Debunking the myth of stinging nettles and dock leaves

Image credit: Copyright by Kenneth Allen. CC BY-SA 2.0. The image shows stinging nettle on the left and dock leaf on the right.

It is the 2020 Corona virus lockdown and I am teaching online from home. Trying to keep things a bit interesting I am putting together small experiments to do at home. While thinking about possible experiments for the topic ”Acids and Alkalis”, I remember something I was taught myself in primary school. The sap of dock leaves is supposed to relieve the symptoms of nettle stings.

Me and many other children around the world were taught that stinging nettles sting because their poison contains acids. The sap of dock leaves is supposed to help because it is alkaline and neutralizes (cancels out) the nettle’s acid.

Perfect! I thought and was very excited to have found a great activity for the children. Finding stinging nettles and dock leaves and investigating their properties at home.

However, I did some further reading and quickly realized that I would not be able to use this activity.

The leaves of stinging nettles are covered in tiny hairs. When you brush against them their tip breaks of and they turn into tiny needles injecting the venom into your skin. It is true that the venom contains acids like formic acid oxalic acid and tartaric acid. Nevertheless, scientists argue that their concentrations are too low to cause any pain.

Today the bad guys of nettle stings are believed to be three compounds that are found in our own bodies as well. Serotonin, acetylcholine and histamine. Serotonin and acetylcholine are produced by our nervous system where they carry messages between nerve cells. But when injected directly into our skin, they cause irritation and pain. Histamine is probably the worst of the trio, causing inflammation and allergic reactions to the skin. The effect or nettle stings is most likely due to a nasty combination of all three. However, in some nettle species tartaric acid and oxalic acid are thought to at least contribute to a longer duration of the pain.

Now we know that the pain and itching of nettle stings is not really caused by acids at all. But what about the alkali part? Is dock leaf sap really alkaline? The answer is no. It has also been suggested that dock leaves may contain antihistamines to cancel out the effect of the histamines, but there is no evidence for this either.

The effect of dock leaves might simply by attributed to the sap cooling the irritated skin or a placebo effect. However, there is some evidence that dock leaves could contain a chemical that reduces the effect of serotonin in the nettle venom.

What are zoonotic diseases and what does the destruction of rain forest have to do with it?

Image credit: David DennisFlickr: Bat in a Cave. CC BY-SA 2.0.

Ebola, HIV, rabies and the Corona virus. They all are caused by germs that can spread between animals and humans, also called zoonotic diseases.

HIV most likely originated from chimpanzees that were hunted and eaten for meat.  Similarly, Ebola is linked to the consumption of bush meat, especially bats.

The infamous Corona virus is thought to have jumped species first at a ”wet market” in Wuhan, China. Wet markets are traditional places that sell dead and live animals out in the open. These markets pose a good opportunity for a virus to jump species because hygiene standards are low and they are densely packed with people. However, the exact animal source of the Corona virus is still unknown. But bats are suspected to be involved here as well by infecting chicken, which was then consumed by humans. These winged mammals are often a source of zoonotic diseases because they live in large groups and travel far distances.

Normally, it is not that easy for a virus to jump from one species to another. When an organism gets infected a virus hijacks its cells to make copies of itself. To enter a cell, the virus has a key-like structure on its surface that will only let it into the cells of one single species. However, during the copying process mistakes are made and mutations occur in the key-like structures. With some luck for the virus one of these mutations will enable it to enter the cells of another species, for example humans. The virus has jumped species. This process is easier if hygiene standards are low and places are densely packed.

Research by scientists from the universities of Bonn and Ulm (Germany) also suggests that the destruction of ecosystems like rain forests may enable infections to jump species more easily. The researchers looked at ecosystems in Panama comparing undisturbed rain forest, smaller rain forest islands in the Panama Canal and small islands of rain forest within in an agricultural landscape.

Biodiversity is reduced in these small rain forest islands compared to intact rainforests. For example, there are fewer species of bats and rats. Therefore, individuals of the same species live closer together and are less dispersed. The results of the German research team showed that this also made it easier for different kinds of virus to spread within the populations of the remaining rats and bats giving these germs larger reservoirs. This could in turn make it easier for a virus to jump species and infect humans.

It is quite astonishing that the destruction of ecosystems could indeed influence our health by increasing the risk of zoonotic diseases like Ebola, HIV and the Corona virus.

 

Our connectedness to nature and what Christmas lights have to do with it

Image credit: M. Ehlers, pexels.com.

It has become a tradition for my fiancé and me to take a walk looking at the Christmas lights when we are at his family’s home in Derbyshire, England. This year it struck me that instead of Santas, angels, bells and stars, we saw a lot of lights showing scenes derived from nature.

There were glowing plastic deer and trees in almost every garden. Many had invested in projectors. This latest Christmas light fashion projects moving pictures of falling snowflakes onto your house, giving the impression of real snow falling. Other gardens had huge, inflatable polar bears and penguins.

I found these Christmas light choices interesting, because they seemed like an unconscious try to reconnect with nature. Right now, our Western societies are getting increasingly disconnected from nature. This means we spend less time outdoors, interact less with animals as well as plants and feel less like being part of nature.

Although, it is difficult to put numbers on our connectedness to nature, the RSPB (Royal Society for the Protection of Birds) published a study in 2013 after interviewing children aged eight to twelve. The young participants had to agree or disagree with 16 statements such as “being outdoors makes me happy” and “humans are part of the natural world”.

The report showed that four in five children in the UK are disconnected from nature. This means children spend less time playing outdoors and interacting with nature. Consequently, today’s youngsters feel less empathy for animals and plants, less responsibility for the environment and less like being part of nature.

I assume you can already guess where this is going? Exactly, disconnecting from nature is thought to result in people caring less about the extinction of species, pollution and global warming. To value something and safeguard it, you need to be engaged with it. But if we disconnect from nature, we will not care about its fate any longer.

So, disconnecting from nature is obviously bad for nature. But will it affect us humans? The answer is it does seem to affect our health. Research has linked visits to parks and other green spaces in cities to better mental and physical health. Some of the health benefits are obvious. If you spend a lot of your time in parks, you are more physically active. Nevertheless, a lot of research still needs to be done on this subject to find all the links. The main message is: We humans also profit from a good connectedness with nature.

Back to our Christmas light story. As a society we are disconnecting from nature. Still people choose a lot of nature scenery for their Christmas lights which shows that people still value nature in a way. The Christmas lights I saw felt like they romanticised animals and plants like a memory from better days a long time ago.

This is where I want to remind people, that nature is still here. Yes, we are losing many species and ecosystems, but all is not lost yet!

Deer still roam across a great number forests and meadows in the Northern hemisphere and the last time I checked we still had trees too. If we decide to protect and safeguard our local ecosystems, there is no need to buy plastic copies of its animals and plants. We could experience real animals and plants for free. The RSPB has a few tips for those wanting to protect their local wildlife and ecosystems.

If we decide to effectively fight climate change with real, lasting changes to our lifestyles and economies, there is no need to project falling snowflakes onto our houses. We could have real snowfall for free. The campaign Sustainability for All has some very good suggestions on how to fight climate change with simple lifestyle choices.

So, what can you do to reconnect and stay connected to nature?

Indoors, buy and grow plants in your house, apartment, balcony or garden. Watch nature documentaries. Read books about animals and plants. Feed birds in your garden or on your balcony.

Outdoors, go to the local park for a walk or a run, look for plants and animals you don’t know and google them or look them up elsewhere. Take your kids, encourage them to play in the mud and look for plants as well as insects. Go to the zoo. Go to the country side for a walk, a run or a bike ride. Go to the local beach or lake for a swim in the summer instead of the indoor swimming pool.

There are countless possibilities. Find the ones you enjoy most.

But whatever you do, do not get glowing plastic deer and trees for your garden!

3 Ways You Can Save the Bees

Image: Bumblebee (probably Bombus terrestris) by Tony Wills. CC BY-SA 3.0.

It is a warm, sunny day in May here in Uppsala. When passing the meadows close to my house you can see busy butterflies and bumblebees collecting nectar from the flowers. Watching this scene, it is almost impossible to imagine that many insect species and especially bees are actually in serious trouble. Since 2006 bee keepers in the US and Europe have seen a decline in the numbers of honeybees that is growing more rapid. This phenomenon is called Colony Collapse Disorder (CCD) where adult worker bees disappear from their hives leaving behind the queen, the brood and nursing bees.

Now, you might say: ”I do not like honey anyway. Why should I care about the bees?” Well, bees are not only involved in the production of honey, but most edible plants you can find in your local supermarket. Most agricultural plants, i.e. fruit, seeds and nuts (see here for a complete list),  rely on the pollination by bees, most of all by honeybees. As a consequence, no bees means no food for humans either which is why we should care about the bees.

What happens when bees disappear completely, can already be seen in China. Bees have become extinct in some parts of the country. For this reason farmers have started to manually pollinate fruit trees themselves in order to save their crops and buisenesses.

There are different reasons for the mass extincition of bees that we see today. The main villains are modern agriculture; germs and parrasites, particularly the varroa mite, as well as climate change (yes, the most famous super-villain). I have tried to collect some tips on how you can help to save the bees.

1 Buy Organic Food

I know this sounds very cliché and green millitant. But one huge problem for bees are pesticides, especially so-called neonicotinoids. Pesticides shorten the bees lifespan and damage their ability to reproduce. In addition, neonicotinoids have been shown to impair worker bees orientation abilities which is why many cannot find back to their hives. Also, monocultures that dominate modern agriculture are a huge problem for bees. Monocultures decrease food variety and only bloom during short timespans leaving the bees hungry for the rest of the year. Organic farming renounces the use of pesticides and monocultures, which is why eating organically grown food is a good way to help the bees.

2 Plant Wild Flowers

As mentioned above agricultural monocultures are damaging for bees. But you can do something against this by planting indigenous wild flowers in your garden or on your balcony. This way you can create safe havens for bees offering food with a good variety. In addition, you will also help other struggling insect species, for example butterflies. Be aware, that this effect can not be achieved with ornamental garden flowers like roses or pansies, as these can not function as a food source for bees and other pollinating insects.

3 Fight Climate Change

Climate change is affecting bees in a number of ways. Warm winters, extreme temperature fluctuations and earlier flowering phases cause massive stress, damage their circulation and make them more vulnerable to parasites like the varroa mite. These factors will most likely get more severe in the future with continued global warming. To prevent this you can do, what you might already do to fight climate change: Use the bike or public transport instead of the car. Take the train for long distance travel instead of the plane. Switch to an electricity company that provides you with energy from renewable power plants.

Now, go and save the bees! And your own food…