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Altered EFA due COOKING good - altered EFA due to RANCIDITY bad - why ?

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  • Altered EFA due COOKING good - altered EFA due to RANCIDITY bad - why ?

    Hi Everyone,
    A simple sounding question that has been giving me trouble for a while. Hopefully someone on here can explain it to me.

    I understand that Polyunsaturated Essential Fatty Acids are less stable than Monounsaturates, which are less stable than Saturated fat - which in turn increases the risk of the oils going rancid as oxygen infiltrates the carbon bonds that are not saturated with hydrogen atoms. We all know rancidity is bad.

    I dont understand the process that occurs due to cooking regarding polyunsaturated oils. I would assume the heat alters the oil in some way ? -if so, is this alteration beneficial or harmful to human health ? I would assume the very fragile nature of polyunsaturates would mean that they have a very low 'smoke point' - after all, there has been much discussion on cooking with olive oil (much more stable than fish oil) on this site.

    Basically, how can cooking fish not alter the fish oils inside, the same way oxygen does when it makes the oils go rancid ?

    Many thanks in advance for anyone that can solve this one for me - i hope there's a post somewhere i can be linked to .

  • #2
    Sorry, can't help you on cooking, but when oxygen binds with PUFA's, the result is rancidity. Bet you knew that! But rancid fats destroy other vital nutrients in the body, like Vit E. The only reason I became aware of this was when a frugal goatkeeping friend used up the last of her Vit A-D-E food supplement for her pregnant goats. She figured she was saving money by not throwing away rancid oil. But at 3 weeks of age, her little goat kids bouncing around their pen would suddenly drop dead. Autopsies revealed heart attacks, and the prime culprit was the rancid oil.

    Unless the putative fish that you are cooking is totally exposed to air while being cooked, I sincerely doubt if the fish oils can go rancid, surrounded as they are by tissue. I've heard that's why you shouldn't scramble eggs, (Mercola) but, who knows?

    Comment


    • #3
      Thanks for the reply.

      I guess there would be some 'denaturing' going on then? in the tissues exposed to the most air ?

      Its a strange one - i hope someone has some definitive info.

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      • #4
        Originally posted by danandvicky View Post
        Thanks for the reply.

        I guess there would be some 'denaturing' going on then? in the tissues exposed to the most air ?

        Its a strange one - i hope someone has some definitive info.
        Well, in my internet forays, I came across some more info on rancid fats by Bruce Fife:

        Rancid Oils

        Still looking for actions of cooking. HTH

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        • #5
          And this is what I came up with, from the Blog of Dr Eades:

          I got an article in my inbox today about the risk of oxidized fats in fish oil capsules, even those that are well within the expiration date on the bottle.

          "We wrote about this very thing in the Protein Power LifePlan back in 2000.

          Fish oil is primarily EPA and DHA, both of which are extremely unsaturated. And, as we all know, the greater the degree of unsaturation, the greater the propensity to go rancid. When these oils go rancid (or “go off” as the Brits put it) they don’t go from being healthful to simply becoming neutral, they actually convert to harmful oxidized fats called lipid peroxides."Endquote

          From what I can determine, eat your fish fresh, cook it gently and consume at once. Fish oils are not as stable as saturated fats, and fish rot easily, which means they're rancid. Cooking and eating correctly means you are consuming the fish before it gets a chance to harm you. Many fish oil supplements on market are rancid, despite the expiration date.

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          • #6
            Hi Paysan,
            many thanks for the replies and for the extra research.

            The stuff from Dr Eades appears to be a restatement of part of my question and your musings dont really answer it either. Im trying to find out how to, or if it is even possible to, cook and eat fish 'correctly' due to the inherent nature of polyunsaturated fats. I wonder how long is it before oily fish become harmful ? 2-3 days perhaps for the oils to start to oxidise ? and when cooked, at what temperature does the heat start to have a harmful effect on the oils ?

            I havent seen anything on these forums or anywhere else for that matter that can explain my original question.

            If polyunsaturates are so delicate and go rancid at the drop of a hat, surely cooking must be harmful when it comes to oily fish ?

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            • #7
              Saturated fat is more stable than monounsaturated fat, which is more stable than polyunsaturated fats. It all has to do with the number of double bonds they contain. The double bonds have missing hydrogen atoms and hence are chemically unstable and hence easily broken by heat. Saturated fat has no double-bond. Monunsaturated has one. Polyunsaturated has multiple double bonds.

              Processed polyunsaturated oils in bottles are not healthy and should not be used for cooking as they are so easily damaged (oxidized) by heat. The polyunsaturated oils in the store shelf are probably already damaged due to the heat in processing the oil. I use saturated oil (such as coconut) oil for cooking.

              The polyunsaturated oil (DHA and EPA) from fish is fine and I try to eat lots of fish. Sure, the cooking of the fish may damage a little bit of it. But the benefits outweighs. If you lightly steam the fish, it is best. Deep fried is a big no-no.

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              • #8
                Sashimi
                Four years Primal with influences from Jaminet & Shanahan and a focus on being anti-inflammatory. Using Primal to treat CVD and prevent stents from blocking free of drugs.

                Eat creatures nose-to-tail (animal, fowl, fish, crustacea, molluscs), a large variety of vegetables (raw, cooked and fermented, including safe starches), dairy (cheese & yoghurt), occasional fruit, cocoa, turmeric & red wine

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                • #9
                  "Saturated fat is more stable than monounsaturated fat, which is more stable than polyunsaturated fats. It all has to do with the number of double bonds they contain. The double bonds have missing hydrogen atoms and hence are chemically unstable and hence easily broken by heat. Saturated fat has no double-bond. Monunsaturated has one. Polyunsaturated has multiple double bonds."

                  My initial post includes the chemistry - im aware of these facts. Also, i am not suggesting we should use fish oil to cook with - im asking if there is damage to the PUFA's in oily fish if it is cooked. I love some grilled(broiled) mackerel, herring or sardines but if its as harmful as guzzling a glass of rancid cod liver oil, then i would like to know about it.

                  Im assuming that it isnt harmful to cook oily fish otherwise there should be some science somewhere but i havent heard any argument or even questions either way. This is the thing that baffles me.

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                  • #10
                    Originally posted by danandvicky View Post
                    "Saturated fat is more stable than monounsaturated fat, which is more stable than polyunsaturated fats. It all has to do with the number of double bonds they contain. The double bonds have missing hydrogen atoms and hence are chemically unstable and hence easily broken by heat. Saturated fat has no double-bond. Monunsaturated has one. Polyunsaturated has multiple double bonds."

                    My initial post includes the chemistry - im aware of these facts. Also, i am not suggesting we should use fish oil to cook with - im asking if there is damage to the PUFA's in oily fish if it is cooked. I love some grilled(broiled) mackerel, herring or sardines but if its as harmful as guzzling a glass of rancid cod liver oil, then i would like to know about it.

                    Im assuming that it isnt harmful to cook oily fish otherwise there should be some science somewhere but i havent heard any argument or even questions either way. This is the thing that baffles me.
                    Would the fact that generations of seafaring folk and coast dwellers didn't drop dead en masse add anything to the safety of fish oils in your mind?

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                    • #11
                      I would not worry about cooking fish damaging the oils. Cooked fish is the best way to get DHA and EPA omega-3 fatty acids. It is a much better way than taking fish oil supplements. Although some people may need supplements in addition to eating lots of fish.

                      You are doing the right thing by consuming grilled (broiled) mackerel, herring or sardines. Eating cooked fished is safer than avoiding fish.

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                      • #12
                        Originally posted by BlissfulWriter View Post
                        I would not worry about cooking fish damaging the oils. Cooked fish is the best way to get DHA and EPA omega-3 fatty acids. It is a much better way than taking fish oil supplements.
                        WHY would you not worry about it ? What do you know about the cooking process that makes cooked oily fish safe?

                        Also, what do you mean by "best way" ?

                        safest ?
                        most efficate way?

                        This is the kind of thing I am trying to avoid - blanket statements with very vague wording such as 'best way' and 'i would not worry about it'. There needs to be reasoning or some kind of peer reviewed data behind such statements

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                        • #13
                          Originally posted by Paysan View Post
                          Would the fact that generations of seafaring folk and coast dwellers didn't drop dead en masse add anything to the safety of fish oils in your mind?
                          NO. Not at all - firstly, can you prove that seafarers live a comparatively long life?

                          Secondly, do you have any data to suggest all seafarers and coast dwellers consume lots of oily fish ?

                          Thirdly, can you be certain that they cooked the oily fish ?

                          I am just trying to investigate this stuff without any preconceptions. It seems followers of Marks Daily Apple are just as quick to accept or even just make up their own 'facts' or 'data' to support their own beliefs rather than actually wanting to find out real truths.

                          Im pretty sure that primal/paleo followers are heading towards avoiding ALL PUFA`s for the reasons associated with my initial post ( i.e. the inherent instability of PUFA`s).

                          Disclaimer : i know we need some PUFA`s which is why certain PUFA`s are dubbed 'essential oils'. Perhaps i should have stated 'heading toward avoiding ALL PUFA`s to a certain extent'.

                          The fact that nobody has come up with a decent explanation yet makes me question this issue even further - its a shame others dont appear to have a questioning nature - and very surprising as they probably arrived here due to questioning their conventional information sources.

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                          • #14
                            OK, I'm a bit of a history buff, and have read mega-tomes over the last few decades. Along the way, I read about coast dwellers and sea faring peoples. They were not immune to ills that plague the human race, but the evidence is strong that they didn't die of heart attacks. I recently bought "The Greenland Mummies" about some mummified burials of some women and children. The only thing certain is that they didn't die of violence, and that they lived on a mostly marine diet. It might interest you to learn that they likely did consume fermented fish oils, along with raw blubber and cooked oily fish. Unlike my friend's unfortunate kid goats, they did not die of heart attacks. Cancer in one case, yes. Exposure in the infant- very possibly. Starvation and inability to get around, probably. But of their oily fish diet, no question at all. And written records of the few Norsemen that lived in Greenland at the same time as these 500 yr old mummies, indicated that botulism, or food poisoning from rotten meat sometimes did the Inuit in. But I am pretty sure they did not consume any plant-sourced PUFA's. So there you have it - you can 1, eat fish raw, fresh or rotten and take your chances. 2. you can eat fish cooked, fresh or rotten, and take your chances. Frankly , other than olichan grease which was fermented fish oil, and very stable, most natives want their fish fresh and cooked.

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                            • #15
                              Originally posted by danandvicky View Post
                              ...

                              Also, what do you mean by "best way" ?

                              safest ?
                              most efficate way?

                              ...
                              I meant that eating cooked fish is the safer and the more efficacious way of getting omega-3 than from supplements. The problem with supplements is that there is a higher chance of the omega-3 being damaged due to the high-temperature processing and forming gel capsules. Plus the supplements are not transported and stored in a refrigerated fashion. Wherea, fish are transported in a refrigerated or frozen form. The quick light steaming to cook the fish does not cause the lost of efficacy because studies have shown that people who eat fish are getting benefits that those who do not. Here are some references.

                              Mercury from fish is not a problem either as long as the fish has more selenium than mercury, which most commercially sold fish has -- except sharks, pilot whale, whale meat, and possibly swordfish. . Reference in this podcast. Also watch this YouTube.

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