Is it safe to eat buckwheat every day

Rather than make you read through the entire post to get to the answer I will give the short answer here: buckwheat is safe to eat buckwheat every day. 

I had a few people ask me about the possibility of issues from eating buckwheat every day, most of these questions have been surrounding a compound called fagopyrin.  I am not an expert, and I am not a food scientist, so I did a bit of research, and decided to write what I found in a blog post so I can find it again.  

Too much fagopyrin over a long time period can cause phototoxicity, which is a sensitivity to sunlight and causes skin issues.  I was not sure how much is too much.  Many plant based foods have some level of toxins or anti nutrient.  I am not a food scientist ad didn't have more than a basic level understanding of the topic, so I did some reading into how safe buckwheat really is.  The results were interesting but not overly surprising.  

Common buckwheat with heart shaped leaves

Buckwheat seed has been eaten by people since at least the year 6,000 BC.  There have been few reliable reports of people having issues due to consuming buckwheat.  Based on this information alone, buckwheat seed appears to be safe to eat.  The actual answer, however, is more complex than a simple yes or no.  

Buckwheat seeds, sprouts, leaves, stems, rhizomes, and flowers have all been important sources of food or medicine for thousands of years, over the past few hundred years it has also been used as animal forage or silage.  

Consuming buckwheat has been demonstrated to help prevent various chronic illnesses, such as hypertension, obesity, cardiovascular disease, tumors, and gallstone formation.  Various pharmacological studies have confirmed that buckwheat holds anti-diabetic, anti-tumour, anti-inflammatory, antioxidant, and hepatoprotective effects.  All of this is great, but still doesn't answer if it is safe to eat buckwheat every day, or how much is too much.  

There are some reports of animals experiencing phototoxicity due to buckwheat's fagopyrin content.  These animals ate nothing but buckwheat stems, leaves, and flowers for weeks on end, which means that this only proves that like everything else too much is not great.  To put this perspective, if I ate nothing but apples for weeks on end I would become dreadfully unwell.  The question still remains, how much buckwheat is too much?  

Anecdotally I can say from experience that eating buckwheat groats every day is safe.  I have been eating grechnevaya kasha every day for breakfast for around two years, during that time I have become healthier in measurable ways (lower cholesterol, better LDL:HDL ratio, more stable blood sugars etc).  Buckwheat is highly nutritious, it is simple to prepare, and I like the taste.  

Anecdotal evidence based on personal experience is fine, but it doesn't answer the question over how much is too much, and actual evidence is always far better than anecdotal evidence.

Raw buckwheat groats

There have been rare reports of people reacting poorly to buckwheat seed, many of these have been food allergies.  The reports of skin sensitivity issues are almost entirely from people consuming large quantities of sprouts (and sometimes flowers) over an extended period of time.  So far I have found no reliable reports of anyone experiencing fagopyrism from eating hulled buckwheat seeds.  

When looking at the massive number of people who eat buckwheat seed as a staple food (hundreds of millions of people), and the extended period of time this has occurred (thousands of years), and the relatively few instances of problems, buckwheat appears to be safer to consume than wheat, milk, or eggs.  From this we can conclude that eating buckwheat is safe, but this still doesn't answer the question of how safe is buckwheat, or how much is too much.  So I did some more reading and crunched some numbers to actually answer these questions.  

Reliable data in peer reviewed papers on the fagopyrin content of buckwheat seed is scarce, and there is almost no information on the phototoxic dose in humans.  

The literature states that in leucistic/albino rats, slight skin issues start to be seen when feeding around 2.5 to 3 mg fagopyrin per kg body weight (with severe issues starting between 5 to 10 grams per kg body weight).  While humans are not rats, and most people have more melanin than these leucistic rats, this is the best analogue we currently have. 

The lowest end of this range, feeding 2.5mg/kg body weight extrapolates to 150mg of fagopyrin as being safe for a 60kg person.  I realise that extrapolation does not always work in a perfectly linear way, and this is based on the amount that causes issues in leucistic/albino rats rather than people, but it is the best we can do considering the surprising lack of human research.  I also realise that most people weigh considerably more than 60kg, so this acts as a bit of a buffer.  

Buckwheat leaf on right, fishmint on left

Fagopyrin is present in different amount at different stages of growth, and different concentrations are found in stem, leaf, flower, seed, and hulls of buckwheat.  While there are discrepancies in the literature about the amount of fagopyrin detected, there is general consensus that buckwheat seed contains the lowest concentration of fagopyrin.  

Several papers have reported detecting up to 0.07mg per gram in raw Tartary buckwheat groats.  Tartary buckwheat is Fagopyrum tataricum they did not specified if they were dehulled or included hull.  I am yet to find any mention of detectable amounts of fagopyrin in common buckwheat (Fagopyrum esculentum) groats.  While I assume these higher results may have included the hull, thus increasing the fagopyrin content and decreasing protein content, I am going to use the highest number in my calculations.  

While I am yet to find any paper where dehulled common buckwheat (Fagopyrum esculentum) groats had any detectable level of fagopyrin, and while I am not able to buy anything other than dehulled common buckwheat, to err on the side of safety I am going to use the highest levels detected from Tartary buckwheat in my crude calculations.  

If we use the lower safe amount of 2.5mg fagopyrin per kg bodyweight, and take the higher amount of 0.07mg/g fagopyrin possibly being contained in the seed, this would mean that a 60kg person would not run into issues with fagopyrin unless they eat over 2.1kg of raw buckwheat groats to reach the 150mg safe thresh hold.  

Given that it is likely that the amount of fagopyrin is lower than 0.07mg per g of common buckwheat grain, and that it is also highly likely that most adults would weigh considerably more than 60kg, and that most people have at least some melanin in their skin, combined with the fact that it is unlikely to eat more than 2kg of (cooked or uncooked) buckwheat per day, it seems reasonable to conclude that buckwheat grain is safe to consume either raw or cooked, so long as you are not allergic.  

Based on the above, it appears that buckwheat groats are safe to eat every day, either raw or cooked, in any amount you like.  

Pink flowered buckwheat setting seed

Eating buckwheat leaf, or rhizome, or sprouts, or flowers, may be a different story.  

While buckwheat leaves have been eaten as vegetables for thousands of years, and many millions of people still eat leaves, stems, flowers, and rhizomes of buckwheat regularly, they have almost exclusively been cooked in some way.  

There seems to have been some research conducted into raw leaves and stems as they have been used as animal fodder.  Unfortunately, while papers possibly exist, I have been unable to find any research into the fagopyrin content of cooked buckwheat leaves.  If you can direct me to a peer reviewed paper on this please let me know and I will update this blog post accordingly.  

I found an old paper stating that "based on a comparison to hypericin toxicity, the recommendable intake of buckwheat sprouts was estimated to be less than 40 g per day".  This statement is often quoted and is rather misleading at best.

The findings from that paper are regularly quoted when referring to the safe amount of raw buckwheat sprouts to eat.  People often extrapolate that to conclude the same safe limit applies to buckwheat leaves, or even groats, when this is not the case.  Strangely enough, the '40g per day' thing is not even the safe limit when dealing with buckwheat sprouts. 

Hypericin is a chemical found in St John's wort, it is similar to fagopyrin, but not the same.  Rats showed skin sensitivity when fed 0.5 mg kg hypericin, as opposed to fagopyrin which needs to be fed at 2.5-3mg per kg before any slight reaction is noticed.  

Given that studies indicate that hypericin is far less toxic than fagopyrin, I am not sure why this comparison was ever made, and it makes little sense as to why it is so often quoted.  If anything, this data would indicate that at least five times that amount (ie 40g x 5 = 200g) should be completely safe to consume regularly.  That paper also stated that raw buckwheat sprouts contained far higher levels of fagopyrin than leaves of mature plants.  

For these reasons I decided to ignore that often quoted 40 gram number and tried to do my own (also potentially flawed) calculations. 

Perennial 'golden' buckwheat autumn colours

The leaves of Tartary buckwheat have been recorded in one study as containing 0.512mg per gram.  This means it would be safe for a 60kg person to consume at least 292 grams of raw leaves per day for quite some time before any adverse effects would be possible.  

The same study recorded the fagopyrin content in common buckwheat leaves as 0.322mg per gram when in the vegetative phase, meaning it would be safe for a 60kg person to consume at least 465 grams of raw leaves every single day.  It is noteworthy that when in flower, common buckwheat leaves contained higher amounts of fagopyrin than they did before flowering.  Flowers contain significantly more fagopyrin than leaf and stem.  Most forage fed to animals has been from buckwheat that was flowering, which is partly why fagopyrism has been seen in livestock.  

In that same study, the leaves of perennial buckwheat were recording as containing up to 0.947mg per gram.  If it is safe for a 60kg person to consume over 150mg of fagopyrin per day, it would be safe to consume at least 158.39 grams of raw perennial buckwheat leaf every day before there could be possible issues.  While this is the lowest amount out of the three species, it is quite a lot of leaf to eat every day.  

It is noteworthy that several studies demonstrate there is a reduction in the amount of fagopyrin after steaming Tartary buckwheat seeds.  I can't find any papers indicating if fagopyrin levels of leaves are decreased with cooking.  I am also not sure why the fagopyrin was decreased from steaming.  I don't know if it is degraded by heat, or if some of it leaches out into the water and drips away.  While there is a lot I don't know, this is noteworthy nonetheless.  

Perennial buckwheat is used as a leaf vegetable

It is also noteworthy that the few cases of fagopyrism in humans I have read about were due to drinking copious amounts of 'green smoothies' made from raw sprouted buckwheat daily over a long time period.  Most of these reports did not specify if the hull was included in the green smoothie.  

These people reported tingling when sunbathing, most noticeable under their arms, some had tingling around their mouth, others were easily sun burnt, a few had rashes or even blisters after prolonged exposure to sunlight.  These people reported that simply reducing the amount of buckwheat sprouts in their smoothies was enough to eliminate this issue.  This means if you did over do it and ate too much for too long, it should not be difficult to reverse any issues that you may encounter.  

Based on the above, it appears that buckwheat leaves are safe to eat in moderation.  The amount that a person is likely to consume seems somewhat lower than the amount you would need to consume to encounter any issues, and to have any problems you would need to consume these large amounts over a significant amount of time.  If you eat a somewhat balanced diet, and not just buckwheat leaves (or lots of green smoothies), I think it would be difficult to reach the level where you could potentially encounter any issues.  

From the literature it appears there is next to no chance you could ever eat enough dehulled buckwheat groats to experience any issues with fagopyrism, and that leaves are safe to eat in moderation.  

Tokyo Bekana cross Bok Choy

Bok choy and Tokyo bekana are both varieties of Brassica rapa.  This means that these nutritious cabbages can and do cross pollinate very easily unless care is taken to prevent this.  

These are both highly nutritious vegetables, both are very simple and fast to grow, and seed of both is readily available and reasonably simple to save.  Both of these should be considered in any home vegetable garden. 

Last year I grew them both, along with various other winter greens and wrote a comparison of them.  I isolated them to collect some pure seed to grow the following year.  As well as this I made some deliberate crosses between them.  The photo below shows the two parents I used in this cross.  

Bok choy and Tokyo bekana

Below is a photo of bok choy on the left, Tokyo bekana on the right, and the cross in the middle.  It is pretty obvious that the cross is different from Tokyo bekana and bok choy. 

Not surprisingly, this F1 cross was pretty much part way between the two parents in all respects.

The plant looked similar to bok choy, but a lot larger, and a bit messier in growth habit.  The leaf edges in the cross were slightly crinked or slightly wavy.  

The petioles (white stems) of the cross are far larger, and the white veins are far more noticeable than the bok choy parent.  

The green colour of the leaf (which is not easy to see in the photo but is pretty obvious in real life) is part way between the darker green of bok choy and the vibrant lettuce green of Tokyo bekana.

The leaf texture was pretty much half way between the two, not as crunchy as Tokyo bekana and not as...I don't know the word...as bok choy.  

The taste of this cross was basically half way between bok choy and Tokyo bekana.  It tastes nice, which was expected given both parents taste nice.  

Bok choy on left, cross in middle, Tokyo bekana on right

I like both of the parent plants, and I like the cross between them.  

The cross tastes good, and it is just as easy and fast to grow as either parent.  It was not bothered by pests any more than either parent (we get slight issues from cabbage white butterflies, but nothing too serious), and it was significantly larger and more productive than the bok choy parent.  

Even with all its benefits, I am not sure if I will bother stabilising this cross.  I might keep growing it and stabilise something, but at this stage that seems unlikely.  I like both parents, they are both great, so unless something unexpected happens the cross may be the end of its line.  

Tokyo bekana bok choy cross with both parents

That isn't to say that I am not considering to re-try this cross.  I think if I ever re-do this cross I would use different parents, and would get a better result faster.  I would probably still use the Tokyo bekana, but if I were to try this cross again I would use a different variety of bok choy.

There are many varieties of bok choy, ranging from micro dwarf Hedou bok choy (which I grow and enjoy), all the way to some reasonably large varieties.  

I used a baby bok choy in the above cross, and the hybrid was significantly larger than that parent.  If I were to try this cross again I would try to track down the largest bok choy I could find and use that as the parent.  Perhaps this combination could produce a very large bok choy.  

A very large bok choy could be worth growing, and could provide some benefit to growing it alongside the parent varieties.  

There is a vegetable called De Zhou cabbage, I believe that Tokyo bekana was one of the parents that contributed to this variety.  I am tempted to get this to use as a parent in crosses, and am tempted to create my own version, and am also tempted to let this slip and just grow the plants I have.  So far I have not decided what I will do.  

Bok Choy Tokyo Bekana - cross breeding

As well as the deliberate cross above, I allowed some plants to open pollinate, set seed, and drop seed by themselves.  I mostly let them flower for the pollintors, and planned to remove them before seed set, but some got away from me and dropped some seed.  There were a few different varieties of B rapa flowering, all of which could easily cross with one another as no attempt was made to isolate them.  

I didn't have a lot of space to spare, so couldn't allow many self seeded plants to grow.  From those that were not removed I got some vigorous volunteer plants, most were true to type, and a few were clearly crossed.  

We have been eating all of them and feeding all of them to the chickens.  Some are better than others, anything substandard will be removed before flowering as I don't want substandard genetic getting into the gene pool.  

One of the random crosses that I may keep had a noticeable purple smudge, and a slightly purple tinge to the petioles and leaf veins.  It is difficult to see in the photo below, but the purple is there.  The colouration is far more noticeable in real life. 

Slight colouration in the veins and petioles

Given the shape and colouration of this plant, my guess is the seed parent was purple stemmed hon tsai tai, and the pollen parent may have been Tokyo bekana.  Both of them are Brassica rapa so are simple to cross.  Interestingly enough, I was considering trying that cross but didn't actually get around to it last year.  

The taste of this plant is nice enough, certainly better than most leafy vegetables I can buy.  While good, it is nothing to rave about.  The taste is not as sweet as hon tsai tai, and the texure is not as crisp as Tokyo bekana.  At this stage I prefer both parents to their cross.

Purple smudge is more noticeable in real life 

The plant itself is too messy looking for my liking, while it is more productive than hon tsai tai it is not productive enough, and there is not enough colour.  I am not overly fond of this plant, but it is only F1 at this point.  Future generations could segregate and have any/all/none of the characteristics I want.  I plan to bag this plant so it self pollinates, and I will attempt to collect the seed.  

The F2 seedlings should show a lot of variation, and from there I can decide if I want to continue this line or to start again.  Only highly coloured, highly vigorous plants that taste nice are to be kept.  Perhaps I won't keep any and will feed them all to the chickens, only time will tell.

Large flowers in dense heads

Messy, reasonably productive, large leaves

I like hon tsai tai.  The leaves taste almost sweet, and the purple colour is rather pretty.  I find the plants are a bit too messy looking, and for me it is not productive enough to grow as as a leaf vegetable, but the taste is very good.  When grown for the flower stalks like broccoli, the hon tsai tai can be very productive and can send up many flower stalks.  The taste of these is good, far better in my opinion than true broccoli. 

The hon tsai tai in the photos below was self seeded.  It had a lot of competition, very poor soil, and has not grown to its potential.  It gives you an idea of the colouration.  You may notice the leaf petioles have a deep colour, and the veins only have slight colour, this seems to vary from plant to plant and I am not sure if this is due to genetics or is largely environmental.  Had I picked this flower stem it would have sent up a lot more very quickly.  

I am not sure if I will allow this plant to set seed, I am leaving it for now as it is one of the few things that is flowering at the moment.  I like to have a few things always flowering to feed to local pollinators.  Pollinators seem to love brassica flowers, and hon tsai tai can grow many flowers over an extended period.

Purple stemmed hon tsai tai

Hon tsai tai colour

Another cross I have considered is hon tsai tai with bok choy.  I would like a compact neat looking bok choy with coloured stems.  I have some bok choy with green stems, others with white, but nothing with vivid stems and green leaves.  

I am not sure if the outcome is achievable, or if the project will just end in substandard unproductive plants.  I know a few other people have tried similar breeding projects, and have developed things like 'vivid choy' or 'rainbow tatsoi'.  I think vivid choy looks messy, and does not seem to be a huge improvement to hon tsai tai.  

I love the shape of bok choy.  To me it is one of the prettiest vegetables.  If I breed anything that loses that bok choy shape, I think I may be better off not using bok choy in the breeding program at all and may be better off using one of the many other versions of  Brassica rapa that are available.  

Sometimes I sell seed of some of these vegetables through my for sale page.  I should bag some flowers and offer a few of the varieties that I grow as they are nice to eat and very nutritious.  Most are pretty common, others such as senposai are far less common.  

Tokyo Bekana cabbage looks like lettuce

Tokyo Bekana (Brassica rapa) is an interesting leaf vegetable that deserves to be grown more commonly.  It's a highly nutritious cabbage, but it looks like a lettuce.  If you have never tried this, you should grow it and see if it makes its way into your yearly vegetable garden growing rotation.  

I have only been growing Tokyo Bekana for a year or two, and am very impressed with this almost obscure vegetable.  

I think there are a few different varieties of Tokyo bekana around.  The one I grow looks slightly different to the varieties they grow overseas.  Mine looks far more like lettuce, which is what I prefer. 

Tokyo bekana leaves 

I find how uncommon this vegetable is to be really baffling.  This quick and easy to grow vegetable is basically unheard of in Australia, yet it is super simple to grow, tastes good, is very nutritious, and seed is often available from many seed companies.  While you may have more luck in other areas, I have never seen Tokyo bekana for sale in fresh food markets.  

Like many vegetables, it has a few different common names.  I have seen it called 'vitamin green' due to its high vitamin content.  I have seen it called 'space cabbage' as it has successfully been grown in the space station as a trial vegetable (it had issues with high levels of CO2).  Tokyo bekana seems to be the most commonly used name for this vegetable, so that is what I call it.  

Tokyo Bekana

Toykyo Bekana is an Asian cabbage (Brassica rapa).  I like many of the Asian cabbages, and Tokyo Bekana is one of my faviourites.  It looks like lettuce but is far more nutritious, it never goes bitter, and it grows incredibly fast.  

I have read that Chinese cabbages were first introduced to Japan in the very early 1900's by soldiers returning home after the Russo-Japanese war.  These cabbages were selected for desirable characteristics, and crossed, and selected some more, until Tokyo bekana was developed and stabilised.  I am told it is still widely grown in and around Tokyo.  

Self-seeded plant

This year I didn't get around to planting seeds of many winter greens.  What you see in these photos are mostly the results of things I let drop seed over summer, and have popped up by themselves.  I did deliberately plant some seed, but not enough.  

I am glad that Tokyo bekana self seeded.  I have been picking them for many weeks and I expect to be able to keep harvesting until it is time to dig them in and plant my summer vegetables.

Self seeded winter vegetables

I dislike many of the European cabbages (Brassica oleracea).  I like some more than others.  While there are exceptions, I usually find their taste and smell to be displeasing.  I find them simple yet slow to grow, and their fresh leaves seem to irritate my eyes.  

Perhaps I am imagining that part about them irritating my eyes, or maybe it is a real thing, I don't know for sure.  It seems as though every time I handle cabbages my eyes are irritated.  The leaves have a bloom of fine powder that I think is irritating my eyes, then again perhaps this is a placebo effect and I am imagining it.  

There are a lot of different types of European cabbages, but that is a long and (incredibly interesting) story for another time.

Tokyo bekana is an Asian cabbage.  Asian cabbages (Brassica rapa, and a few other species) are a different species, and I tend to like them a lot more.  There are a few Asian cabbages that I dislike, and there are many types that I do like.  I usually find their taste more agreeable, many grow almost unbelievably fast, and they don't seem to irritate my eyes (although this last point may be imagined).  

There are also vast numbers of different types of Asian cabbages.  The story of Asian cabbages is incredibly interesting - that's right Jarvis, or Jeremy, or Travis, or whatever your name is, the cabbage story is super interesting!   

To me the Tokyo bekana plants looks a lot like lettuce.  They are an attractive bright green, the leaves are slightly crinkled, and they have a soft crunchy white mid rib.  

All parts are tender and edible.  They are picked and eaten at any stage from micro greens, to baby leaf, all the way to impressively large plants.  The leaves never get tough or fibrous, and they don't get bitter or spicy.  

It looks so much like lettuce

You can eat it raw like lettuce (yes, I know you can cook lettuce) and it goes well in things like garden salads and Caesar salad.  When raw it makes a decent lettuce substitute, tastes vaguely similar, yet is far more nutritious and easier for me to grow.  

You can stir fry it or use it in any way you would use Bok Choy.  It tastes different to bok choy, but still very good.  When stir fried it tastes nice, it goes well with pretty much everything, and when cooked it reduces in size considerably.  It goes reasonably well in shchi (Щи) but lacks volume once cooked.  While I haven't tried this I'm told it can also be fermented and made into sauerkraut or kimchi and things like that.  

Tokyo bekana lasts a few days in the fridge so is probably best harvested as needed, one leaf at a time.  You can cut the entire plant to harvest, but you get a far larger crop over a longer time period by just taking leaves as needed.  Picking as needed eliminates any worry with storage.  

I didn't thin them, and they are very productive

Tokyo bekana grows very fast.  Last year I recorded the number of days from planting seed until harvest, it took just over a month from planting the seed until harvesting baby leaf, and a little under two months until I was harvesting large plants.  Most 'days to harvest' are recorded from transplanting seedlings of undefined age, I recorded days from planting the seeds until harvest as that is far more useful for me to know.  

For me they grew through winter with no significant issues.  It copes well with frosts and cold weather.  

Once the weather heated up they went to seed.  I allowed it to drop some seed in the garden, where it did not grow over summer.  Once the weather cooled the volunteer seedlings started to pop up.  

Bok choy and Tokyo bekana from same age plants

I think Tokyo bekana can grow well over summer if given enough water, when allowed to self seed it waited for autumn to germinate.  

I am told that this is a biennial, and under the right conditions it possibly is, for me it grows as an annual.  For me, most of the Asian cabbages are annuals, and most of the European cabbages are biennials.  I prefer annuals to biennials as seed saving is easier/faster when dealing with annuals. 

As Tokyo bekana is the same species as bok choy (and a lot of other Asian cabbages) they can and do cross readily, so care needs to be taken with seed saving.  

I did a control cross of Tokyo bekana and bok choy out of curiosity.  The cross was far larger than the bok choy parent.  I might save that topic for another blog post rather than making this one too long.  

Bok choy on left, cross in middle, Tokyo bekana on right

Tokyo bekana looks like lettuce

When Tokyo bekana experienced a lot of frosts (down to about -8C) I found some of the outer leaves got a little damage.  It got small discoloured circles on some outer leaves, these were not a big problem.  They could be ignored and just eaten, or I could cut out those parts, or the leaf could just be fed to the chickens and I could pick the next leaf as it was protected and showed no signs of trouble.  

Being a brassica, they are eaten by caterpillars of cabbage white butterflies.  This plant does not seem to be their favourite host and I rarely found any caterpillars or much damage on the leaves.  I never spray with anything, so cabbage white butterflies can sometimes be an issue here.  Given how little damage was done to Tokyo bekana, the cabbage white butterflies were not a big problem an nothing to really worry about in my garden.  They may prove to be a bigger issue in other gardens, or when this plant is grown over summer.  

My plants have not had any issues from slugs and snails, but they look like they type of plants that snails would love.  This is probably worth keeping an eye on as they look like the kind of plant that snails would enjoy.

  

More Tokyo benaka

Our chickens love to eat Tokyo bekana, so any leaves that are damaged are fed to chickens who convert them into eggs.  Being high in vitamins, Tokyo bekana is good to use to supplement the chicken feed.  I can't imagine it is high enough in energy, so I wouldn't try to replace a high percentage of their feed with it. 

I don't tend to feed much of any brassica to our guinea pigs, the few small leaves I have given them were quickly eaten.  I dare say that many other leaf eating animals would enjoy eating these too.

These leaves are tender even when they grow very large.  I mostly feed excess vegetables to the chickens, but sometimes add a leaf to the compost where it disappears quickly, or put a leaf in the worm farm where it is eaten fast, or dig in to the soil as green manure before planting the next crop.  I image these leaves consist of a large percentage of water, and they contain a lot of minerals, so it stands to reason that they would break down fast.  

I think there are a few varieties of Tokyo bekana, the one I have is not named but grows true to type and performs very well.  I don't have any seed for sale at the moment, but may isolate and save seed from my best plants later in the season.  If I have spare seed I will try to list it on my for sale page.  

Seed for Tokyo bekana is readily available through many online seed sellers, so if I do not have any listed for sale it is worth tracking down somewhere else.  I wouldn't bother buying seedlings of you see them for sale as these grow very fast, and a packet of seed is generally cheaper and it gives you a lot more plants than a punnet of seedlings.