaced – there is no robust, scientifically accepted evidence, although the research into pain relief in osteoarthritis looks promising. But there are equally few reports of negative interactions of nettles with conventional medication or as part of a herbal prescription, and medical herbalists have been using this herb since time immemorial for the indications described above. Some people are allergic to nettles – but these are specific sensitivities like the ones people get for dust or peanuts, rather than an adverse effect of the plant per se.

As with most things then, if you have arthritis, hayfever, eczema, anaemia (…) and want to try other options, why not give it a go. If the winter was just a bit too long and you need a bit of a spring in your step, whip up some soup and see what happens. For aching joints, just jump in a nettle patch! It might well help, and it’s fun, free and empowering.

On that note, I have to share a totally mad quote I found in a book called “A Woman’s Book of Herbs” by Elizabeth Brooke…

“Witchcraft makes us strong, independent, creative, thoughtful women. It connects us with life, with the earth and its cycles, and with all other witches, both esoterically and exoterically (that is, hidden and open), wherever they might be working. To become a witch, say:

I am a witch

I am a witch

I am a witch

and you will be. Blessed be.

Nettle is a plant for the witch’s tool bag. Drink it, grow it, burn it as incense. May patriarchy fall!”

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Recipes

And now to end on a more practical note (!) – I usually like to include recipes I’ve made and developed myself, but these nettle recipes I found on the guardian website by Hugh Fearnley-Whittingstall looked so good and so original I had to share them. He also gives some tips about how to collect & wash the nettles that are slightly more helpful than old Culpeper’s suggestions!

Hugh Fearnley-Whittingstall's nettle recipes

References

Bone & Mills (2013) Principles & Practice of Phytotherapy: Modern Herbal Medicine. Churchill Livingstone.

Ganora (2009) Herbal constituents: Foundations of Phytochemistry. CO, USA. Trickey (2003) Women, Hormones & the Menstrual Cycle. Allen & Unwin, Australia.

Ramm S, Hansen C. Multizentrische Anwendungsbeobachtungen mit Rheuma-Hek BrennesselblätterExtrakt bei Arthrose und rheumatoider Arthritis. Therapiewoche 1996, 28:3-6.

Sommer R-G, Sinner B. IDS 23 in der Rheumatherapie. Kennen Sie den neuen Zytokin-antagonisten? Therapiewoche 1996, 46:44-49

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