One of the mainstays of, ahem, “alternative” approaches to explaining cardiovascular disease risk is the claim that unsaturated fatty acids are more rapidly oxidized than saturated fatty acids, thus forming oxidized LDL cholesterol.

After all, the double bond in unsaturated fatty acid should lend itself to reacting with oxygen much more readily, thus being oxidized.

But is this true? Read ’em and weep, my friends. It ain’t. Two studies in fact suggest the same result: monounsaturated fat, such as that found in olive oil, actually increases resistance of LDL particles to oxidation as compared to saturated fat, such as that found in butter and other animal products.


The two studies? *drum roll*

Before continuing, let us take a look at a graph from the first study:

The wash-in diet is high in saturated fat, as can be seen from the below table:

Anyway, what’s the practical takeaway here?

Not only does saturated fat increase blood levels of LDL cholesterol (believed by most lipidologists to be a major driver of cardiovascular disease risk) but saturated fat also increases oxidized LDL cholesterol (believed by a minority of lipidologists and the majority of low-carb proponents to be the reason that LDL cholesterol causes heart disease). Saturated fat loses both ways. So, plant fats such as those in olive oil may be superior not only for reducing LDL cholesterol levels but also oxidized LDL cholesterol levels, the purported cause of cardiovascular disease even according to proponents of high intakes of saturated fat. In other words, those who advocate the theory that oxidized LDL and not total LDL is most important for cardiovascular disease should in fact be recommending olive oil over animal fats. And indeed, this recommendation seem to be what the current evidence would overwhelmingly point to–even according to Gary Taubes.

TLDR: Olive oil. Not butter.

Two more theoretical/scientific lessons.

One. While mechanistic reasoning is appealing–that is, thinking in terms of what might happen given the molecules in question–once you introduce complex biological systems into the equation, the outcomes can actually reverse from what might otherwise be anticipated. This is because other mechanisms, not previously considered, might actually have a greater impact on the outcome in question than the first-considered mechanism.

Two. Check the human studies for evidence of your hypothesis! The claim that unsaturated fat oxidizes more readily than saturated fat constantly makes the rounds around Internet nutrition circles–probably because of some of the earlier claims of the likes of Chris Masterjohn and others. But little does anyone check what the actual studies say. These two studies are from 1996 and 2002. That is, they are 24 and 18 years old, respectively! Egads!

“Will not use mechanistic reasoning alone.”
“Will check for human studies conducted addressing my question.”
“Will not use mechanistic reasoning alone.”
“Will check for human studies conducted addressing my question.”
“Will not use mechanistic reasoning alone.”
“Will check for human studies conducted addressing my question.”

Say them 10 more times.

And go forth. And spread nutrition science goodness to the world.


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