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Plant toxicity
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Treacodactyl
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Joined: 28 Oct 2004
Posts: 25697
Location: Jumping on the bandwagon of opportunism
PostPosted: Thu Apr 09, 15 5:47 pm    Post subject: Plant toxicity  Reply with quote    

Facing a welcome glut of edible flower spikes from our various perennial kales got me wondering about how much we could cope with which then led me to wonder how much might be toxic or cause other problems ...

It might sound daft but something like sorrel is known to cause problems if you consume too much but does anyone know of any research or information on such a topic?

I know PFAF often list possible hazards which I find useful (and suggests we can each as much kale as possible) but other info is always useful.

Falstaff



Joined: 27 May 2009
Posts: 1014

PostPosted: Thu Apr 09, 15 5:58 pm    Post subject: Reply with quote    

I should think kale contains oxalic acid, if you insist on going there !

dpack



Joined: 02 Jul 2005
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PostPosted: Thu Apr 09, 15 7:12 pm    Post subject: Reply with quote    

most edible greens are rather good at extracting the local minerals which can be an issue next to Chernobyl or on an old lead factory etc .

a scholar search for ld50 values can be useful when considering monodiet

Mistress Rose



Joined: 21 Jul 2011
Posts: 10983

PostPosted: Fri Apr 10, 15 6:39 am    Post subject: Reply with quote    

Sorrel contains oxalic acid, but I don't know that most cabbages do. As Dpack says, they might extract minerals, and do well on salty soil as they are descended from sea kale. Lettuce is the worst one for extracting minerals, so go easy on it if you live near a mine for lead or arsenic.

Hairyloon



Joined: 20 Nov 2008
Posts: 15285
Location: Today I are mostly being in Yorkshire.
PostPosted: Fri Apr 10, 15 7:28 am    Post subject: Reply with quote    

dpack wrote:
most edible greens are rather good at extracting the local minerals...

Aside from seeweed and for potash, has this idea ever been used for this purpose?

dpack



Joined: 02 Jul 2005
Posts: 35673
Location: yes
PostPosted: Fri Apr 10, 15 12:14 pm    Post subject: Reply with quote    

Hairyloon wrote:
dpack wrote:
most edible greens are rather good at extracting the local minerals...

Aside from seeweed and for potash, has this idea ever been used for this purpose?


yep for post industrial clean up in quite a few places.( for "ore" has been tried for a few expensive metals but im not sure how successful it was)

iirc some work has been done with algae in aquatic systems as well as soil based stuff.

BahamaMama



Joined: 21 Sep 2006
Posts: 2315
Location: Away with the fairies
PostPosted: Fri Apr 10, 15 12:27 pm    Post subject: Reply with quote    

Sunflowers are another crop that is very good for clearing toxic soils - that must make a nice change to see a field of sunnies after a dirty industrial plant.

gregotyn



Joined: 24 Jun 2010
Posts: 2007
Location: Llanfyllin area
PostPosted: Fri Apr 10, 15 1:31 pm    Post subject: Reply with quote    

I thought that oxalic acid was mainly in the beets, which was why we fed sugar beet tops to sheep, but only after wilting them for 3 days.

tahir



Joined: 28 Oct 2004
Posts: 44281
Location: Essex
PostPosted: Fri Apr 10, 15 1:54 pm    Post subject: Reply with quote    

gregotyn wrote:
I thought that oxalic acid was mainly in the beets


orach and spinach too, never heard of it being an issue in any cabbage relative.

James



Joined: 11 Jan 2006
Posts: 2865
Location: York
PostPosted: Fri Apr 10, 15 7:11 pm    Post subject: Reply with quote    

dpack wrote:
Hairyloon wrote:
dpack wrote:
most edible greens are rather good at extracting the local minerals...

Aside from seeweed and for potash, has this idea ever been used for this purpose?


yep for post industrial clean up in quite a few places.( for "ore" has been tried for a few expensive metals but im not sure how successful it was)

iirc some work has been done with algae in aquatic systems as well as soil based stuff.


Its called phyto remediation. Some plants with their associated mychoriza are good at getting rid of organics, whilst others are especially good at taking up heavy metals; they're called metalophytes. Grow them on metal waste tips, harvest, compost, dry, incinerate, collect bottom ash as metal oxides.

Tahir- this is probably one of those things where the lethal dose of kale tops is HUGE, but prolonged eating of large (but not un-imaginable) quantities could also be lethal, or at least injureous to health. Doesn't oxalic acid cause gout?

tahir



Joined: 28 Oct 2004
Posts: 44281
Location: Essex
PostPosted: Fri Apr 10, 15 8:00 pm    Post subject: Reply with quote    

Should I cut down on the saag?

dpack



Joined: 02 Jul 2005
Posts: 35673
Location: yes
PostPosted: Fri Apr 10, 15 9:49 pm    Post subject: Reply with quote    

the crystals in the joints that cause gout are uric acid,the problem is genetic ( causing a missing enzyme that normally pushes uric acid to urea)and not caused by diet although reducing protein intake and taking the correct meds reduces the problems

oxalic tends to do harm when the long sharp crystals poke holes in ones guts.the amounts (and crystal forms)in most edible greens are unlikely to do much harm but some roots (briony is a good example)protect their starch store rather well.

processing can separate the starch from the oxalic with such roots but unless you really need to it aint worth the effort.

an odd gout fact is that there was(is?)a problem in the dalmation dog population(the best kennel club spots and the missing gene seem to be on the same bit of dna iirc)

saag is usually fairly safe

Andrea



Joined: 02 May 2005
Posts: 2260
Location: Portugal
PostPosted: Sat Apr 11, 15 6:57 am    Post subject: Reply with quote    

My memory is hazy, but I seem to remember that a more worrysome aspect of oxalic acid was that it hindered the take up of iron. It was an issue when creating veggie based baby food.

You'd have to eat a tremendous quantity of veg to poison yourself with it.

Treacodactyl
Downsizer Moderator


Joined: 28 Oct 2004
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Location: Jumping on the bandwagon of opportunism
PostPosted: Sat Apr 11, 15 7:10 am    Post subject: Reply with quote    

Yes, PFAF mentions oxalic acid can block the take up of other nutrients and I thought can add to problems like kidney stones.

However, it was just a general example. When I was thinking about the kale glut I wondered if the mustard oils in it could ever cause an overdose? The plant has evolved these oils to be toxic to pests after all.

A different approach might be looking at survival situations. There's various examples of people surviving on single foods and that causing problems. If we had a blueberry glut for example and ate a large bowl everyday would that cause a problem? (Note, no pesticides will be used which is one problem that comes up when searching).

Nick



Joined: 02 Nov 2004
Posts: 34030
Location: Hereford
PostPosted: Sat Apr 11, 15 8:30 am    Post subject: Reply with quote    

In response to the current Californian trend of actually eating kale, a Polish immigrant described it as 'after the war food'. I suspect it was a mainstay. If it gave problems, that would be a place to look.

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