Paleo Diet and Paleolithic Diet Questions & Answers

Question

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Hi there,

Since I eat quite a lot of lard I was a bit worried about it's high PUFA content of approx. 12%.

But then I vaguely remembered an article which said that lard and human adipose tissue have a similar composition. After a little bit of research I found this pdf:

http://www.pdiconnect.com/content/19/2/154.full.pdf

According to this study, the average human adipose tissue comprises of:

MUFA: ~65%
PUFA: ~12%
SFA: ~23%

This is indeed nearly the same PUFA content as in lard. Although various sources state that overall PUFA consumption should be limited to less than 4% of the complete caloric intake.

Now the question is:

I assume the human body stores it's fat exactly in the most healthy composition. Anything else wouldn't make any sense from an evolutionary stance. Therefore, anybody burning body fat would automatically have a PUFA consumption of ~12%.

Can I conclude that a PUFA intake from lard is optimal for humans? And that the 4%-PUFA-calories-a-day rule doesn't sustain?

EDIT:

I should have mentioned that the study is about the adipose tissue composition of dialysis patients on the island of Crete - anyway the control group has nearly the same values.

Thanks for the answers so far! So it seems that like grainfed animals' fat composition changes along with their diet, the ratios in human adipose tissue change as well with diet.

Has anybody a comparable study about human adipose tissue composition maybe in other cultures?

edited Jan 11 2012 at 6:21

asked Jan 10 2012 at 21:25

Thomy
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Our bodies don't simply rely on statistical probability to determine our tissue composition. Now, what the optimal amount of PUFA is in human tissues and what dietary inputs result in that optimum, I've seen no work on that. – Matt Jan 10 2012 at 23:29

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If your fat intake was 33% of your diet by calorie, and composed entirely of lard, that would make your PUFA intake 4%, yes? – Mitch Jan 10 2012 at 23:31

What Mitch said. Lard is not a horrible fat source, but it's not a great nutrient source. So it shouldn't be a huge percentage of your calories! – Beth-WeightMaven Jan 10 2012 at 23:44

Beth-WeightMaven · Accepted Answer · 2012-01-10 23:04:49Z UTC

I would not conclude that the PUFA content of adipose tissue of a specific population means that dietary PUFA in the same composition is optimal.

This diagram from Bill Lands' work (from a Stephan Guyenet blog post) shows that the amount of omega 6 in adipose tissue is directly related to the amount of dietary omega 3 and omega 6 ... and that the best bet is to keep omega 6 low, especially if you aren't getting sufficient omega 3.

Lands diagram

My take is that lard is fine as a fat source ... unless it turns out to be half or more of your calories. Or unless you're getting lots of omega 6s from other sources.

Travis Culp · Answer 2 · 2012-01-10 23:05:40Z UTC

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Your conclusions are way off. The composition of our fat depots reflects that of our diets. The link you have given only tells you what that composition is for dialysis patients on the island of Crete. The PUFA content of lard is too high, though you're likely leagues ahead of where someone who eats the SAD is.

answered Jan 10 2012 at 23:05

Travis Culp♦
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Travis, there were controls in that study! That said, I agree you cannot determine optimal dietary fat composition from that. – Beth-WeightMaven Jan 10 2012 at 23:10

thhq · Answer 3 · 2012-01-11 00:46:19Z UTC

Interesting how you can get confirmation of completely off-topic ideas by reading hacks. This discussion is further confirmation for me that the fat we eat becomes our stored fat untransformed by the liver. Into the bloodstream direct from the GI, and from there direct to the adipose if we are storing. A high carb/fat food (like a twinkie), eaten in excess so blood glucose is sky high, and we store whatever fat a twinkie contains. Same goes for pig lard, olive oil or beef tallow. If you are what you eat I'd rather be an animal than a twinkie.

Adipose tissue PUFA content

3 Answers