Guest guest Posted October 11, 2004 Report Share Posted October 11, 2004 Ok, I've accumulated several studies or abstracts over the years on this issue. Here they are. 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. And in this case, by 49%! When cooked in water, the reduction increased to 72.2%. When I posted about this before, I didn't have the abstract handy, but happened to dig it up from another list I posted it to last year. I highlighted the pertinent part with " **** " . The second study also found a reduction in oxalates with heat treatment. Unfortunately, the link is now broken. 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? 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*. ---------------------------- http://tinyurl.com/4m6p9 Effect of heat treatment on the proximate composition, energy values, and levels of some toxicants in African yam bean (Sphenostylis stenocarpa) seed varieties. Onyeike EN, Omubo-Dede TT. Department of Biochemistry Nutrition and Toxicology Unit, Faculty of Science, University of Port Harcourt, PMB 5323, Port Harcourt, Nigeria. The effects of heat treatments on the proximate composition, energy content, and levels of some antinutritional factors in brown and marble-colored African yam bean (AYB) seed flours were investigated. In raw brown and marble-colored AYB seed flours; moisture content, dry matter, crude protein, crude fat, ash, total carbohydrate and caloric value did not differ significantly at the 5% level. Autoclaving and cooking slightly increased the moisture level. Crude protein, crude fat, and ash contents were decreased by autoclaving and were further decreased by cooking. The decrease was not, however, considerable for the AYB that is not eaten raw and whose full nutritional potential as a legume can be derived only when heat treated, as previous reports have indicated for legume seeds. ****The levels of the toxicants were generally higher in the raw brown AYB compared to the marble-colored, and were generally reduced by both autoclaving and cooking. In the most commonly available and consumed marble-colored AYB, autoclaving at 121 degrees C, 15 psi for 20 min decreased cyanogenic glycosides by 46%, oxalate by 48.9%, ****tannin by 15.0%, saponin by 14.8% and trypsin inhibitors by 61.3% while cooking for 3.5 hours in tap water decreased these toxic factors by 66.5%, 70.3%, 72.2%, 48.7%, and 86.0%, respectively. The results indicate that for raw samples, varietal difference did not significantly affect nutrient composition though the toxicants were generally higher in the brown AYB than the marble-colored. Autoclaving decreased both nutrient value and the level of toxicants in the two seed types; values were further reduced by cooking. Of the toxicants, trypsin inhibitor was found to be the most heat-labile and of the heat treatment methods, cooking to tenderness is recommendable. ---------------------------- http://147.46.94.112/e_journals/pdf_full/journal_p/p12_9953308.pdf Removal of antinutrients like oxalic acid and phytic acid during the blanching and cooking of these leaves might have asserted a beneficial effect on extractability of calcium and zinc, as antinutrients are known to have a hindering effect on mineral bioavailability [30]. ---------------------------- http://www.sciencedaily.com/releases/1998/03/980327091009.htm University Of Florida Researchers Test New Approach To Kidney Stone Prevention GAINESVILLE, Fla.---Aided by a new $1 million grant from the National Institutes of Health, researchers at the University of Florida are evaluating the feasibility of using a pill to prevent common calcium oxalate kidney stones. 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). -------------------------------- http://www.nal.usda.gov/ttic/tektran/data/000008/44/0000084447.html EVALUATING CHILDREN IN THE UKRAINE FOR COLONIZATION WITH THE INTESTINAL BACTERIUM OXALOBACTER FORMIGENES, USING A POLYMERASE CHAIN REACTION-BASED DETECTION SYSTEM Author(s): Interpretive Summary: Oxalic acid (and its salts - oxalates) are widely distributed in diets of man and animals. Dietary oxalates (as well as oxalate produced by tissue metabolism) are potentially toxic because elevated concentrations of oxalate in the urine increase the risk for formation of kidney stones composed of calcium oxalate. Oxalobacter formigenes, a bacterium that degrades oxalate, lives in the intestinal tract of animals and in some, but not all, humans. Oxalate degradation by this bacterium can reduce the amount of oxalate that is absorbed and thus reduce the risk for urinary stone disease. This paper describes new methods to detect O. formigenes. The methods developed use polymerase chain reaction (PCR) based amplification and then detection of DNA fragments that are uniquely present in O. formigenes. The detection system is more rapid than the cultural identification systems preivously used. The new system was compared with the cultural system in a field test using 100 fecal samples from children in the Ukraine (aged 0-12 yr). Data collected indicate that most infants less than 1 yr old were not colonized by O. formigenes but that all of the children became colonized by the age of 6-8 yr. The incidence of colonization then decreased in children who were 9-12 yr of age. These results provide the first insight into the time sequence of colonization of humans by O. formigenes and further support the concept that these bacteria are widely distributed in humans. The new methods that are described will facilitate extensive surveys in man and animals and will provide a basis for possible manipulations of the bacteria to provide protection from kidney stones and other diseases caused by oxalate. --------------------- http://www.nal.usda.gov/ttic/tektran/data/000007/98/0000079894.html DNA SEQUENCING AND EXPRESSION OF THE FORMYL COENZYME A TRANSFERASE GENE, FRC, FROM OXALOBACTER FORMIGENES Interpretive Summary: Kidney stones caused by calcium oxalate are a continuing health problem to farm animals and humans. The enzymes we found in Oxalobacter formigenes degrade oxalate and make it nontoxic. In this study, the sequence of the gene for formyl-CoA transferase was determined and its location on the bacterial chromosome was found. This should lead to the cloning of this gene into other bacteria found in the digestive tract of man and farm animals, and ultimately to the alleviation of the problem of kidney stones by oxalate. This would alleviate the pain, suffering, and the expense associated with treating and removing kidney stones. This information would be used by both the medical and veterinary profession. ---------------------- http://tinyurl.com/5hfzb Oxalate content of foods and its effect on humans SC Noonan BSc, MSc and GP Savage BSc(Hons), PhD, NZ Reg Nutr. Food Group, Division of Animal and Food Sciences, Lincoln University, Canterbury, New Zealand Oxalic acid and its salts occur as end products of metabolism in a number of plant tissues. When these plants are eaten they may have an adverse effect because oxalates bind calcium and other minerals. While oxalic acid is a normal end product of mammalian metabolism, the consumption of additional oxalic acid may cause stone formation in the urinary tract when the acid is excreted in the urine. Soaking and cooking of foodstuffs high in oxalate will reduce the oxalate content by leaching. The mean daily intake of oxalate in English diets has been calculated to be 70-150 mg, with tea appearing to contribute the greatest proportion of oxalate in these diets; rhubarb, spinach and beet are other common high oxalate-content foods. Vegetarians who consume greater amounts of vegetables will have a higher intake of oxalates, which may reduce calcium availability. This may be an increased risk factor for women, who require greater amounts of calcium in the diet. In humans, diets low in calcium and high in oxalates are not recommended but the occasional consumption of high oxalate foods as part of a nuritious diet does not pose any particular problem. ---------------------------------- http://tinyurl.com/63ken The hole truth: intracrystalline proteins and calcium oxalate kidney stones. Ryall RL, Fleming DE, Grover PK, Chauvet M, Dean CJ, Marshall VR. Department of Surgery, Flinders University School of Medicine, Flinders Medical Centre, Bedford Park, South Australia, Australia. rose.ryall@... The ultimate aim of our research is to understand the role of macromolecules in the formation of human kidney stones, particularly their interactions with calcium oxalate (CaOx) crystals. The invariable association of stones with proteins raises the possibility that proteins play a role in their formation, similar to the role of proteins in healthy biomineralization. Do these proteins induce mineralization? Are they merely a response to the disease process? Or are they protective molecules that were overwhelmed by mineral supersaturation? A protein of particular interest is fragment 1 (F1) of prothrombin. We have shown that mRNA for prothrombin is present in the kidney. Because the F1 fragment of prothrombin present in urine is slightly different from that found in the blood, we refer to this protein as " urinary prothrombin fragment 1 " (UPTF1). Available evidence suggests that the kidney manufactures the protein for protection against stone disease and that the protein has a directive role in stone formation. We now have evidence that proteins are interred within CaOx crystals precipitated from human urine, where it is distributed in continuous channels. These proteins could facilitate crystal deconstruction and removal after attachment to the renal epithelium and endocytosis. We suspect that the formation of CaOx crystals in the urine is a normal process designed to permit harmless disposal of an excess of calcium, oxalate, or both. The incorporation of proteins provides a second line of defense against stone formation by enabling the destruction and removal of retained crystals. Understanding the basic molecular strategies by which plants produce protein-containing CaOx crystals may provide insight into human CaOx stone formation. 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 In a message dated 10/12/04 9:26:53 AM Eastern Daylight Time, s.fisher22@... writes: I thought the steam *evaporates*? ______ ~~~~> Steam can't evaporate, because it already *is* vapor. Liquids evaporate, vapors don't. Did you mean you thought it disappears? ______ 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? _____ ~~~~~>That's doubtful for two reasons. First, anti-trypsins are glycoproteins, and proteins are easily denatured by heat. I don't know about the others, but that's probably the case or something similar to them. Oxalic acid does not have a shape and function dependent on weak bonds. The second reason is that the study I posted last year found that essentially all of the oxalate that was missing from the vegetables was found in the cooking water. There was a very, very, very tiny gap, but it wasn't significant, and it isn't clear that it would be attributable to the heat anyway. So, it can be safely said that heat has no significant effect on oxalates at all, IMO. ______ I just googled " heat labile oxalic acid " and couldn't find anything though. I know other acids are indeed heat-labile like ascorbic acid. ______ ~~~~~> I haven't looked into the heat-lability of ascorbic acid, but one thing I know is that the USDA shows a much higher vitamin C content for a baked potato than for a boiled/mashed potato, even though baked potatoes are cooked at twice the heat for four times as long. So I doubt that vitamin C is extremely heat-labile and probably not very heat-labile in dry foods. It may be somewhat heat-labile in milk and other wet foods (everything is destroyed more easily in water when heated, to my understanding), but I'd guess that most vitamin C loss that occurrs in cooking is also attributable to leaching into cooking water. _______ 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? ______ ~~~~> I'm sorry, I think I missed this. Was there a reference to drying reducing oxalates in your initial post? ______ 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. _____ ~~~~~> I think that would be best, but it would be sufficient in the case of boiling where all the heating water, or most of it, is recovered, to measure the oxalate content of the water, to give a rough idea. _____ 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. ______ ~~~~~> Why? That doesn't make sense to me. The oxalate, not water, is leaching from the foods. ______ 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? ______ ~~~~~> Considering that Sally recommends cooking, not soaking, egg whites, I'd guess that cooking should generally do the trick. But anti-trypsin is a protein, so I would guess it would be pretty heat-labile (though I generally object to using that term with reference to the study you posted, since the study doesn't study heat-lability per se). ____ >>I don't remember it. Do you still have it? I'd like to see it, if so. ____ ~~~~~> It's in the archives <weg> I don't have it saved on my comp. _____ >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. ____ ~~~~> Unless they are more incompetent in writing abstracts, I don't think we do. If they had a dry-heat control or measured the oxalate content of the water, it would be unambiguously abstract-worthy, and obviously much more important than the quantitative data present in the abstract. _____ >>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. _____ ~~~~~> I've never thrown out oatmeal water. I thought that was only for certain foods like beans and nuts. Chris 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 > Re: OXALATES > > > >In a message dated 10/12/04 9:26:53 AM Eastern Daylight Time, >s.fisher22@... writes: >I thought the steam *evaporates*? >______ > >~~~~> Steam can't evaporate, because it already *is* vapor. Liquids >evaporate, vapors don't. Did you mean you thought it disappears? 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. >______ >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? >_____ > >~~~~~>That's doubtful for two reasons. First, anti-trypsins are >glycoproteins, and proteins are easily denatured by heat. I don't >know about the others, >but that's probably the case or something similar to them. Oxalic >acid does >not have a shape and function dependent on weak bonds. The second >reason is >that the study I posted last year found that essentially all of >the oxalate that >was missing from the vegetables was found in the cooking water. What vegetables did they cook? >There was a >very, very, very tiny gap, but it wasn't significant, and it isn't >clear that >it would be attributable to the heat anyway. So, it can be safely >said that >heat has no significant effect on oxalates at all, IMO. 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 just googled " heat labile oxalic acid " >and couldn't find anything though. I know other acids are indeed >heat-labile >like ascorbic acid. >______ > >~~~~~> I haven't looked into the heat-lability of ascorbic acid, but one >thing I know is that the USDA shows a much higher vitamin C >content for a baked >potato than for a boiled/mashed potato, even though baked potatoes >are cooked at >twice the heat for four times as long. So I doubt that vitamin C is >extremely heat-labile and probably not very heat-labile in dry >foods. It may be >somewhat heat-labile in milk and other wet foods (everything is >destroyed more >easily in water when heated, to my understanding), but I'd guess >that most vitamin >C loss that occurrs in cooking is also attributable to leaching >into cooking >water. > 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. 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?? 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). 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. 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. >_______ >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? >______ > >~~~~> I'm sorry, I think I missed this. Was there a reference to drying >reducing oxalates in your initial post? 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... >>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. >____ > >~~~~> Unless they are more incompetent in writing abstracts, I >don't think we >do. If they had a dry-heat control or measured the oxalate content of the >water, it would be unambiguously abstract-worthy, and obviously much more >important than the quantitative data present in the abstract. Yes, you are right. Although I sometimes wonder if significant points of studies are *indeed* left out of abstracts. Although in this case, it would seem pretty absurd. >_____ > >>>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. >_____ > >~~~~~> I've never thrown out oatmeal water. I thought that was only for >certain foods like beans and nuts. I haven't had oatmeal in a while, but I generally throw out the water of everything I soak. I'd read before that there are several things, like saponins or tannins on the *surface* of some (or maybe all?) grains and that it's traditional practice to toss out the soaking water. So I do. Also, in your response you didn't address my comments below. Do you have any comment? >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 > > 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. Oxalobacter formigenes. That's the critter I was reading about that was associated with low incidence of kidney stones. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 13, 2004 Report Share Posted October 13, 2004 At 08:04 PM 10/13/04 -0000, you wrote: >Oxalobacter formigenes. That's the critter I was reading about that >was associated with low incidence of kidney stones. > > At the risk of having almost every single post of mine today be completely facetious ... Can anyone say " oxalobacter formigenes " six times really fast???? Try it. If you're not laughing at the end, I've not done my job. *See run. See run fast.* Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 20, 2004 Report Share Posted October 20, 2004 > Re: OXALATES > > > >In a message dated 10/18/04 9:45:20 AM Eastern Daylight Time, >s.fisher22@... writes: >Well, what's interesting is that the vitamin C content in regular potatoes >*decreases* with baking, which contradicts what happens with the *sweet* >potato. At first I hadn't seen regular raw potatoes listed, but just found >it now. It has 11.4 mgs/100 grams raw, and 13.5 mgs/100 grams >baked. You see >why I think the USDA database is fairly useless? >_____ > >~~~~> No, you've confused me. Did you type that sentence wrong? You're >showing the vitamin C increasing with baking as in the other example, not >decreasing, which fits the explanation offered by me and Mike. Oops! I don't know where I got that figure from. It's not correct. I think I scanned the entries too quickly and selected *just* skin, assuming it meant WITH skin. Here are the correct data for ascorbic acid content per 100 grams. raw: 19.7 mgs baked: 9.6 mgs (w/salt) boiled: 13 mgs (w/salt) boiled: 13 mgs (without/salt) So *baking* a potato (according to these data) decreases the ascorbic acid content approx. 20% more than boiling does in *potatoes*. Would salt interfere with ascorbic acid loss in baking? Apparently it doesn't in boiling. >(although if it >didn't, it wouldn't mean the data were useless, it would seem to >suggest that there >is a large heat-induced loss of vitamin C). That's what it looks like, n'est pas? Here's the sweet potato data: raw: 2.4 baked: 19.6 (without salt) boiled: 12.8 mgs (without SKIN). no data for boiled WITH skin.) So we're right back to what I was fussing about re the usefuleness of these data earlier - these data totally contradict each other. While the sweet potato data support your argument that the moisture lost during baking increases the percent of ascorbic acid, the potato data contradict it. What do you think the explanation is? > >________ >The regular potato data >contradicts your explanation, which I agree is the most obvious one. But >it's only based on 3(!) DATA POINTS. Any 3 potatoes in the United States >can't possibly represent the nutrient profile of the millions of potatoes >grown in this country. >_______ > >~~~~~> Why do they even bother using three? It's my understanding >that the >USDA's positions is that nutrient composition is dependent on species and >breed, and not affected by soil. So shouldn't *one* sample be >sufficient? If they >implicitly admit the need for a variety of samples, you'd think >they'd use a >lot more than three. It varies widely. I think the *raw* potato data that I just posted was based on 141 data points. The boiled sweet potato was based on 4 data points. You have an interesting point about them implicitly admitting the need for more data points. I'm pretty sure they KNOW that these data are largely based on soil health, they just don't want US to know that. That's probably why they went for decades without providing any NEW data, but just re-printed OLD data and put a new date on it. The declines in nutrient content is astounding when you look back about 60 years. Unless they change the way they measure nutrients, it's an indication that our soil sucks, which we already KNOW is the case, so the declining nutrient values of the USDA data just bolster a fact we already know. >_______ >This is why I think it may be even MORE confusing to >use USDA nutrient data to try to learn anything meaningful about nutrient >content of produce. A possible exception might be the drastic decline in >nutrients over several decades. >______ > >~~~~~> I think that would be useless as well, because there are unresolved >possible alternative explanations for the decline in nutrient >value that is >shown in successive USDA figures, mentioned in an article you >posted a couple >months ago, such as changes in the definition of " edible portion " >over time. While that may be so, I invoke your earlier argument about the reliability of the study you posted in which you argued that *logic* supported the conclusions of the study. In this case, I'd say logic AND *fact* support the declining nutrient values of produce as published by the USDA. It's absolutely no mystery that our soil health is rapidly declining. Therefore, it's fairly logical to deduce that the declining nutrient values of the USDA database reflect this, even though their data may also be influenced by things such as changes to the definition of " edible portion. " __ >The article she posted didn't say. I think it did say though that these >potatoes only contained *soluble* oxalates. Perhaps they are more prone to >destruction by heat or drying or fermentation, as someone else mentioned? >_____ > >~~~~~> If they are heat-labile, then being in wet heat would >probably have a >greater rate of destruction than dry heat. But since I still >haven't seen any >evidence that oxalates are destroyed by heat, and since I really >don't think >sun-drying would generate all that much heat anyway, Have you ever been to southern Florida??? LOL. I used to live there and I can assure you that even several *minutes* of sun exposure during certain times of the day and year can involve an *intense* amount of heat. Having said that, I think the temp. in the Andes may vary widely, so I don't know if it ever got " southern Florida " hot where these tribes sun-dried their potatoes or not. 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 23, 2004 Report Share Posted October 23, 2004 In a message dated 10/20/04 9:19:09 AM Eastern Daylight Time, s.fisher22@... writes: > Oops! I don't know where I got that figure from. It's not correct. I think I > scanned the entries too quickly and selected *just* skin, assuming it meant > WITH skin. Here are the correct data for ascorbic acid content per 100 > grams. > > raw: 19.7 mgs > baked: 9.6 mgs (w/salt) > boiled: 13 mgs (w/salt) > boiled: 13 mgs (without/salt) > > So *baking* a potato (according to these data) decreases the ascorbic acid > content approx. 20% more than boiling does in *potatoes*. Would salt > interfere with ascorbic acid loss in baking? Apparently it doesn't in > boiling. ______ ~~~~> Probably not, but moreover, I'd think that the salt would be added after boiling rather than before. ______ > >(although if it > >didn't, it wouldn't mean the data were useless, it would seem to > >suggest that there > >is a large heat-induced loss of vitamin C). > > That's what it looks like, n'est pas? ______ ~~~~~>It does, assuming that the skin is present in all samples. If the raw potato includes the skin, and the other two have the skin discarded, that would be a problem. Unfortunately, it doesn't appear to indicate one or the other. ______ > Here's the sweet potato data: > raw: 2.4 > baked: 19.6 (without salt) > boiled: 12.8 mgs (without SKIN). no data for boiled WITH skin.) > > So we're right back to what I was fussing about re the usefuleness of these > data earlier - these data totally contradict each other. While the sweet > potato data support your argument that the moisture lost during baking > increases the percent of ascorbic acid, the potato data contradict it. What > do you think the explanation is? _______ ~~~~~> I don't have one except to conclude, as you'd suggested, that the USDA are useless for this kind of analysis. _______ > It varies widely. I think the *raw* potato data that I just posted was based > on 141 data points. The boiled sweet potato was based on 4 data points. You > have an interesting point about them implicitly admitting the need for more > data points. I'm pretty sure they KNOW that these data are largely based on > soil health, they just don't want US to know that. That's probably why they > went for decades without providing any NEW data, but just re-printed OLD > data and put a new date on it. ________ ~~~~~> I think that that would be pretty consistent with their claim that the nutrition of a plant is dependent entirely on its genes. If the nutritive value wouldn't change, why bother taking new data? ________ > While that may be so, I invoke your earlier argument about the reliability > of the study you posted in which you argued that *logic* supported the > conclusions of the study. In this case, I'd say logic AND *fact* support the > declining nutrient values of produce as published by the USDA. It's > absolutely no mystery that our soil health is rapidly declining. Therefore, > it's fairly logical to deduce that the declining nutrient values of the USDA > database reflect this, even though their data may also be influenced by > things such as changes to the definition of " edible portion. " _____ ~~~~> Good point. Chris ____ " What can one say of a soul, of a heart, filled with compassion? It is a heart which burns with love for every creature: for human beings, birds, and animals, for serpents and for demons. The thought of them and the sight of them make the tears of the saint flow. And this immense and intense compassion, which flows from the heart of the saints, makes them unable to bear the sight of the smallest, most insignificant wound in any creature. Thus they pray ceaselessly, with tears, even for animals, for enemies of the truth, and for those who do them wrong. " --Saint Isaac the Syrian Quote Link to comment Share on other sites More sharing options...
Guest guest Posted October 24, 2004 Report Share Posted October 24, 2004 > Re: OXALATES > > > >> >(although if it >> >didn't, it wouldn't mean the data were useless, it would seem to >> >suggest that there >> >is a large heat-induced loss of vitamin C). >> >> That's what it looks like, n'est pas? >______ > >~~~~~>It does, assuming that the skin is present in all samples. >If the raw >potato includes the skin, and the other two have the skin discarded, that >would be a problem. Unfortunately, it doesn't appear to indicate >one or the other. >______ > They all included the skin. I just didn't write it down. They had separate data for skinless pototoes. 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 April 24, 2006 Report Share Posted April 24, 2006 I just read in Dr. Kaayla s' outstanding book, The Whole Soy Story, that cooking does not neutralise oxalates nearly to the extent that was previously believed. ~*~*~*~*~*~*~*~*~*~ Canfield ~We always grow in the direction in which we express ourselves.~ " The law of the Lord is perfect, converting the soul: the testimony of the Lord is sure, making wise the simple. " Psalm 19:7 Quote Link to comment Share on other sites More sharing options...
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