Sunday, August 4, 2013

A plant you eat and a plant you wear








Species name: Linum usitatissimum

Common name: linen, flax

Location: teaching lab at Western

One of the courses that I've been involved with as a TA (and sometimes a guest lecturer if I'm lucky; the professor of the course trusts me enough to "let me loose" on the students every so often and I LOVE it!) is called "Plants as a Human Resource", or the equivalent of the Western version of Economic Botany at other universities and colleges. It's a great course, and one where, if the students care enough to pay attention, the information is not only incredibly interesting but also applicable to everyday life. They learn about where paper comes from, where their clothing comes from, where their food comes from, where the drugs that they take come from, where their beverages of choice come from, and how agriculture first started (along with a bunch of other topics interspersed along the way). It's a really fantastic course! Flax is one of the plants that the students learn about because it has been an invaluable resource to people all over the world for thousands of years. It was domesticated in the Fertile Crescent, an area that extends from Saudi Arabia all the way to Pakistan and India. This crescent-shaped area has been responsible for the domestication of many of our invaluable crop species, both plants and animals, like wheat, rye, cotton, flax, oranges, grapes, and opium poppies. Yes, opium really is an invaluable crop species! Think about how awful surgery would be if you couldn't be prescribed morphine, or even codeine? Both come from the opium poppy!

So why is flax such an important crop? It's not just for its nutritional value, as many people in North America today are aware of. Flaxseed is a great source of omega-3 fatty acids, which have been shown in some clinical studies to lower blood cholesterol levels. The evidence for this claim isn't strong anymore, since some studies have shown that the effect is stronger for women, while others have shown this effect is only noted in men. When clinical trials don't agree with each other, it calls all of the evidence for a specific claim into question. There has been another study that has shown that the consumption of relatively high amounts of ground flaxseed can stunt the growth of prostate tumors in men, but this has never been demonstrated in other clinical trials. Yet another study has shown that ground flaxseed can help people suffering from diabetes because it can stabilize blood sugar levels (another medical claim that has never been shown in another clinical trial). One thing that flaxseed definitely can do is act as a laxative when taken with water. The seeds of this plant contain an incredible amount of fibre, which acts as a "cleanser" for the large intestine. If excessive amounts of flaxseed are consumed without water, it will instead lead to intestinal blockage. There are other, more effective natural products used in laxative medications because they don't rely so much on water intake (such as senna, carob and tamarind) so ground flaxseed is rarely the main ingredient in herbal medications for constipation. Using ground flaxseed as a home remedy is strongly discouraged; if not enough water is consumed for it to be effective and intestinal blockage occurs, it can lead to death if not caught in time. Pardon the pun, but that would be a...poopy way to die.

Aside from its nutritional value, flax has been used for millennia for its other main use and for its other common name: linen. The stems of this plant contain bundles of fibres that run the entire length of the stem (up to 90 cm of useable fibre). They are easily extracted using a microbial decomposition process known as "retting", where the stems are essentially left to rot in the field. Microbes will decompose the parts of the stem around the fibre bundles, but because they don't have the ability to digest the fibres themselves they leave them alone. After a few days, the long fibres can easily be separated from the rest of the plant and they can be cleaned, dyed, and spun into thread or yarn. Linen fibres are very strong but very light at the same time, and much more breathable than cotton. Because the fibres themselves are so long, linen garments also resist wrinkling which has made them historically desirable for "travel clothing". So how long have we been using this plant for cloth fibres? Well, the answer to that question is now up for debate after a discovery in a cave in the country of Georgia. It was originally thought that linen was domesticated about 10,000 years ago and used sparingly prior to that time (the plant was much shorter, so producing cloth from the fibres was much more labor-intensive; the domestication process imparted characteristics of longer, larger fibre bundles in a taller plant), but bundles of fibres that were spun into thread, dyed, and tied into bundles was dated from the Georgian cave to be over 30,000 years old! That's some old thread. Ancient Egyptians mastered the art of spinning linen fibres into thread and using that to make cloth; all Egyptian mummies were wrapped in linen cloth. Unfortunately, the paper-making process has stripped "unimportant" mummies of their post-mortem clothing, as the first pulps used to make paper used linen fibres (and where the name "rag bond paper" comes from). I can only imagine how important paper must have been for people to go into tombs to steal mummy rags! Sounds like a creepy and gross job.

Aside from food and fibres, this plant also has a role in traditional herbal medicine, especially in Austria. There, it was used either as a tea-like beverage or as a oily skin compress to treat a whole slew of disorders from gout and rheumatism to asthma and the common flu. None of these medicinal qualities have ever been demonstrated in clinical trials, but if you think rubbing some fresh-ground flax on your skin will treat your rheumatism, go for it. It certainly won't make it worse!

Flax flowers are the national emblem of Northern Ireland, and the national flower of Belarus.