Guest guest Posted August 30, 2003 Report Share Posted August 30, 2003 i was interested in chris' posts on this recently. i had found some studies that had found heat reduced oxalic acid content in some foods, but wasn't aware of the soil-nitrogen connection. here's another study that supports what chris wrote on this. does " ammonium salt " have anything to do with salinity? (i'm guessing " no " , right?) in any case, i just read a different study that mentioned increased salinity of soil reduced oxalate content of plants. http://www.nal.usda.gov/ttic/tektran/data/000007/88/0000078825.html EFFECT OF NITROGEN SOURCE AND RATE ON VEGETABLE AMARANTH LEAF BLADE MINERAL NUTRIENTS, PIGMENTS, AND OXALATES Author(s): MAKUS DONALD J HETTIARACHCHY N S Interpretive Summary: Vegetable amaranth is a warm-season green that is grown for local markets and also imported into the United States. Generally regarded as highly nutritious, like all greens, amaranths contain nitrates and oxalates, which in high amounts are regarded as anti-nutrients. The form that nitrogen exists as in fertilizer (N source) can effect plants in subtle ways. In this study, we found that when nitrate nitrogen was supplied, leaf blade soluble oxalates and nitrate levels were higher than when an ammonium salt was used as the nitrogen source in the fertilizer. Increasing the nitrogen rates applied to the soil from 0 to 200 lbs/Ac increased leaf protein, potassium, phosphorus, nitrates, iron, chlorophyll (greenness), total carotenoids (source of Vit. A), and total oxalates. Under the worst conditions observed in this study, both nitrate and soluble oxalate were at levels well within those considered safe for human consumption. ----------------------- oops! i see chris posted an abstract on the same study, albeit written by someone else and in more technical terms. it does seem from the info that chris posted that the best way to deal with oxalic acid is to " know your source " and buy heirloom breed plant foods whenever possible, although oxalic acid *can* also be reduced by heat. BUT, as chris mentioned, heat also destroys beneficial nutrients as well, so you lose something in the process. i'd love to know how much oxalic acid is reduced by fermentation...? Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- " The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times. " -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 In a message dated 8/30/03 4:52:41 PM Eastern Daylight Time, s.fisher22@... writes: > it does seem from the info that chris posted that the best way to deal with > oxalic acid is to " know your source " and buy heirloom breed plant foods > whenever possible, although oxalic acid *can* also be reduced by heat. BUT, > as chris mentioned, heat also destroys beneficial nutrients as well, so you > lose something in the process. Suze, as stated before, I believe heat has no effect whatsoever on oxalates. Do you have any evidence to the contrary? Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 In a message dated 8/30/03 4:52:41 PM Eastern Daylight Time, s.fisher22@... writes: > i'd love to know how much oxalic acid is reduced by fermentation...? Oh, I forgot to respond to this. I believe that it depends on the content of soluble versus insoluble oxalates. Insoluble oxalates are not affected by fermentation according to the limited evidence I've found, while soluble are. Wild mushrooms were found to be free of insoluble oxalates, while cultivated mushrooms were found to be higher in soluble oxalates as well as having high amounts of insoluble oxalates. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 >i'd love to know how much oxalic acid is reduced by fermentation...? Hmm ... actually it looks like oxalic acid can be PRODUCED by fermentation. See below. But the Koreans don't seem to be having bad results from it ... maybe they also get a dose of the oxalate-eating-bacteria. Also there seems to be an issue with oxalate vs. oxalic acid -- if the acid combines with calcium, the calcium oxalate isn't toxic (probably not very digestible either?) so if you ferment with a calcium source (seseme seeds/oysters/ground fish) then you would have oxalates, not oxalic acid. Hmm ... I'm having deja vu all over again ... And maybe cooking DOES do something to the oxalates: http://roberthamilton.pageout.net/user/www/r/o/roberthamilton/Roots.html Like other plants in this family, taro produces calcium oxalate crystals, that cause a burning and stinging in the throat. However cooking breaks down the calcium oxalate, releasing the calcium. Taro has been introduced throughout the world, being brought from Africa to the new world by slaves. Taro is cultivated throughout the tropics as it grows well in saturated soils. Taro is usually propagated by culturing the tops of the corms (cormels). http://pasteur.fontismedia.com/infiles/out/res030017.pdf Oxalic acid is a common metabolite excreted by several fungi under specific growth conditions. Accumulation of oxalate by fungi, particularly in Aspergillus, Penicillium and Mucor species, is substantial enough so that these fungi could be used for industrial production of oxalate. Aspergillus strains are the most potent producers of oxalic acid [59]. Among the bacteria, oxalate has been detected in cultures of Mycobacterium, Acetobacter, and Gluconabacter and in cell free extracts of Lactobacillus [22]. 50 http://www.korea.net/koreanculture/kimchi/kimchi_4.html During fermentation there is the biggest change in organic acid. The quantity of organic acid products in kimchi varies according to the enzymes in vegetables or enzymes secreted by various microorganisms during fermentation. It also varies according to the combination of ingredients and temperature during fermentation, duration of fermentation and salt concentration levels. When organic acids are analyzed at different salt concentration levels, non-volatile organic acids such as lactic acid, oxalic acid, malonic acid, succinic acid, malic acid, and citric acid are produced, regardless of the salt concentration. But there is a difference in quantity of acid production according to the salt concentration. At high salt concentration levels kimchi produces less lactic acid and succinic acid and more citric acid than at low salt concentration levels. At the beginning of kimchi fermentation, malic acid is mostly contained in cabbages, but in matured kimchi, lactic acid and succinic acid increase considerably. There is no difference in the citric acid concentration at high temperatures (22°C to 23°C) and at low temperatures (6°C to 7°C) during fermentation, but at a low temperature, lactic acid and succinic acid are reported to be high, while malic acid, oxalic acid, tartalic acid and malonic acid are reported to be low. Kimchi's organic acid also changes according to the duration of fermentation. When kimchi is fermented at a low temperature (5°C), small amounts of lactic acid and citric acid are produced at early stages and increase as time passes by, while large amounts of malic acid at early stages decrease as time goes by. Other acids such as oxalic acid, malonic acid and succinic acid do not change according to the duration of fermentation. Organic acid and carbon dioxide in kimchi are the two main elements which determine the taste of kimchi. The amount of organic acid and carbon dioxide varies according to the kind of microorganism, salt concentration and temperature, as has already been explained. Kimchi fermented at a low salt concentration and low temperature is found to have high acetic acid and carbon dioxide, and such a kimchi proves to be more tasty. -- Heidi Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 > it does seem from the info that chris posted that the best way to deal with > oxalic acid is to " know your source " and buy heirloom breed plant foods > whenever possible, although oxalic acid *can* also be reduced by heat. BUT, > as chris mentioned, heat also destroys beneficial nutrients as well, so you > lose something in the process. >>>Suze, as stated before, I believe heat has no effect whatsoever on oxalates. Do you have any evidence to the contrary? ----->i've read a number of abstracts and studies that reduced oxalates with heat. i posted one a month or so ago, and i looked for it in the archives yesterday, but couldn't find it. the search engine really *sucks*! or maybe it was oxalic acid that was reduced by heat...i don't recall. would that make more sense? Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- " The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times. " -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 wow, interesting about the *increased* oxalic acid in kimchi. i do wonder if it goes hand in hand with the oxalate eating bacteria? on the chapter leader list someone posted that they went to a seminar (on fermenting, i think) and the guy, who's somehow involved in agriculture and has written about fermenting and related stuff, IIRC) told them that oxalic acid is *reduced* by fermenting. i tried tracking down a reference, but never found one. Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- “The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times.” -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 In a message dated 8/31/03 2:06:48 AM Eastern Daylight Time, heidis@... writes: > Also there seems to be an > issue with oxalate vs. oxalic acid -- if the acid combines with > calcium, the calcium oxalate isn't toxic (probably not > very digestible either?) so if you ferment with a calcium > source (seseme seeds/oysters/ground fish) then you would > have oxalates, not oxalic acid. Hmm ... I'm having deja vu > all over again Heidi, No acid can combine with Ca or any other metal, only bases can. Oxalate combines with Ca to make calcium oxalate. I dont think either oxalic acid is toxic nor calcium oxalate, but rather oxalate is an antinutrient because it binds up the calcium. Oxalic acid is an antinutrient because it apparently has a higher affinity for Ca(2+) than H+, and it quickly turns to oxalate when its H+'s ionize. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 In a message dated 8/31/03 8:26:03 AM Eastern Daylight Time, s.fisher22@... writes: > ----->i've read a number of abstracts and studies that reduced oxalates > with > heat. i posted one a month or so ago, and i looked for it in the archives > yesterday, but couldn't find it. the search engine really > *sucks*! > > or maybe it was oxalic acid that was reduced by heat...i don't recall. would > that make more sense? Suze, What was the method of heating? I posted abstracts showing that heating did nothing to oxalates whatsoever except in the form of steaming and boiling, where all oxalate reduction was accounted for by runoff of the oxalates into the water. Oxalic acid is oxalate with H+. As far as I know, plants produce oxalates, not oxalic acid, though oxalate and oxalic acid could be easily transformed back and forth into each other by the ionization of H+ or the reassociation of H+. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 31, 2003 Report Share Posted August 31, 2003 In a message dated 8/31/03 5:22:07 PM Eastern Daylight Time, s.fisher22@... writes: > wow, interesting about the *increased* oxalic acid in kimchi. i do wonder > if > it goes hand in hand with the oxalate eating bacteria? on the chapter leader > list someone posted that they went to a seminar (on fermenting, i think) and > the guy, who's somehow involved in agriculture and has written about > fermenting and related stuff, IIRC) told them that oxalic acid is *reduced* > by fermenting. i tried tracking down a reference, but never found one. I don't think it goes hand in hand in the sense that if there are oxalate-eating bacteria they should reduce the oxalate, not produce oxalate. Apparently there are bacteria which reduce oxalates and there are bacteria which produce oxalates, which means that fermentation is total luck unless you've investigated it enough where you are sure you are using a starter culture that will reduce the oxalates. Rumen contains oxalate-reducing bacteria. But again, insoluble oxalates cannot be reduced by bacteria according to one study I posted, and certainly cannot be reduced by cooking, which as far as I can tell does not do anything to destroy oxalates but only makes oxalate runoff in the water. I should have pointed this out in my response to Heidi-- the dissociation of Ca from oxalate is not the destruction of an oxalate. Ca salts have varying partial solublility, and the heating of *anything* in water that is partially soluble will increase the solubility. While Ca oxalate might be irritating to some people, the main reason oxalates are proscribed against is because they can bind Ca. Consuming an oxalate is consuming an oxalate, period, which can bind Ca in your system. Moreover, the heated Ca oxalate which dissociated would almost definitely reassociate into Ca oxalate over time once the temperature of the solution was dropped to the temp it started at. So as far as I can tell, heat does nothing to destroy oxalates, steaming or boiling will reduce them along with all of the water-soluble nutrients in the food you are steaming and boiling (only you will lose more nutrients than oxalates probably due to the high insoluble oxalate content of many foods), and fermenting is a mixed bag and probably is not a good way to reduce oxalates. It looks like the only good shot is to get food that has been grown and fertilized properly and has not been genetically emasculated, and to stay away from the high-oxalate foods if you have a high need for Ca and other minerals. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 >told them that oxalic acid is *reduced* >by fermenting. i tried tracking down a reference, but never found one. I'm thinking the difference may be in oxalate vs. oxalic acid. The two terms get used interchangably, but I read where someone was concerned because rhubarb contains " not only oxalates, but also oxalic acid, which is toxic " . Now oxalates are usually calcium oxalate, which is non-soluable, and I'm not sure it ever gets digested ... the point with spinach is that it binds to calcium and so you don't get the calcium because the calcium oxalate is excreted. The Koreans put a lot of calcium-containing stuff in their kimchi, so maybe some of that calcium goes to make calcium oxalate, which isn't toxic? And probably not used either, unless you have the correct bacteria. But they probably DO have the right bacteria, because most humans do ... unless they've been on antibiotics. The oxalate eating bacteria are common enough and most babies pick them up from the environment. Which makes me think they should exist in kimchi too ... but then why would kimchi have high oxalate levels? So many questions ... -- Heidi Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 Suze, Why would heirloom grains be less of a problem in terms of oxalates? If I understand what has been posting that would be a function of the soil, not necessarily the type of grain. And that certainly seems to be what Albrecht, Reams and others are saying. I'm sorry I no longer have the post where you mentioned that, so I hope you remember. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 >>>>Why would heirloom grains be less of a problem in terms of oxalates? If I understand what has been posting that would be a function of the soil, not necessarily the type of grain. ----->oh, the heck if i know! LOL. i thought that was part of the info chris posted...that modern breeds were higher in oxalates, but i could've remembered what he posted incorrrectly. oh wait! that ginko really *is* working...i had saved that post because i was fascinated by it. here's what chris wrote about this: " Interestingly, the mushroom study found cultivated breeds of mushrooms to be quite a bit higher in oxalates than wild breeds, and what's more, they contained only soluble oxalates and no insoluble oxalates. Soluble oxalates are more easily broken down. I don't know whether or not that can be said for crops in general-- that more modern breeds have higher oxalate contents-- but if that can be extrapolated, there's one more reason to throw on to the pile of why to eat heirloom/wild breeds. " after that he discussed soil quality. Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- " The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times. " -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 > ----->i've read a number of abstracts and studies that reduced oxalates > with > heat. i posted one a month or so ago, and i looked for it in the archives > yesterday, but couldn't find it. the search engine really > *sucks*! > > or maybe it was oxalic acid that was reduced by heat...i don't recall. would > that make more sense? >>>>What was the method of heating? I posted abstracts showing that heating did nothing to oxalates whatsoever except in the form of steaming and boiling, where all oxalate reduction was accounted for by runoff of the oxalates into the water. ----->i *think* they tried different methods of heating to compare reduction rates, but i don't recall exactly. i'm quite certain boiling was at least one method used. Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- " The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times. " -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- Re: oxalates In a message dated 8/31/03 8:26:03 AM Eastern Daylight Time, s.fisher22@... writes: Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 >>>>No acid can combine with Ca or any other metal, only bases can. Oxalate combines with Ca to make calcium oxalate. I dont think either oxalic acid is toxic nor calcium oxalate, but rather oxalate is an antinutrient because it binds up the calcium. ----->well the other problem with ca oxalate is that stones formed from ca oxalate can block normal bladder function, right? i mean, these are what's referred to as " bladder stones " right? i have an e-pal whose dog has this condition and was going to be operated on, until she tried a natural remedy that seemed to dissolve the stones last i heard. Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- " The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times. " -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- Re: oxalates In a message dated 8/31/03 2:06:48 AM Eastern Daylight Time, heidis@... writes: > Also there seems to be an > issue with oxalate vs. oxalic acid -- if the acid combines with > calcium, the calcium oxalate isn't toxic (probably not > very digestible either?) so if you ferment with a calcium > source (seseme seeds/oysters/ground fish) then you would > have oxalates, not oxalic acid. Hmm ... I'm having deja vu > all over again Heidi, No acid can combine with Ca or any other metal, only bases can. Oxalate combines with Ca to make calcium oxalate. I dont think either oxalic acid is toxic nor calcium oxalate, but rather oxalate is an antinutrient because it binds up the calcium. Oxalic acid is an antinutrient because it apparently has a higher affinity for Ca(2+) than H+, and it quickly turns to oxalate when its H+'s ionize. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 >Heidi, > >No acid can combine with Ca or any other metal, only bases can. I think I meant just what you say below ... the " oxa-- " part of the ion combines with Ca++ to make oxalate. But if it is in ionic form (dissolved) it is oxalic acid ( " oxa-- " plus 2H+, dissolved). If it combines with Ca it becomes less soluable, so perhaps less toxic, or so some people seem to think. My question would be, how toxic is it, really? Given that it seems to be so darn common, you'd think we should be able to handle it. Oxalic acid IS toxic, not just because it is an antinutrient, in larger doses, I guess because it binds up Ca in the body to the degree it can kill you. People die from eating rhubarb leaves ... -- Heidi > Oxalate >combines with Ca to make calcium oxalate. I dont think either oxalic acid is >toxic nor calcium oxalate, but rather oxalate is an antinutrient because it binds >up the calcium. Oxalic acid is an antinutrient because it apparently has a >higher affinity for Ca(2+) than H+, and it quickly turns to oxalate when its >H+'s ionize. > >Chris > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 In a message dated 8/31/03 11:25:32 PM Eastern Daylight Time, slethnobotanist@... writes: > Why would heirloom grains be less of a problem in terms of oxalates? If > I understand what has been posting that would be a function of the > soil, not necessarily the type of grain. I don't know about grains, but wild mushroom breeds were found to have low soluble oxalates and NO insoluble oxalates, and cultivated mushrooms were found to be high in both, in one abstract I posted. An extrapolation could be that this MIGHT apply across the board to wild vs cultivated breeds, but obviously does not necessarily apply that broadly. According to Diamond in Guns, Germs and Steel, domestication has had a dramatic impact on increasing sprout inhibitors, so perhaps there is some logic to it increasing other antinutrients, though I don't know what it is, as I haven't quite figured out what the function of oxalates are to the plants themselves. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 1, 2003 Report Share Posted September 1, 2003 In a message dated 9/1/03 2:43:46 AM Eastern Daylight Time, s.fisher22@... writes: > ----->well the other problem with ca oxalate is that stones formed from ca > oxalate can block normal bladder function, right? i mean, these are what's > referred to as " bladder stones " right? i have an e-pal whose dog has this > condition and was going to be operated on, until she tried a natural remedy > that seemed to dissolve the stones last i heard. Suze, I don't know anything about it but don't have any reason to disbelieve it. But the main reason oxalates are usually proscribed against is their antinutrient capacity. That's why Walcott mentions them (protein types have high needs for Ca and must strictly avoid oxalates and phytates), that's why Prescription for Nutritional Healing discusses them, there are abstracts out there that discuss them and are overwhelmingly concerned with their antinutrient capacity, at least in the one's I've read. I really don't see why it matters in terms of oxalic acid versus oxalates, as oxalic acid that binds up Ca in your system, is going to simultaneously prevent you from using the Ca and contribute to Ca oxalate intake and therefore bladder stones. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 3, 2003 Report Share Posted September 3, 2003 On Mon, 1 Sep 2003 00:02:45 -0400 " Suze Fisher " <s.fisher22@...> wrote: > >>>>Why would heirloom grains be less of a problem in terms of oxalates? If > I understand what has been posting that would be a function of the > soil, not necessarily the type of grain. > > ----->oh, the heck if i know! LOL. i thought that was part of the info chris > posted...that modern breeds were higher in oxalates, but i could've > remembered what he posted incorrrectly. oh wait! that ginko really *is* > working...i had saved that post because i was fascinated by it. here's what > chris wrote about this: > > " Interestingly, the mushroom study found cultivated breeds of mushrooms to > be > quite a bit higher in oxalates than wild breeds, and what's more, they > contained only soluble oxalates and no insoluble oxalates. Soluble oxalates > are more > easily broken down. > This sounds to me like it is a function of the soil, not the breed, the wild breeds being in better soil. Put them in poor soil and you would have the same problems, heirloom or otherwise. excerpt doesn't say that but that would be in keeping with what I know about soil fertility. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 11, 2004 Report Share Posted October 11, 2004 In a message dated 10/11/04 6:15:17 PM Eastern Daylight Time, s.fisher22@... writes: The first one demonstrates that, at least in the African yam bean, that heat treatment does indeed reduce the oxalate content and NOT BY LEACHING in the case of auto-claving. _____ ~~~~~>My dictionary says autoclaves by definition use high-pressure steam for sterilization. Unless you have some reason to think they meant something else by " autoclave, " then I don't see your point. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 11, 2004 Report Share Posted October 11, 2004 In a message dated 10/11/04 6:46:42 PM Eastern Daylight Time, s.fisher22@... writes: But if oxalates are only reduced by leaching, where would they go, if leached in an autoclave? Wouldn't the researchers have noticed if there was any significant residue in the bottom of the autoclave? ____ ~~~~~> I'm not sure why it matters, since the steam has to go *somewhere*. Presumably, the oxalates go wherever the steam goes. I have no idea what the volatility of oxalate is, or how the high pressure in an autoclave affects it, but if the oxalates are attracted to the steam enough to be drawn out of the plant, then they could certainly be carried to wherever the water is kept in the autoclave. Besides, the researchers doing your study, unlike the researchers in the study I had posted on NN last year, weren't interested in the effect of heat per se as distinguished from leaching. If they were, they would have had a control that did not use water, they would have checked the water for oxalate content, and they would have at least mentioned the issue in the abstract. ______ It's also interesting that the point of the study wa to determine how *heat* treatment affected oxalates, not leaching. _____ ~~~~> Then that just shows the incompetence of the researchers, who failed to engage in the seemingly obvious activities that would control for leaching, such as a control using non-water heating, and checking the water for oxalate content. _____ And the authors of the study claimed that it was the *heat* that reduced the oxalates. Not that they couldn't be wrong, but I don't feel like paying for the full study, which may, or may not give enough details to determine this. _____ ~~~~~> We can pretty well assume that they are wrong, since the study I posted checked the steaming and boiling water for oxalate content and found that essentially the *entire* oxalate reduction in the food was accounted for in the water. They furthermore differentiated between soluble and insoluble oxalates, and found that there was a significant reduction in soluble oxalates and NO reduction in insoluble oxalates. And this was all in the abstract, by the way. So I think the care used in that study clearly trumps the careless methodology of the study you posted. And the conclusion of a study is always the stupidest part of it, so I would NEVER trust that a researcher's conclusion is even logical. ________ In any case, it's clear that steaming or boiling reduces oxalates *signifcantly*. _____ ~~~~> I agree that it does, but I disagree that this is attributable to heat. _____ Personally, I almost always steam my high oxalate veggies. As for high oxalate grains, they are typically eaten soaked (historically) and/or boiled (historically and currently), so that should help reduce the oxalates. ______ ~~~~~> I don't think soaking would affect the oxalate content unless the water is thrown out. With boiling, the water is usually thrown out, so that would be helpful. But the water will contain all of the soluble oxalates, so consuming it would be no different than consuming the unprocessed grain. Chris Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 11, 2004 Report Share Posted October 11, 2004 > Re: OXALATES > > > >In a message dated 10/11/04 6:15:17 PM Eastern Daylight Time, >s.fisher22@... writes: >The first one demonstrates that, at least in the African yam bean, >that heat >treatment does indeed reduce the oxalate content and NOT BY LEACHING in the >case of auto-claving. >_____ > >~~~~~>My dictionary says autoclaves by definition use >high-pressure steam for >sterilization. Unless you have some reason to think they meant something >else by " autoclave, " then I don't see your point. > >Chris I used to have an autoclave when my ex and I owned a tattoo studio. We autoclaved the equipment often. My recollection is that there was no mechanism for trapping residue that might be leached by whatever was autoclaved. Autoclaves are designed to sterilize *dental* equipment, to my knowledge. It's possible that there are different kinds of autoclaves, I don't know. But if oxalates are only reduced by leaching, where would they go, if leached in an autoclave? Wouldn't the researchers have noticed if there was any significant residue in the bottom of the autoclave? It's also interesting that the point of the study wa to determine how *heat* treatment affected oxalates, not leaching. And the authors of the study claimed that it was the *heat* that reduced the oxalates. Not that they couldn't be wrong, but I don't feel like paying for the full study, which may, or may not give enough details to determine this. In any case, it's clear that steaming or boiling reduces oxalates *signifcantly*. Personally, I almost always steam my high oxalate veggies. As for high oxalate grains, they are typically eaten soaked (historically) and/or boiled (historically and currently), so that should help reduce the oxalates. Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- " The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times. " -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 12, 2004 Report Share Posted October 12, 2004 > Re: OXALATES > > > >In a message dated 10/11/04 6:46:42 PM Eastern Daylight Time, >s.fisher22@... writes: > But if oxalates are only reduced by leaching, where would they >go, if leached in an autoclave? Wouldn't the researchers have noticed if >there was any significant residue in the bottom of the autoclave? >____ > >~~~~~> I'm not sure why it matters, since the steam has to go >*somewhere*. >Presumably, the oxalates go wherever the steam goes. I thought the steam *evaporates*? I have no >idea what the >volatility of oxalate is, or how the high pressure in an autoclave >affects it, >but if the oxalates are attracted to the steam enough to be drawn >out of the >plant, then they could certainly be carried to wherever the water >is kept in >the autoclave. IF they are only *removed* from the bean flour (or other plant material) and not destroyed or reduced by the heat while still IN the flour (like goitrogens, trypsin inhibitors or heat-labile vitamins). Perhaps they are reduced by both leaching AND heat? I just googled " heat labile oxalic acid " and couldn't find anything though. I know other acids are indeed heat-labile like ascorbic acid. But maybe *oxalic* acid isn't. It is interesting though that *drying* may reduce it too, which involves no leaching into water or steam. I wonder *what* causes the reduction then when no water or steam is involved? > >Besides, the researchers doing your study, unlike the researchers in the >study I had posted on NN last year, weren't interested in the >effect of heat per >se as distinguished from leaching. If they were, they would have >had a control >that did not use water, they would have checked the water for oxalate >content, and they would have at least mentioned the issue in the abstract. I agree that they needed to have a dry heat control in order to determine it was the heat and not leaching (exclusively) that reduced the oxalates so drastically. However, they do mention that the moisture content increased slightly *after* the treatment. It seems to me if something were being leached *from* a food into water or steam, then the moisture content of the food would *decrease* not *increase* after being cooked or autoclaved. One interesting side not here, notice that the trypsin inhibitors were the most heat-labile. I wonder how much of the trypsin inhibitors are reduced in legumes, nuts, etc when they are cooked on medium or low heat *without* pre-soaking as so many *non*-traditional peoples do? Maybe the auto-claving at the temp and pressure that these researchers used served as a sort of " pre-soak " , or maybe not. But it's interesting to see how heat affects trypsin-inhibitors. Maybe we don't always need to pre-soak foods with trypsin inhibitors in order to reduce them significantly? >______ >It's also >interesting that the point of the study wa to determine how *heat* >treatment >affected oxalates, not leaching. >_____ > >~~~~> Then that just shows the incompetence of the researchers, >who failed to >engage in the seemingly obvious activities that would control for >leaching, >such as a control using non-water heating, and checking the water >for oxalate >content. I agree 100%. >_____ >And the authors of the study claimed that >it was the *heat* that reduced the oxalates. Not that they couldn't be >wrong, but I don't feel like paying for the full study, which may, or may >not give enough details to determine this. >_____ > >~~~~~> We can pretty well assume that they are wrong, since the study I >posted checked the steaming and boiling water for oxalate content >and found that >essentially the *entire* oxalate reduction in the food was >accounted for in the >water. They furthermore differentiated between soluble and insoluble >oxalates, and found that there was a significant reduction in >soluble oxalates and NO >reduction in insoluble oxalates. And this was all in the abstract, by the >way. I don't remember it. Do you still have it? I'd like to see it, if so. So I think the care used in that study clearly trumps the careless >methodology of the study you posted. And the conclusion of a >study is always the >stupidest part of it, so I would NEVER trust that a researcher's >conclusion is >even logical. I agree. That's why I said (in so many words) they could be wrong in their conclusion and we'd need the full study to determine if they were or not. > Personally, I almost always steam my high oxalate veggies. >As for high oxalate grains, they are typically eaten soaked (historically) >and/or boiled (historically and currently), so that should help reduce the >oxalates. >______ > >~~~~~> I don't think soaking would affect the oxalate content unless the >water is thrown out. You are *supposed to* throw out the water :-) That goes for anything you soak - legumes, rice, nuts etc, for the very reason that several anti-nutrients are leached out into the water. With boiling, the water is usually thrown >out, so that would >be helpful. But the water will contain all of the soluble oxalates, so >consuming it would be no different than consuming the unprocessed grain. I don't think we can conclude based on that *one* study on one particular food item (or was it multiple varieties of foods?) that ALL insoluble oxalates remain intact in all foods regardless of soaking and regardless of time and temp cooked. Suze Fisher Lapdog Design, Inc. Web Design & Development http://members.bellatlantic.net/~vze3shjg Weston A. Price Foundation Chapter Leader, Mid Coast Maine http://www.westonaprice.org ---------------------------- " The diet-heart idea (the idea that saturated fats and cholesterol cause heart disease) is the greatest scientific deception of our times. " -- Mann, MD, former Professor of Medicine and Biochemistry at Vanderbilt University, Tennessee; heart disease researcher. The International Network of Cholesterol Skeptics <http://www.thincs.org> ---------------------------- > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 13, 2004 Report Share Posted October 13, 2004 >As for Heidi's contention that oxalates in food are only a problem for those >on antibiotics, I'd like to see some evidence of that before believing it. >There is no mention of antibiotics in some of the abstracts below in which >oxalates were found to be problematic for humans and animals. Heidi, do you >have any info on the studies that led you to believe there's a link to >antibiotic treatment? Well, first of all, I'd agree that some foods are so high in oxalates that they really are a problem for anyone. Most of those kinds of foods aren't commonly eaten in the US, or the oxalates have been bred out of them. As for the link about antibiotics, I think you listed it: The grant will enable UF College of Medicine pathologist Ammon Peck and colleagues to determine whether kidney stones can be prevented in laboratory rats by giving them a coated pill to replenish a beneficial bacteria called Oxalobacter formigenes. An absence of this intestinal bacteria has been linked to the development of calcium oxalate kidney stones. (full article at above link). The link between oxalobacter and kidney stones was first noted in humans ... folks who had bladder infections were more likely to get kidney stones, and the connection seems to be that a person with bladder infections gets antibiotics. But here is a good writup: http://www.pslgroup.com/dg/b154a.htm " Our study in fact shows that cystic fibrosis patients, in general, have a very, very low frequency of colonisation with this intestinal bacteria, " said Ammon Peck, a professor of pathology at UF's College of Medicine. Of the 43 cystic fibrosis patients UF researchers studied, 19 produced too much oxalate and all 19 lacked the bacterium, Peck said. In contrast, the few patients who were colonised -- even with low levels of the organism -- had normal oxalate levels. The study participants, all residing in Germany and ranging in age from three to 39, had cystic fibrosis and showed no signs of an intestinal malabsorption problem. Their results were compared with findings from 21 healthy volunteers ages four to 44. O. formigenes appears to break down calcium oxalate before it can form crystals that evolve into kidney stones, he said. Oxalate is found in high concentrations in many foods, including asparagus, tea, broccoli, peanut butter, spinach and chocolate. When oxalate levels are kept low, it is easier for the body to excrete the substance through the kidneys. But if there is more oxalate than can be dissolved in the urine, the crystals settle out and form stones. Peck and colleagues suspect prolonged antibiotic use and other high-dose drug regimens may preclude natural colonisation with the organism, or may irreversibly destroy the colonies. Most infants naturally acquire the bacterium from their environment between the ages of nine months to one year and by six to eight years of age almost all healthy children are colonised. Researchers reviewed study participants' medical records and discovered that among the patients, 29 different antibiotic regimens had been used and many patients were likely to be on other medications as well. Only one patient had not been treated with antibiotics -- the only person who tested strongly positive for O. formigenes. So MOST people do have O. formigenes, and people with that bacteria have normal oxalate levels. As for vegetables being healthy ... just about every dietary study I've ever read mentions that vegies prevent this or that: http://www.hsph.harvard.edu/nutritionsource/fruits.html Given that vegies tend to have oxalates, I'd argue that the oxalates in vegies don't seem to *prevent* good health. Of course, fermented vegies might even give BETTER health, and I actually eat many of mine fermented. I don't notice any bad results from eating them raw though, even raw rhubarb, and my body is pretty picky. >Again, my feeling is that we are eating foods in a manner that was not done >by our species traditionally and just expecting to be OK with it. Just >because it's popular to eat raw high oxalate foods in our brief historical >moment of time doesn't mean it's healthy. My understanding is that early >Americans never ate raw or unfermented veggies. I could be wrong, but it's >also my understanding that raw green salads are a modern invention. I also >suspect that our soil depletion over the past 50 years or so is likely >contributing to the high level of oxalates in many varieties of veggies. >It's not *God* doing something wrong, IMHO - it's *us*. I disagree here ... greens are one food that are easy to find year round, and most cultures do eat them (even raw). They also ate stuff like the area under spruce bark. But Miner's lettuce and corn salad were commonly eaten by the pioneers (and the Indians). Greens are eaten by primates too. Tubers are another food that have been eaten for a long time ... the Indian squaws dug up arrowroot tubers (which are much like potatoes) with their toes in the swamps, and another tuber called " Squaw root " . The reliance on *grains* is a new development, and really changed how people live. A good documentary on this is " Guns, Germs, and Steel, " which isn't about nutrition but is about how farming changed society, and allowed cultures with stored grain and horses and cattle to conquer other cultures who didn't have these. Heidi Jean Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 13, 2004 Report Share Posted October 13, 2004 >. It is interesting though >that *drying* may reduce it too, which involves no leaching into water or >steam. I wonder *what* causes the reduction then when no water or steam is >involved? One of the main criticisms of oxalates is that they bind to minerals so the minerals don't get used. Maybe drying etc. causes the oxalate to bind to something or to be transformed a bit. Oxalate is C2O4 and there seem to be reactions where it is transformed into CO2 ... so if high heat or sunlight or whatever triggers one of those reactions you could get rid of the oxalate without it leaching into water. Heidi Jean Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 16, 2004 Report Share Posted October 16, 2004 In a message dated 10/13/04 9:44:09 AM Eastern Daylight Time, s.fisher22@... writes: Ah yes, you are right. I meant that it dissipates... disappears. I don't know where to. It's been a long time since I saw an autoclave in action. _____ ~~~~~> Well, it can't disappear. Either it gets recycled and reenters w hatever is holding the source water, it condenses on the walls of the autoclave, or it exits the autoclave and enters the air surrounding the autoclave. But it can't " disappear. " If the oxalates can travel in the steam to come out of the vegetables, I wouldn't necessarily *assume* that they couldn't travel further in the steam. And if not, then presumably they'd be accumulating in the autoclave... in any case, when vegetables are steamed and boiled, the oxalates end up in the source water, having travelled there with the steam. _____ What vegetables did they cook? ____ ~~~~> I don't remember. But I did make a mistake in saying that antitrypsin is a glycoprotein. Maybe it isn't one, I don't know, but I was thinking of avadin, the compound that binds biotin. I don't know what antitrypsin is, chemically. _____ You may be right, although I'm still curious about the Andean Indians reducing oxalates simply by drying yams in the *sun*. So far, most or all of the pubmed abstracts I've looked at discuss it being leached out into water (except the one mentioned above, in which the oxalates DID leach into the water, but it was attributed to the heat). Of course they're not interested in ancient or traditional food preparation, so it's not likely they'd be testing oxalate content after sun drying. LOL ____ ~~~~> I'm not sure what research you're talking about that found that Andeans reduced oxalates by drying. In any case, sun-drying doesn't create a very large amount of heat... ____ Possibly. But this brings up an interesting point. Remember that the USDA data is VERY unreliable when it comes to determining nutrient values in foods for several reasons. Chief among them is that the nutrient content of a crop grown in one field as opposed to another can vary as high as several hundred percent! Even those grown across the street from each other can vary significantly in their nutrient content. So unless they were testing a boiled and baked potato grown very close together in the same field, the numbers should be taken with a grain of salt when compared to one another. Secondly, and my first point makes this moot for the most part, what was their sample size? Sometimes, it's just a few specimens. Basing conclusions on just a few data points is not very useful. _____ ~~~~~>Ok, I agree their data might be unreliable, but in the absence of more reliable data, I don't see what else to use. Moreover, since it doesn't make much sense to me that ascorbic acid would be very heat-labile, I would assume it isn't until I see evidence of dry heat causing significant ascorbic acid loss. I'm not saying there isn't any... but I haven't seen it; do you have any on hand? Have you seen any? _____ Regarding comparing the vit C content of vegetables - here is something interesting. I just compared the vit. C content of RAW sweet potato and baked sweet potato (skin on). Both used only 4 test samples. The raw sweet potato had 2.4 mgs vitamin C per 100 grams edible portion and the baked sweet potato had 19.6 mgs per the same portion! How do you suppose *baking* a sweet potato could increase the vitamin C content 8 TIMES?? ____ ~~~~> Quite simply: the moisture loss in baking concentrates the sweet potato, so that water is not occupying mass, and all components of the vegetable increase in concentration when measured as a ratio of amount to mass of the total vegetable. _____ I have two guesses. One - these sweet potatoes were grown in different soils and their nutrient content reflects that. Two, the ascorbic acid in the *raw* sweet potato is bound to something...maybe calcium? And the heat (dry heat in this case) unbinds them, thus increasing the ascorbic acid content (although it could possibly be simultaneously destroying *some* of the ascorbic acid content, as well). _____ ~~~~~~> Those are " valiant explanations " as my chemistry professor once credited me for when I did a lot of thinking to come up with clever explanations rather than simple and more obvious explanations, but it is much more simple to assume that cooking is reducing the moisture content, since the vitamins between raw and cooked are consistently higher in cooked, for that reason. Good thoughts, but probably not necessary. ____ As for " regular " potatoes, here are the ascorbic acid amounts listed on the USDA database per 100 grams: raw: 19.7 mgs boiled (w/skin): 5.2 mgs baked (w/skin): 13.5 mgs How do we interpret these data? First, the raw potato was listed as a " red " potato and the other two weren't. So that muddies the already muddy waters. The trend among these potatoes of unknown origins *seems* to be that baking reduces *some* of the ascorbic acid (although it had the *opposite* effect in the *sweet* potatoes *assuming* [probably erroneously] that the sweet potatoes had an equivalent amount of ascorbic acid to begin with) and boiling seems to reduce it even more. However as I mentioned before, I hesitate to draw any conclusions based on 3 data points of potatoes that might have had extreme nutrient level differences in their virgin state from the others I'm comparing them to. ____ ~~~~> I agree. Were we comparing the same foods, it would appear that vitamin C is quite heat-labile but is lost in greater amounts due to leaching when boiled. But since the red and regular potatoes may well vary in vitamin C content, it's pretty impossible to draw any conclusions. ____ In any case, it's fun to play games with USDA data, but it's probably fairly useless to base any conclusions by comparing a few data points from vegetables that might have started out with drastically different nutrient values than each other in the raw state. ____ No, *Deb* posted about it. She said that when she was researching yams, she'd read that the Andean Indians' traditional method of reducing oxalate content in their " oca " (yams) was to leave them out in the sun for several days before eating them either raw or cooked. That's actually the first time I've heard of potatoes eaten *raw* by an ancient culture. Perhaps she has a URL or source where we can look into that interesting tidbit further... _____ ~~~~> Who came up with the oxalate explanation for the drying? The Andeans? Did anyone study the oxalate content? I'll try to look for the post in the pile of unread email lying in my box. ____ Also, in your response you didn't address my comments below. Do you have any comment? >I don't think we can conclude based on that *one* study on one particular >food item (or was it multiple varieties of foods?) that ALL insoluble >oxalates remain intact in all foods regardless of soaking and regardless of >time and temp cooked. ____ ~~~~> I don't think the number of studies matters except in that replications with comparable methods yielding different results would cast doubt on the competency or honesty of the researchers, and, conversely, agreeable studies would further our confidence in the honesty and competency of the researchers. But since the study I mentioned (which did use a variety of foods, but I don't remember which ones or how many) showed in several different ways that the oxalate loss is due to leaching into water, simple logic would dictate that only soluble oxalates would be lost. Since this simple matter of logic agrees with their results, there is, as yet, no reason to doubt that. Chris Quote Link to comment Share on other sites More sharing options...
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