Is nettle tea healthy?

Geschatte leestijd: 10 minuten Is Nettle Tea Healthy? If so, what is nettle tea good for? In this article, we will discuss the presumed and proven health effects of nettles and nettle tea.

Nettles

The nettle (Urtica) is not exactly the most popular plant when you decide to take a walk in nature on a beautiful day. It is the only plant you learned to fear as a child in the Netherlands. The burning sensation caused by the plant’s hairs can be a nasty distraction during a fun day out. A defense mechanism of the plant caused by contact with the stinging hairs containing histamine and various acids.

Nettle Tea

Perhaps it is precisely that defense mechanism that made nettles an interesting ingredient for medicines over the centuries. By cooking or drying the leaves, the stinging hairs lose their painful effect, making them edible. The fact that you can eat it does not explain why people have wanted to eat it for centuries. However, it doesn’t take much imagination to understand why nettles were seen as a potent remedy by healers. A burning blister is annoying, but it also indicates the power of the plant. If that power can be translated into a medicine, then that medicine will also be powerful, right? Naturally, that’s not the logic with which the current pharmaceutical industry develops medicines. When it comes to nettle tea, I always think of old ladies living in the forest with 12 cats in a house made of gingerbread. Something you throw into the cauldron before going to fight Romans.

What is nettle tea good for?

The sap of nettles has been used since ancient Egypt to alleviate symptoms of arthritis and lower back pain. ‘Urtification’ is a process that has been used by many cultures throughout the millennia. In this process, one strikes themselves with fresh nettle leaves. According to the Egyptians, it was a way to treat, among other things, chronic rheumatism, coma, paralysis, cholera, and typhus. The Romans are said to have taken their own nettles to Britain to improve blood circulation and thus relieve painful legs during long marches. Older American tribes are also said to have used this treatment method. Hippocrates (460-377 B.C.) and his followers report as many as 61 treatment methods using nettles. Greek physicians described nettles as a diuretic, laxative, treatment for dog bites, nosebleeds, swellings, excessive menstruation, pneumonia, and the list goes on. In some cases, nettles were believed to accomplish all of this on their own, while in others, the combination with substances like hemp or cannabis was prescribed as a treatment. John Gerard, a herbalist from the 16th century, used nettle as an antidote. A century later, Culpeper, an astrologer and physician, suggested gargling with an extract containing honey and nettle would be good for inflammations of the mouth and throat. He also suggested that nettles could help remove bladder stones and worms in children. They were also believed to assist as a disinfecting treatment for wounds, skin inflammations, joint pain, and as an antibiotic for poisonous animal bites or stings. In the 19th century, Phelps Brown suggested the use of nettles as a remedy for dysentery, hemorrhoids, and bladder and kidney stones. The seeds could be used in wine to combat fever.

Is nettle tea healthy?

The list of effects attributed to nettles throughout the centuries is much longer. The above description seemed sufficient to show that according to our ancestors, nettles could cure just about anything. The question, of course, is what remains of all those old wisdom in current science. After all, there are plenty of ancient remedies that we have since tossed into the quackery bin. However, there are also ancient wisdom that science has only managed to prove and explain centuries later. So, let’s delve into what substances are in nettles and what effects we can actually expect from them in the form of tea.

Nettle tea ingredients

• Proteins (comparable to spinach)
• Vitamins A, B, C, D, and K
• Calcium (relatively high compared to other leafy green vegetables)
• Magnesium (relatively high compared to other leafy green vegetables)
• Iron
• Silicon
• Potassium
• Flavonoids (strong antioxidants)
• Carotenoids (antioxidants)

It is easy to imagine that nettle tea can indeed have positive effects on health. Let’s now delve into some of those effects as described by modern science.

Nettle tea against diabetes

The current obesity epidemic unfortunately comes with rising numbers of people with type 2 diabetes. Normally, insulin regulates your blood sugar. Sugars are absorbed into the blood in the form of glucose. Your body responds by releasing insulin into the blood. This travels along with the glucose and tells cells in the body how to deal with it. For example, glucose can be absorbed by muscles (in the form of glycogen) and other cells as a source of energy. Glucose can also be stored as a reserve in fat cells. However, in type 2 diabetes, these cells are less sensitive to insulin, making them less capable of absorbing glucose. The result is that your body is no longer able to regulate your blood sugar properly. According to a 2013 study, nettle tea improves blood sugar regulation in people with type 2 diabetes by stimulating the release of insulin [1]. Drinking the tea can safely lower blood sugar, both after eating and on an empty stomach.

Nettle Tea as Antioxidant

Nettle tea has a strong fighting effect against bacteria and fungi. This is due to the large amount of antioxidants in nettle tea [2]. Together with the high concentration of vitamin C, these antioxidants reduce oxidative stress on the body. Combating this oxidative stress, and the free radicals that result from it, is a function of the immune system, which is relieved in this way.

Nettle Tea as Diuretic

Nettles have likely not been used for thousands of years as a diuretic without reason. This is one of the effects also confirmed by current science, in rats at least [3,4].

Lower Blood Pressure with Nettle Tea

By losing more sodium and fluid, blood pressure can be lowered. Less blood (volume) means less pressure on the vessels it flows through. A 2012 study showed that regular consumption of (fresh) nettle tea can lower high blood pressure [5]. Nettles also contain histamine. Histamine can widen blood vessels and thus lower blood pressure [6]. Unlike lowering blood pressure by reducing blood volume, widening the vessels increases blood circulation. Oxygen supply improves in this way, reducing the risk of heart disease and heart attacks.

Nettles for Gastrointestinal Disorders

In 2007, a study was conducted on the use of plants as medicine in central Serbia, a region with a great diversity of plants [7]. Nettle was used as a remedy for various gastrointestinal disorders. There seems to be a good theoretical basis for this. The antioxidants and antibacterial properties of nettle tea could prevent an imbalance of bacteria in the stomach. In addition, worms and parasites in the intestines could be fought. This could promote the growth of good bacteria and help limit issues such as irritable bowel syndrome, diarrhea, constipation, and general stomach discomfort.

Nettle Tea and Testosterone

The effect of nettle tea on testosterone is unclear. Some researchers point to a possible lowering effect, while others suggest a possible increasing effect. Besides a potential effect on the amount of testosterone released, it can also influence how the body handles testosterone. For medicine, it is an interesting topic, although the goal is often different than for those seeking to maximize testosterone for muscle growth. Nettles contain lignans, a type of phytoestrogen that is abundant in flaxseed. These are substances that structurally resemble the female sex hormone estradiol. They have various effects on hormone balance.

• They occupy estrogen receptors
• Lignans reduce the activity of sex hormone-binding globulin (SHBG) that binds with estrogen, testosterone, and DHT
• They reduce the activity of the enzyme 5-alpha reductase
• They reduce the activity of the enzyme aromatase

Almost all of these terms are covered in an extensive article on testosterone and anabolics. Here’s a brief explanation for now. Apologies in advance for the complexity.

Biologically Available Testosterone

The hormone testosterone can bind to certain cell receptors to exert its effect. For example, with muscle cells, it instructs them to convert available amino acids into muscle proteins. This is the well-known ‘anabolic’ effect that leads to muscle growth. Not all testosterone can achieve this effect. Most testosterone binds with the protein SHBG. This means it no longer ‘fits’ on the receptor of the (muscle) cell. A smaller portion binds with the protein albumin or doesn’t bind at all (‘free testosterone’). The latter two are the ‘biologically available’ testosterone that can exert its effect. However, the lignans in nettle tea can also bind with SHBG. As a result, this place is already ‘occupied’ and can no longer bind with normal hormones like testosterone and estrogen. That means less testosterone can bind with SHBG, leaving more biologically available testosterone. That’s the theory, at least. There are also studies showing that lignans (from flaxseed) can significantly lower testosterone. However, this is in cases where it concerns a woman with exceptionally high testosterone, men with prostate cancer, and a boy who consumed 5 to 8 times the recommended 30 grams of flaxseed per day. Whether it’s relevant for nettles is questionable, although some draw that link. Nettles contain 10 times fewer lignans than flaxseed [8]. Additionally, the studies on binding with SHBG were conducted with cell cultures in petri dishes. This doesn’t necessarily translate to living humans.

5-alpha-reductase and Aromatase

Because lignans have different effects on different players in the hormonal system, it’s not surprising that studies show different results. I once discussed 5-alpha-reductase in an article about creatine and baldness. This enzyme is responsible for converting (part of) testosterone into dihydrotestosterone (DHT). DHT also works anabolically but cannot be converted into estrogen by the enzyme aromatase. The lignans in nettles can lower this conversion into DHT by reducing the activity of 5-alpha-reductase. Less testosterone converted into DHT means more testosterone, but also more testosterone that can be converted into estrogen. Purely looking at how much testosterone remains, however, one could argue that there’s more testosterone, as some researchers also did [9]. Whether that research is truly relevant for normal people is questionable. It was conducted on rats whose testosterone was raised to induce prostate enlargement. The testosterone was found to be even higher in the group that received nettle extract. However, if this is only because a smaller portion is converted to DHT, then it’s uncertain what it means for muscle growth. DHT can more easily bind with cells and therefore works stronger than testosterone. Although there’s less DHT, this DHT is more active. Like testosterone, its action can be lost by binding with SHBG. However, this binding is less due to the lignans occupying this spot. The question is which effect ultimately prevails. The lignans in nettles may also have a lowering effect on the enzyme aromatase [10]. This is the enzyme responsible for converting testosterone into estrogen. It’s a concern for users of anabolic steroids due to possible side effects (e.g., ‘bitch tits’ and water retention).

Nettle Tea and Acne

Some suggest nettle tea as a treatment for acne. Since DHT is considered one of the causes of acne, and the amount of DHT itself can (potentially) be reduced by nettle tea. As described earlier, however, the remaining amount could be much more active due to reduced binding with SHBG. The influence of remaining DHT on acne is unclear. Other reasons to use nettle tea for pimples include its antibacterial and disinfectant properties. Research has not been able to prove that nettle tea works in practice against acne.

Nettle Tea Side Effects

You can partly deduce the side effects from the health effects described above. Lowering your blood sugar is not positive if you already have low blood sugar. Or if you’re using blood sugar-lowering medication, as a diabetic, for example. The same goes for the blood pressure-lowering effect. Not helpful with an already low blood pressure or when using blood pressure-lowering medications. The diuretic property can also be too much of a good thing if you’re already using diuretics. In all these cases, you need to be aware of the potential effect to take it into account. Also, the use of nettle tea is not recommended in the following situations:

• In case of kidney stones. Especially with older leaves of wild nettles. Substances dangerous for the kidneys then increase in concentration.
• When using blood thinners. The high levels of vitamin K can interfere with the action of these medications.
• If there are existing stomach problems. Some report nausea or stomach pain after use.
• When using sleep medication. Nettles can induce drowsiness.
• Nettle tea and pregnancy? That’s not a wise option given the potential effect on hormone balance (occupying receptors where estrogen needs to do its work).

Nettle Tea, How Many Cups Per Day?

Unfortunately, there’s little to say about that because it depends on too many factors. What health effect do you want to achieve, for example? And which part of the nettle are you using and from which species? For allergies, a dosage of 600mg of freeze-dried nettle leaves per day was used in a study. In research on preventing prostate enlargement, 360mg was used daily, but then from the roots. The latter turned out to be more successful against prostate enlargement than the leaves against allergies. Apart from which part of the plant you use, where and when it’s harvested, and what you use it for, you still have to deal with the other variables to determine a dosage. Think about gender, age, weight, and allergies. Science simply still has too many questions to answer about the possible health effects in general, let alone to provide an answer to this question with all the different variables.

Making Nettle Tea

However, in general, nettles are not considered particularly risky in terms of potential toxic substances and side effects. A cup of nettle tea (or soup) from time to time can’t hurt. The good news is that you can find nettles abundantly in the right season. As mentioned, you might do well to only pick young leaves. Not only for the kidneys, but also because they are less bitter and contain more nutrients. Also, it’s a good idea not to pick along your favorite hiking trails. Those paths are probably also favored by dog owners, and I personally don’t like to pick my lunch in a dog urinal. Finally, I don’t need to explain to anyone that it’s handy to wear gloves when picking. Preparing the tea itself is very simple in any case. There are two basic methods of preparation: Boiling or drying.

Making Nettle Tea with Fresh Leaves

For every 30 grams of leaves, add about a cup of boiling water. Besides nettles, you can of course also add other fresh herbs yourself. According to some, you only need to let this steep for 10 minutes, while according to others, it takes 24 to 48 hours. After this, all you have to do is strain it.

Making Nettle Tea with Dry Leaves

It’s even easier with the dry leaves. You just steep them in your boiled water like normal tea.

Buying Nettle Tea

Walking to the store can be even easier in many cases. There are many different brands and types available. The most important thing is to go for the purest content possible, 100% nettles. If you want the benefits of nettles but hate tea, you can also eat the boiled leaves as spinach. You can also eat the roots as vegetables after boiling them. You can also add the roots to a soup. Enjoy! References

1. Kianbakht S, Khalighi-Sigaroodi F, Dabaghian FH. Improved glycemic control in patients with advanced type 2 diabetes mellitus taking Urtica dioica leaf extract: a randomized double-blind placebo-controlled clinical trial. Clin Lab. 2013;59(9-10):1071-6. PubMed PMID: 24273930.
2. J.L. Guil-Guerrero, M.M. Rebolloso-Fuentes, M.E.Torija Isasa, Fatty acids and carotenoids from Stinging Nettle (Urticadioica L.), Journal of Food Composition and Analysis, Volume 16, Issue 2,
3. Tahri A, Yamani S, Legssyer A, Aziz M, Mekhfi H, Bnouham M, Ziyyat A. Acute diuretic, natriuretic and hypotensive effects of a continuous perfusion of aqueous extract of Urtica dioica in the rat. J Ethnopharmacol. 2000 Nov;73(1-2):95-100. PubMed PMID: 11025144.
4. Qayyum R, Qamar HM, Khan S, Salma U, Khan T, Shah AJ. Mechanisms underlying the antihypertensive properties of Urtica dioica. J Transl Med. 2016;14(1):254. Published 2016 Sep 1. doi:10.1186/s12967-016-1017-3
5. Otles S, Yalcin B. Phenolic compounds analysis of root, stalk, and leaves of nettle. ScientificWorldJournal. 2012;2012:564367.
6. IDENTIFICATION OF PHARMACOLOGICALLY ACTIVE SUBSTANCES IN THE INDIAN STINGING NETTLE, URTICA PARVIFLORA (ROXB.) P. R. Saxena, M. C. Pant, K. Kishor, K. P. Bhargava. Canadian Journal of Physiology and Pharmacology, 1965, 43:869-876, https://doi.org/10.1139/y65-092
7. Snežana Jarić, Zorica Popović, Marina Mačukanović-Jocić, Lola Djurdjević, Miroslava Mijatović, Branko Karadžić, Miroslava Mitrović, Pavle Pavlović, An ethnobotanical study on the usage of wild medicinal herbs from Kopaonik Mountain (Central Serbia), Journal of Ethnopharmacology, Volume 111, Issue 1,
8. Kraushofer, T. & Sontag, G. Eur Food Res Technol (2002) 215: 529. https://doi.org/10.1007/s00217-002-0606-y
9. Nahata A, Dixit VK. Ameliorative effects of stinging nettle (Urtica dioica) on testosterone-induced prostatic hyperplasia in rats. Andrologia. (2012)
10. A comprehensive review on the stinging nettle effect and efficacy profiles. Part II: urticae radix. Chrubasik JE, Roufogalis BD, Wagner H, Chrubasik S Phytomedicine. 2007 Aug; 14(7-8):568-79.