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A friend sent over an advert, for “Clean Resveratrol from Japanese Knotweed”. She asked me if this looked like a business opportunity for Japanese Knotweed Solutions. My response was a resounding “no”.
I’m not suggesting that this particular product or any other resveratrol supplement has any health risks associated with it – that’s beyond my expertise. My main point is to address my friend’s question, which will also highlight (including to manufacturers of supplements based on Japanese knotweed) the potential issues in exploiting UK Japanese knotweed as a source of dietary supplements for human consumption.
For those who don’t know, resveratrol is a compound found in foods including peanuts, pistachios, grapes and wine, cocoa, dark chocolate, cranberries and blueberries. It has been shown in high-dose animal studies to have benefits for diabetes, however, Harvard research and info from Healthline indicates that a diet rich in resveratrol offers no health boost for humans and the doses in the animal trials were equivalent to the resveratrol content of between 100-1,000 glasses of red wine (sign me up for the human trial!).
I found a number of web links singing the praises of resveratrol, often citing laboratory studies on the chemical properties of resveratrol, or animal studies – but none I found had any double-blind studies showing health benefits in humans. Coincidentally, many of these sites just happened to include links to supplement sites or actively sell such supplements themselves (with some resveratrol products retailing at £30 for 60 capsules). Very convenient.
My main concern is: what is actually in these supplements, and where does it come from? The answer to this question could reveal risks of potential contamination with a variety of undesired chemicals and toxins (although again, to be clear, I have no evidence of contamination in any supplement on the market).
Reading up on these products, it seems that most are manufactured from the Japanese knotweed rhizome (the underground root system). Some sellers on other platforms actually market dried Japanese knotweed rhizome for sale in the UK.
Japanese knotweed is listed on Schedule 9 of the Wildlife and Countryside Act, which means that it is an offence to plant or otherwise cause it to grow in the wild (but not an offence to have it growing on your land). Government guidance states that “Soil or plant material contaminated with invasive non-native plants … may be classified as controlled waste.” Pieces of rhizome as small as 1g can re-grow into viable plants.
While potentially the above provisions would allow for the plant to be grown agriculturally in the UK, I have never come across a farmer who would consider planting Japanese knotweed on their land – partly because of the legal risks, the potential costs associated with legal action if the plant is allowed to affect or spread into a neighbouring property and the potential diminution of value (and difficulty securing mortgage funding) associated with having Japanese knotweed on your land. I suspect that the production and “harvesting” costs might well significantly outweigh any sale value of the “product”.
The question of the legality of transporting Japanese knotweed in the UK if it were being sent for processing into supplements (and therefore being treated as a “product” or “goods” rather than as waste) is an interesting one, and another question that’s outside my expertise, but this is where that the potential opportunity would arise for Japanese Knotweed Solutions. It would be a brave contractor, though, who wanted to try this without some very compelling legal advice!
JKSL carry out screening works on some sites, where the rhizome is separated manually from the soils and is disposed of at licensed landfill, with the rest of the soils being re-used or managed on site (but not treated as “clean”, and generally with a requirement for five years of monitoring to ensure any regrowth is managed effectively).
Such materials might seem to be perfect for supplement makers and a contractor would potentially be able to charge manufacturers for the material while also saving money on landfill costs.
However, the important thing to be aware of is that these plants and the soils that they come from are generally not treated with any care, let alone the levels of care that would be expected from e.g. a Red Tractor approved farm producer supplying the sort of products you would find in a UK supermarket. On the contrary, many of the sites JKSL work on are actively treated with herbicide ingredients including formulations which are not suitable for agricultural use – these herbicides are often translocated – meaning they are absorbed into the plant’s root system.
I am aware of a site which was reported by the landowner to be contaminated by Japanese knotweed and foraged on an industrial scale – the site fencing was cut through each time it was reinstated and the rest of the site vegetation had been cleared by the foragers to facilitate harvesting of the small Japanese knotweed shoots, which took place every couple of weeks during the growing season.
While the landowner was keen to carry out remediation by the book, they ended up refraining from applying herbicide to avoid any negative effects on the people who were carrying out the foraging (at least to my knowledge). However, it’s easy to imagine a less scrupulous landowner taking matters into their own hands or getting herbicide treatment carried out without regard for the people who were (illegally trespassing and) foraging the plant.
It’s also worth noting that not all approved UK herbicide formulations are as relatively benign for human health as glyphosate application. Some herbicides approved for use in the UK have serious potential health effects, including “may be fatal if swallowed and enters the airways”, and compounds which “may be toxic to a fetus at doses which are toxic to the mother”. I’ve also spoken on the phone to landowners who have proudly told me about killing Japanese knotweed using chemicals including paraquat (a banned, lethal herbicide) and diesel.
This is why I would always advise people against foraging Japanese knotweed (especially as there’s quite the crossover between people with a penchant for foraging and those who have a strong aversion to pesticides of any sort!).
The content of Japanese knotweed rhizome relies on soil quality as well as what happens above ground. Japanese Knotweed Solutions regularly works on sites where the soils are classed as hazardous, containing materials as diverse as asbestos, heavy metals (things like arsenic, lead and mercury) and various other chemicals including PAHs (including potentially carcinogenic compounds and chemicals that can cause blood and liver problems at high exposure) and TPH (a category covering hundreds of chemicals including petrol, diesel, benzene, fluorene and toluene).
This should provide ample explanation for why Japanese Knotweed Solutions would never consider providing any materials from our works to producers of goods for human consumption!
We would strongly encourage manufacturers of these products to consider whether they have suitable measures in place to audit the origins of the Japanese knotweed materials used in their products to ensure that they have not been treated with herbicides and that they have come from sites whose soil profile is known to be demonstrably clear of potentially harmful substances.
There is a quote on one particular resveratrol supplement, “If people let the government decide what foods they eat and what medicines they take, their bodies will soon be in as sorry a state as are the souls of those who live in tyranny”, I would counter with my own point of view “If you let people cut corners, and produce and market whatever they want, you get contaminated baby milk (more than once), horsemeat lasagne, BSE, asbestos in baby powder and junk food in schools, to name but a few.”
Government regulation of the food chain is critical in maintaining acceptable food standards and identifying and remedying the sorts of health hazards which otherwise would continue unchecked.
While we are experiencing crisis levels of obesity in the UK, I would argue that this is down to too little control, taxation and regulation of nutritionally poor foods and their marketing as governments consistently struggle to effectively tackle cheap and harmful junk foods, often marketed to children, and to facilitate healthy family life with access to good quality ingredients and lifestyle that encourages home cooking and elicits the documented benefits of mindful, social eating.
The evolution of government food and farming standards across the years, including the Food Safety Act 1990, Food Hygiene Regulations 2006 and Natasha’s Law, as well as the increasing control and professionalisation of herbicide application and the development and implementation of integrated pest management has brought us from the “wild west” of food adulteration in Victorian England to the trusted and safe systems we live with now (and in many cases that we have EU law to thank for!).
Chris Oliver
Operations Manager, Japanese Knotweed Solutions
