2

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Frying and oxidation (refined olive oil no more likely to oxidize than lard?)

Answered on August 19, 2014
Created January 12, 2013 at 7:09 PM

As an example, let me compare lard to refined olive oil. Both have sufficiently high smoke points to make them seemingly suitable for frying. It seems most here (especially if the source is a pastured pig) seem to agree that frying in lard is perfectly healthy. However, some seem concerned about frying with refined olive oil due to the oxidation of the oil.

From http://en.wikipedia.org/wiki/Lard, the fat composition of lard is:

  • Saturated fat: 38-43%
  • Monounsaturated fat: 47-50%
  • Polyunsaturated fat: 6-10%

And, from http://en.wikipedia.org/wiki/Olive_oil, for olive oil it is:

  • Saturated fat: 8-25%
  • Monounsaturated fat: 55-86%
  • Polyunsaturated fat: 3-21%

Given that they are both within somewhat similar ranges in terms of polyunsaturated fat and monounsaturated fat, is it really reasonable to be more worried about oxidation when frying with refined olive oil? Why?

Also, what specifically are the negative consequences of consuming oxidized fats? I understand that when fatty acids oxidize within our bloodstreams that is likely a bad thing, but is that really the same as consuming fats that are already oxidized? Or something other negative consequence? Would oxidation affect the flavor of the oil (i.e., is it something that we can detect after frying)?

Note: I do realize there may be other reasons to avoid refined olive oil as detailed in this thread. I'm just wondering if oxidation is a valid one.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on January 12, 2013
at 10:52 PM

@Matt - thanks for the article. Really interesting. I'm always amazed by how much thought/work/effort goes in behind the scenes at a farm.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on January 12, 2013
at 10:36 PM

Pig farmers, particularly ones that produce air-cured product, know that pigs on grass have too much PUFA to make quality product. Corn-feeding also produces pork with too much PUFA. Supposedly the best fat is produced by fallen fruit, acorns, etc... as well as grains like rye and wheat. See: http://woolypigs.com/_austrianmeattheory.html#cfc

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on January 12, 2013
at 10:33 PM

Great response. Thank you.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on January 12, 2013
at 10:27 PM

I didn't downvote either, but I do agree with Mscott. I do like the confidence in the response though. :)

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 09:19 PM

Well maybe I'll get two more downvotes so I can delete this answer and at least get a peer pressure badge, lol, I really thought this answered his question too. Thanks for clarifying,

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on January 12, 2013
at 09:15 PM

Oxidation in the study you posted is just referring the process of metabolizing fats into energy in the mitochondria, which is not a bad thing, unlike the oxidation of fatty acids by free radicals, which is accelerated by high heat and is definitely a bad thing.

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 09:05 PM

And it looks like once ingested olive oil actually does oxidize more. But I guess he's asking how fast does oil oxidize when cooking below the smoke point and does one oxidize faster than the other and what effects would that have? It still seems very relevant that after its fried and he consumes it any additional oxidation would be notable though.

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 09:02 PM

Okay, I'm thinking that he was asking about frying with olive oil vs saturated fat and how since they are kinda similar does one necessarily oxidize more than the other into the food and if so how would that effect his health.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on January 12, 2013
at 08:58 PM

I wasn't the one who downvoted this btw, but he's asking about oxidation of fats to dangerous compounds peroxides during frying, not oxidation in a metabolizing sense in the body, which is a separate thing. And yeah, passing smoke point *may* increase the rate of oxidation, but that doesn't mean they won't oxidize at a significant rate below the smoke point.

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 08:56 PM

Maybe I'm misunderstanding something?

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 08:54 PM

In here I show that olive oil oxidized in the participants to a greater extent than saturated fat. I assume he is going to eat whatever he fries are you saying an in Vitro study would be more relevant? If so why? And passing the smoke point of any oil Increases the rate of oxidation.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on January 12, 2013
at 08:45 PM

I don't think in vivo fatty acid oxidation or smoke point are very relevant to this particular question.

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 08:34 PM

They don't fry with the oils though, for that I would say as long as you aren't passing the smoke point for the given oil then you're good. http://en.wikipedia.org/wiki/Smoke_point

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2 Answers

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A2c38be4c54c91a15071f82f14cac0b3

(12682)

on January 12, 2013
at 10:32 PM

I don't think there's likely to be much difference in lipid oxidation when frying with either type of fat. This study, for example, found that frying pork chops in olive oil and lard produced similar amounts of the lipid oxidation product MDA. Frying with butter, for the record, produced less MDA than both.

This isn't to say pastured lard isn't healthier than refined olive oil, I think it is, but not because it's less prone to oxidation during frying.

Eating heavily heated fats (especially those with lots of PUFA's) may increase the risk of heart disease (among other maladies) by doing things like decreasing the oxidative stability of serum and lipoproteins (2,3), lowering paraoxonase, and increasing VCAM-1. I won't cite animal studies, but there are a lot of rat studies demonstrating possible risks of consuming oxidized oils.

This is primarily relevant to fats with high PUFA content. Pastured lard and refined olive oil don't have much in the way of antioxidants, but they're low in PUFA's so I think they both should be fine to cook with, though a fat with more antioxidants (like virgin olive oil), less PUFA's (like butter or tallow), or both (like virgin coconut oil) might be better though.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on January 12, 2013
at 10:52 PM

@Matt - thanks for the article. Really interesting. I'm always amazed by how much thought/work/effort goes in behind the scenes at a farm.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on January 12, 2013
at 10:36 PM

Pig farmers, particularly ones that produce air-cured product, know that pigs on grass have too much PUFA to make quality product. Corn-feeding also produces pork with too much PUFA. Supposedly the best fat is produced by fallen fruit, acorns, etc... as well as grains like rye and wheat. See: http://woolypigs.com/_austrianmeattheory.html#cfc

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on January 12, 2013
at 10:33 PM

Great response. Thank you.

-1
Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 08:33 PM

I think this unequivocally answers your question: http://www.ncbi.nlm.nih.gov/pubmed/12037652 . Let me know what you think.

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 09:05 PM

And it looks like once ingested olive oil actually does oxidize more. But I guess he's asking how fast does oil oxidize when cooking below the smoke point and does one oxidize faster than the other and what effects would that have? It still seems very relevant that after its fried and he consumes it any additional oxidation would be notable though.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on January 12, 2013
at 08:58 PM

I wasn't the one who downvoted this btw, but he's asking about oxidation of fats to dangerous compounds peroxides during frying, not oxidation in a metabolizing sense in the body, which is a separate thing. And yeah, passing smoke point *may* increase the rate of oxidation, but that doesn't mean they won't oxidize at a significant rate below the smoke point.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on January 12, 2013
at 08:45 PM

I don't think in vivo fatty acid oxidation or smoke point are very relevant to this particular question.

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 08:34 PM

They don't fry with the oils though, for that I would say as long as you aren't passing the smoke point for the given oil then you're good. http://en.wikipedia.org/wiki/Smoke_point

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 08:56 PM

Maybe I'm misunderstanding something?

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 08:54 PM

In here I show that olive oil oxidized in the participants to a greater extent than saturated fat. I assume he is going to eat whatever he fries are you saying an in Vitro study would be more relevant? If so why? And passing the smoke point of any oil Increases the rate of oxidation.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on January 12, 2013
at 10:27 PM

I didn't downvote either, but I do agree with Mscott. I do like the confidence in the response though. :)

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on January 12, 2013
at 09:15 PM

Oxidation in the study you posted is just referring the process of metabolizing fats into energy in the mitochondria, which is not a bad thing, unlike the oxidation of fatty acids by free radicals, which is accelerated by high heat and is definitely a bad thing.

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 09:19 PM

Well maybe I'll get two more downvotes so I can delete this answer and at least get a peer pressure badge, lol, I really thought this answered his question too. Thanks for clarifying,

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on January 12, 2013
at 09:02 PM

Okay, I'm thinking that he was asking about frying with olive oil vs saturated fat and how since they are kinda similar does one necessarily oxidize more than the other into the food and if so how would that effect his health.

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