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.
asked byMike_T_1 (9402)
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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.