# Why exactly can't I cook with flaxseed oil
**URL:** https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634
**Category:** Factual Questions
**Created:** [October 10, 2005, 9:29pm UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634 "2005-10-10T21:29:23Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [October 10, 2005, 9:29pm UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634/1 "2005-10-10T21:29:23Z")
I have heard from several sources that you cannot cook with flaxseed oil (but that you can cook with milled flaxseeds) because it will denature the omega-3 fatty acids. However I keep reading stories that eating cooked fish is healthy because of the omega 3 content.
So why is it that eating cooked fish provides the benefits of omega-3s but supposedly if you cook something and use flaxseed oil (instead of vegetable oil) it will ruin the omega-3s of the flaxseed? Is there something to fish that keeps the omega-3 fatty acids stable or is it that only a small amount of omega-3s are destroyed in cooking?
Basically, why does adding flaxseed oil to a food when you cook it cause the omega-3 fatty acid to denature while the omega-3 fatty acids in fish still remain effective and active in the body even when you cook them?
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### Author:  [@Harmonix](https://boards.straightdope.com/u/Harmonix)
#### Post date: [October 10, 2005, 10:15pm UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634/2 "2005-10-10T22:15:36Z")
WAG.
I bet the oil is going to get alot hotter alot faster then any properly cooked fish.
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### Author:  [@Squink](https://boards.straightdope.com/u/Squink)
#### Post date: [October 10, 2005, 10:29pm UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634/3 "2005-10-10T22:29:57Z")
[Can Flax Seed Oil be Used for Cooking?](http://boards.straightdope.com/sdmb/showthread.php?t=332431&highlight=linseed)
Flax oil doesn’t denature, it oxidizes.
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### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [October 10, 2005, 10:54pm UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634/4 "2005-10-10T22:54:25Z")
> [@Squink](#):
>
> [Can Flax Seed Oil be Used for Cooking?](http://boards.straightdope.com/sdmb/showthread.php?t=332431&highlight=linseed)
>
> Flax oil doesn’t denature, it oxidizes.
I don’t get why eating cooked fish provides omega-3 benefits though. Fish is cooked at 400 F, and the omega-3s are still active enough to have an effect on things like demetia, depression and cardiovascular disease.
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### Author:  [@Squink](https://boards.straightdope.com/u/Squink)
#### Post date: [October 10, 2005, 11:15pm UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634/5 "2005-10-10T23:15:14Z")
> [@Wesley Clark](#):
>
> Fish is cooked at 400 F
The oil in which fish is cooked may reach 400°F, but the fish itself is held below ~212°F by its water content. If you cook it long enough to drive off the water and reach higher temperatures, you end up with tough, burnt fish.
The tissue structure of the fish impedes oxygen diffusion, so unsaturated oils in the cell membranes are protected from oxidation.
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### Author:  [@Mangetout](https://boards.straightdope.com/u/Mangetout)
#### Post date: [October 10, 2005, 11:23pm UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634/6 "2005-10-10T23:23:22Z")
[ul][li]The recipes I’ve seen to include flax seeds are things like multigrain bread; this does not reach the same temperatures during cooking as does frying oil.[/li][li]Flax seed oil oxidisies quite readily in contact with air, or at least some of its components do - notably the ones you’re interested in.[/li][li]fFax seed oil is also known as linseed oil - it has quite a strong waxy/oily taste of its own - there may be a tendency for anything you cook in/with large amounts of it, to taste like cricket bats.[/li][/ul]
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### Author:  [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)
#### Post date: [October 11, 2005, 1:12am UTC](https://boards.straightdope.com/t/why-exactly-cant-i-cook-with-flaxseed-oil/325634/7 "2005-10-11T01:12:31Z")
Also, I think the “delivery” of the omega-3’s in flaxseed is different than fish.
> [@](#):
>
> What is the difference between fish oil and flaxseed oil?
>
> Both fish and flax are good sources of omega-3’s, and for people who will not consume fish for any reason, flax will do. Flaxseed oil is also less expensive, which can be an important consideration as well. The main difference is that flaxseed oil contains only alpha- linoleic acid (ALA), which is the parent compound from which other omega-3 fatty acids are derived. This leaves it to your body to do the conversion to the other forms it needs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The problem is that the conversion is not always that efficient, and the body often uses the ALA for extra energy, leaving less for conversion to the other types. Fish oil, on the other hand, contains the other forms and delivers them directly to your body with no conversion necessary. Whatever form you decide to take, nutritionists recommend to back it up with an extra 400 IU of vitamin E (as mixed tocopherols) to prevent the fatty acids from breaking down too rapidly in your body.
Found that on [this site](http://www.shirleys-wellness-cafe.com/flaxoil.htm) which is kind of a “snakeoil” kind of site but the passage above doesn’t seem to be biased.