Tropical Oils: A better saturated fat?

Wednesday, September 23, 2009 15:22
Comments Off on Tropical Oils: A better saturated fat?

Shelly posted the following comment on a recent post on dietary fats:

"I've been reading some
information that says coconut oil does not cause plaque build-up like other saturated fats because it is a medium-chain fatty acid, which apparently means it is
digested more like a carb and doesn't have a chance to become plaque.
I'd like to find more sources of this information, just to build some
confidence. (When I relay this information about coconut, people look at
me as though I'm from Mars.)"

Before I had a chance to respond, Dave posted a comment in response to Shelly's question:

"Short-chain fatty acids do take a different route than
most fats. Most fats we eat are packaged up by the small intestine in
large lipo-protein molecules called chylomicrons, which take a leisurely
route through the lymphatic system before being dumped into circulation
several hours after a meal. Short-chain fatty acids, by contrast, get
a ride straight to the liver. The liver utilizes mostly fats for
energy, so this probably frees up other energy sources for the body
(the liver has high energy requirements), giving a quick-energy boost
much like carbohydrates."

I love it when you guys do my work for me!  All I would add to Dave's little seminar on fatty acid metabolism is that the upshot of this is still largely hypothetical.  It might seem that medium and short chain fatty acids would be less likely to be stored as fat and/or form arterial plaques because they are metabolized differently. But there is very little research on what effect replacing other dietary fats with tropical fats has on weight or heart disease risk. (What research there is is contradictory.)

What's the take-home?

Shelly's question seems pretty straight-forward but there are actually a number of issues entwined in the tropical oil question. Here's my take on a few of them:

1. The role of dietary fat in obesity has been over-estimated in the past.
But I think the pendulum may now have swung a bit too far in the other
direction.The role of dietary fat in obesity is now being underestimated in some quarters.  In other words: Fat doesn't make you fat–but it probably doesn't make you thin either.

2. The role of dietary fat (and saturated fat in particular) in heart disease has probably been over-estimated. See also Steve Parker's post "Diet-Heart Disease Hypothesis: RIP".  My own pet theory is that the effect of dietary fats on health depends a lot on the quantity and quality of carbohydrates in the diet. Any study that fails to look at that interaction (which is most of them) is likely to reach unreliable conclusions.

3. Tropical oils are probably no more dangerous than animal saturated fats–which, as I noted above may not be as dangerous as we thought. 

4. Unrefined (extra virgin) tropical oils also contain some valuable antioxidants and phytonutrients.

5. Buyer beware: Many of the health claims being made for coconut oil these days are unsubstantiated and/or exaggerated. (See also my recent podcast on coconut oil.)

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