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Medical Forum / General / Nutrition / March 2008Cod Liver Oil Poisonous?
I'm trying to determine the veracity of a claim made by Ray Peat on his site, raypeat.com. Here is the claim: "With just a normal amount of vitamin E in the diet, cod liver oil is certain to be highly oxidized in the tissues of a mammal that eats a lot of it, and an experiment with dogs showed that it could increase their cancer mortality from the normal 5% to 100%." I cannot find any online reference to the "experiment with dogs that showed that it (cod liver oil) could increase their cancer mortality from the normal 5% to 100%." I'm genuinely interested in Ray Peat's viewpoint, and find many of his insights valuable, so I would appreciate it if anyone can provide a link to any study that supports this statement regarding cod liver oil and canine cancer mortality. I'm literally trying to determine whether cod liver oil is something that should, or should not, be included in my diet. Thanks for your help. Wanderer It's a matter of degree, but I don't see good evidence for any real "benefit" from it, because there are much safer alternatives. Assuming you are in good health, if you stuck a pin in some cod liver oil, and just took that amount each day, your body could deal with it. If you took a few fish oil pills a day, I'd be very concerned. Somewhere in the middle is the danger threshold, but as I said, why bother? What do you think you need it for? You might want to take a look on my free site, because examine some of the old evidence (which was available over the internet: http://groups.msn.com/TheScientificDebateForum-/ There's little doubt that such an experiment would yield such results (it's biochemistry at the most basic level possible, and there is no good contradictory evidence). I've been challenging fish oil supplement advocates to repeat this kind of experiment, with the "loser" to pay all expenses, but nobody has shown the slightest interest in doing this. My guess is that at least some of these advocates have conflicts of interest in some way, whereas I'm an independent scholar who once took omega 3 supplements. After I decided to examine the evidence closely (instead of relying on "expert opinion"), I realized what a huge mistake I was making. Denham Harman was the first to talk about the dangers of free radicals, so you might want to look into his research as well. > It's a matter of degree, but I don't see good evidence for any real > "benefit" from it, because there are much safer alternatives. [quoted text clipped - 20 lines] > was the first to talk about the dangers of free radicals, so you might > want to look into his research as well. Thanks very much for your response and supporting research. I appreciate your help. >> I'm genuinely interested in Ray Peat's viewpoint, and find many of >> his insights valuable, so I would appreciate it if anyone can >> provide a link to any study that supports this statement regarding >> cod liver oil and canine cancer mortality. > > There's little doubt that such an experiment would yield such results ... > I'm an independent scholar It seems that you don't have the refercence. A scholar studying a problem would ask Ray Peat for the reference to the study. Why don't you? After all, you repeatedly refer to this study. On Mar 1, 2:05 am, DZ <3...@309863296.2413615863.26934.10335.7655> wrote: > monty1...@lycos.com wrote: > >> I'm genuinely interested in Ray Peat's viewpoint, and find many of [quoted text clipped - 9 lines] > problem would ask Ray Peat for the reference to the study. Why don't > you? After all, you repeatedly refer to this study. Once I tried to track down that study and ended up with some old reference without abstract or full text and it was some sort of a meeting/party speech record only. Same as with the 1940 EFAD refutation studies. I admit that but this doesn't automatically mean that the Ray Peat's ideas are wrong. The fish oil/EFA camp has no clear evidence either! I would be very happy if someone can prove me wrong with clear experimental evidence showing the long term benefits of EFA supplementation (not any review article/questionare statistics or guideline or government policy please). Taka P.S.: By EFA or EFAD I mean the Omega-3 and Omega-6 fatty acids, not the Omega-9 Mead acid in this case >> monty1...@lycos.com wrote: >> >> I'm genuinely interested in Ray Peat's viewpoint, and find many of [quoted text clipped - 13 lines] > reference without abstract or full text and it was some sort of a > meeting/party speech record only. Actually, I have a full text, scanned copy of this speech (by Sinclair). There is no mentioning of dogs in it. On Mar 1, 12:21 pm, DZ <13...@47921337.2019420451.13776.30507.18345> wrote: > >> monty1...@lycos.com wrote: > >> >> I'm genuinely interested in Ray Peat's viewpoint, and find many of [quoted text clipped - 16 lines] > Actually, I have a full text, scanned copy of this speech > (by Sinclair). There is no mentioning of dogs in it. Could you possibly OCR and post it? There are many Sinclair's papers from the seventies dealing with EFAs and EFAD (e.g. PMID: 1186900) without abstracts. I think it was among them but I don't have the time to do an extensive search right now. I think Ray Peat is answering questions by e-mail so we may ask him directly? Also here is a more extensive reference list from his site (he should be really putting the reference numbers next to his claims in the text ...): http://raypeat.com/articles/articles/fats-degeneration.shtml Taka > Could you possibly OCR and post it? > [quoted text clipped - 9 lines] > > Taka This is essentially the same claim I originally questioned, with the added information that the study was performed in the late 1940s, and an additional suggestion that the study led to the "decreased use of cod liver oil": "Between the first and second world wars, cod liver oil was recommended as a vitamin supplement, at first as a source of vitamin A, and later as a source of vitamins A and D. But in the late 1940s, experimenters used it as the main fat in dogs¹ diet, and found that they all died from cancer, while the dogs on a standard diet had only a 5% cancer mortality. That sort of information, and the availability of synthetic vitamins, led to the decreased use of cod liver oil." I actually did request a source for this information through Ray Peat's Web site and received a reply that Mr. Peat was out of the country and did not have access to his archives. The reply suggested that I search online and that I would find many studies supporting this conclusion of cod liver oil causing 100% cancer mortality in dogs. I have searched using every combination of words I can think of, and have found reference to no such studies. In fact, most of the studies that do come up seem to involve the beneficial effects of cod liver oil for dogs. Nevertheless, I remain open-minded about this. If anyone can produce the study that Mr. Peat refers to, I would be most appreciative. Thanks to all who have contributed their insights on this topic. Wanderer > This is essentially the same claim I originally questioned, with the added > information that the study was performed in the late 1940s, and an additional [quoted text clipped - 6 lines] > they all died from cancer, while the dogs on a standard diet had > only a 5% cancer mortality. Even producers of fish oild supplements write on the bottle something like a 1 g as a recommended dose. How do we go from 10 cal to the main source of fat? Perhaps majority of "supplements" would be harmful if they constituted a major part of the diet. The leap of faith is this: if EFA increase free radical formation, then they must be non-essential and should be avoided altogether. > On Sat, 1 Mar 2008 01:19:20 -0500, Taka wrote > (in article [quoted text clipped - 33 lines] > combination of words I can think of, and have found reference to no such > studies. Same here ... One problem is that the articles as old as 1940 are not listed in PubMed. There are newer papers with indirect evidence but that is not enough especially when the review articles about the benefits of Omega-3 overcrowd them. The people who have access to the old publications and books like Monty or Ray Peat should at least show clear citations on their sites ... One thing I have learned the hard way though is to keep the PUFAs as low as possible (the "adverse" effects of EFAD are hard to see in adult people anyway). I have not seen any benefits from small doses of fish or borage oil so supplementing is just wasting money. I remember a study in Medline demonstrating that to see some therapeutic antiinflammatory effects you need to take Omega-3's in quite large doses which are definitely dangerous. Remember that any chemotherapy is not affecting only the bad cells but also the good stem cells which you need for long term body maintenance. Taka > In fact, most of the studies that do come up seem to involve the > beneficial effects of cod liver oil for dogs. [quoted text clipped - 4 lines] > > Wanderer Something similar on the topic from Wikipedia which has better references than the Ray Peat's site: QUOTE: The role of dietary oxidized fats / lipid peroxidation (rancid fats) in humans is not clear. Laboratory animals fed rancid fats develop atherosclerosis. Rats fed DHA-containing oils experienced marked disruptions to their antioxidant systems, as well as accumulated significant amounts of peroxide in their blood, livers and kidneys.[10] In another study, rabbits fed atherogenic diets containing various oils were found to undergo the greatest amount of oxidative susceptibility of LDL via polyunsaturated oils.[11] In a study involving rabbits fed heated soybean oil, "grossly induced atherosclerosis and marked liver damage were histologically and clinically demonstrated". UNQUOTE. SOURCE: http://en.wikipedia.org/wiki/Atherosclerosis > Something similar on the topic from Wikipedia which has better > references than the Ray Peat's site: [quoted text clipped - 12 lines] > > SOURCE: http://en.wikipedia.org/wiki/Atherosclerosis Sounds entirely plausible. I'm still looking for the supporting research for the claim that dogs fed a diet high in COD LIVER OIL experienced 100% cancer mortality. It's this specific claim that interests me, because cod liver oil is so often touted as a healthful oil (by researchers like Mary Enig for instance). It was that particular finding from that particular study that I found so alarming. I realize there are studies supporting the idea that eating rancid fats is not a great idea. I don't find that surprising. On Feb 28, 3:40 pm, Wanderer <jake_fan...@yahoo.com> wrote: "With just a normal amount of vitamin E in the diet, cod liver oil is certain to be highly oxidized in the tissues of a mammal that eats a lot of it, and an experiment with dogs showed that it could increase their cancer mortality from the normal 5% to 100%." << Theoretically it is possible .. due to the increased oxidative stress. "Susceptibility of LDL to oxidation was higher after EPA+DHA intervention than after the ALA interventions" American Journal of Clinical Nutrition, Vol. 77, No. 4, 783-795, April 2003 (c) 2003 American Society for Clinical Nutrition -------------------------------------------------------------------------------- Original Research Communication Plant- and marine-derived n-3 polyunsaturated fatty acids have differential effects on fasting and postprandial blood lipid concentrations and on the susceptibility of LDL to oxidative modification in moderately hyperlipidemic subjects1,2,3 Yvonne E Finnegan, Anne M Minihane, Elizabeth C Leigh-Firbank, Samantha Kew, Gert W Meijer, Reto Muggli, Philip C Calder and Christine M Williams 1 From the Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, University of Reading, Reading, United Kingdom (YEF, AMM, ECL-F, and CMW); the Institute of Human Nutrition, School of Medicine, University of Southampton, Southampton, United Kingdom (SK and PCC); the Unilever Health Institute, Unilever R&D Vlaardingen, Vlaardingen, Netherlands (GWM); and Roche Vitamins Ltd, Basel, Switzerland (RM). Background: Dietary -linolenic acid (ALA) can be converted to long- chain n-3 polyunsaturated fatty acids (PUFAs) in humans and may reproduce some of the beneficial effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cardiovascular disease risk factors. Objective: This study aimed to compare the effects of increased dietary intakes of ALA and EPA+DHA on a range of atherogenic risk factors. Design: This was a placebo-controlled, parallel study involving 150 moderately hyperlipidemic subjects randomly assigned to 1 of 5 interventions: 0.8 or 1.7 g EPA+DHA/d, 4.5 or 9.5 g ALA/d, or an n-6 PUFA control for 6 mo. Fatty acids were incorporated into 25 g of fat spread and 3 capsules to be consumed daily. Results: The change in fasting or postprandial lipid, glucose, or insulin concentrations or in blood pressure was not significantly different after any of the n-3 PUFA interventions compared with the n-6 PUFA control. The mean (± SEM) change in fasting triacylglycerols after the 1.7-g/d EPA+DHA intervention (-7.7 ± 4.99%) was significantly (P < 0.05) different from the change after the 9.5-g/d ALA intervention (10.9 ± 4.5%). The ex vivo susceptibility of LDL to oxidation was higher after the 1.7-g/d EPA+DHA intervention than after the control and ALA interventions (P < 0.05). There was no significant change in plasma -tocopherol concentrations or in whole plasma antioxidant status in any of the groups. Conclusion: At estimated biologically equivalent intakes, dietary ALA and EPA+DHA have different physiologic effects. Key Words: -Linolenic acid * eicosapentaenoic acid * docosahexaenoic acid * polyunsaturated fatty acids * n-3 fatty acids * lipids * plasma fatty acid * LDL oxidation * moderately hyperlipidemic subjects * triacylglycerol Who loves ya. Tom Jesus Was A Vegetarian! http://jesuswasavegetarian.7h.com Man Is A Herbivore! http://tinyurl.com/a3cc3 DEAD PEOPLE WALKING http://tinyurl.com/zk9fk > I'm trying to determine the veracity of a claim made by Ray Peat on his site, > raypeat.com. Here is the claim: [quoted text clipped - 19 lines] > > Wanderer > On Feb 28, 3:40 pm, Wanderer <jake_fan...@yahoo.com> wrote: "With just > a normal amount of vitamin E in the diet, cod liver oil is certain to [quoted text clipped - 12 lines] > 2003 > (c) 2003 American Society for Clinical Nutrition Many thanks for providing the results of this study. I really appreciate your taking the time to enlighten me. > I'm literally trying to determine whether cod liver oil is something that > should, or should not, be included in my diet. There are better alternatives. Cod liver oil is high in vitamin A to the point of being toxic. Get your vitamin D from other sources. -- Ron >> I'm literally trying to determine whether cod liver oil is something that >> should, or should not, be included in my diet. [quoted text clipped - 4 lines] > -- > Ron Thanks for your suggestion, Ron. What supplements do you recommend for vitamin A and/or vitamin D? (That is, if you recommend any supplements.) I've noticed that many of the available supplements contain stearic acid, which according to what I have been reading lately, has an immune suppressive effect. And the best food source of vitamin D seems to be oily fish, which brings us back to square one.I would be very grateful for your comments. > Thanks for your suggestion, Ron. What supplements do you recommend for > vitamin A and/or vitamin D? (That is, if you recommend any supplements.) I've > noticed that many of the available supplements contain stearic acid, which > according to what I have been reading lately, has an immune suppressive > effect. And the best food source of vitamin D seems to be oily fish, which > brings us back to square one.I would be very grateful for your comments. I am currently taking a 2400 IU vitamin D gelatin capsule. I don't take vitamin A, but do eat carrots which contain carotene which is a safe way to get vitamin A. A teaspoon of cod liver oil has about 100% of the vitamin A RDA, so it is safe in that amount. Fish isn't the source of vitamin D3 supplements, since it can be produced more economically artificially. Stearic acid is a saturated fatty acid and is a sizeable portion of many diets and so the small amounts in supplements is not likely to be significant problem. -- Ron > I'm trying to determine the veracity of a claim made by Ray Peat on his site, > raypeat.com. Here is the claim: [quoted text clipped - 15 lines] > I'm literally trying to determine whether cod liver oil is something that > should, or should not, be included in my diet. For what it's worth, I found the following through http://www.orthomolecular.org/nutrients/fats.shtml "The main difference between cod liver oil and fish oil is that cod liver oil is high in vitamin D. In warm weather, the sunshine produces high and usually sufficient levels of vitamin D without any supplementation necessary. It is not recommended consuming cod liver oil in the warm weather months or climates, as this can result in an excess of vitamin D in your system and consequential complications. Conversely, in cool weather, your body needs more vitamin D, and so cod liver oil versus fish oil is recommended in the cool weather months or climates. A general rule is, take cod liver oil from autumn to early spring, and fish oil from late spring through the end of summer. Adjust accordingly the closer or farther from the equator you live." Needless to say, I have no use for it here in Miami; but I do take a gram of salmon oil a day. :-)  SignatureMarshall Price of Miami Known to Yahoo as d021317c >> I'm trying to determine the veracity of a claim made by Ray Peat on >> his site, raypeat.com. Here is the claim: [quoted text clipped - 33 lines] > Needless to say, I have no use for it here in Miami; but I do take a > gram of salmon oil a day. :-) I need 4000 IU per day IN THE SUMMER here in Utah to get my vitamin D blood levels just barely into the low end of normal. It takes 7000 IU to get my vitamin D levels in the middle of the lab reference range in the winter. My latitude is about 40.5 degrees North with an elevation of about 1500 meters. Considering the recent study on 1000 IU/day reducing cancer rates by 77% (years 2-4), I'd say supplementation is recommend for almost everyone in the USA. SignaturePramesh Rutaji p297tongue6221@newsguy.com - remove tongue to reply >>> I'm trying to determine the veracity of a claim made by Ray Peat on >>> his site, raypeat.com. Here is the claim: [quoted text clipped - 42 lines] > (years 2-4), I'd say supplementation is recommend for almost everyone in > the USA. (That's very interesting. I don't know the vitamin D status of my blood, but take 1000 IU/day anyway.) I certainly hope somebody else steps in with useful information about cod liver oil. SignatureMarshall Price of Miami Known to Yahoo as d021317c |
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