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Tuesday, April 13, 2010

Fatty Acid Contents of Foods: Beef Fat vs. Seal Oil

Another random listing from fatty acid compositions at www.nutritiondata.com


This post was precipitated by the oft cited Inuit as an example of the benefit of an almost all "meat", very high fat diet.  I've noticed that many of those practicing this version of a "Paleolithic" diet, tend to consume a lot of beef and rarely eat even the fish which are another staple of the Inuit diet.  So I decided to compare beef fat to that in seal oil.  The contrasts are quite stark!!


Beef fat is roughly 50% saturated fat vs. just over 10% for the seal oil.  Palmitic acid makes up around half of the sat fat in both.  Interestingly, the seal oil has 15 and 17C chain length sat fats.   


The MUFA content is roughly comparable at around 47% with a slight edge to the seal oil.  Most in the beef is oleic acid (18C) while the predominant acids in the seal oil are both oleic and palmitoleic (16C).  Again of note is the odd chain length acids.


The PUFA content of beef is a paltry less than 4%, while it is 33% of seal oil!   But that’s not all on the PUFA front – the Omega 6:Omega 3 ratio for beef fat is more than 5:1 … for seal oil it’s 1:26 – yes, that’s right more than 25:1 in favor of the Omega 3’s!!   Ounce for ounce, one gets 48X the dose of Omega 3’s from the seal oil vs. beef fat.  This is astounding.  The almost 8g of Omega 3’s is a huge dose if one were to try to get that from supplements – and that’s for only 1oz (~2T) of seal oil. 

The quality of the essential fatty acids in seal oil is also of note:
   2719 mg DPA, 1572 mg DPA and 3485 mg DHA

So … what of grass-fed beef?  I can’t find an analysis for grass-fed beef tallow, but, again from nutritiondata.com, the fatty acid breakdown of the fat in grass-fed beef is not impressive.  The PUFA content is still less than 4% of total fat and insignificantly more (3.94% vs. 3.93% for the commercial beef tallow).  The Omega 6:Omega 3 ratio?  It is improved slightly – from the 5.17:1 for the commercial to 4.85:1 – hardly approaching the “ideal” of 1-2:1 – such ratios can only be attained through marine and certain non-animal sources, or by eating brains and such.   Oh but surely nutritiondata.com is a biased thus incorrect source.  I suspected such, but when looking at every source I could find – many champions of the burgeoning grass-fed beef market – for more than an hour one day, I could find no other source even as specific as this one.  Claims of better O6:O3 ratio abound – but no specifics, leading me to believe that the “gains” are modest at best as seen in nutritiondata’s numbers.  What of absolute “dose”?  This probably comes out in favor of the commercial beef that is higher in total fat content.

Bottom line, beef fat is a poor source of PUFA’s in general and Omega 3 fatty acids in particular.  And it does not have a favorable O6:O3 ratio.  Sure, ~5:1 is better than the ratios for most seed oils, but the beef consuming VLC or ZC’er is not getting a significant dose of O3, nor is the O6:O3 ratio of ~5 favorable.

I believe the Inuit is a poor model to point compared to what many consume in modern high fat diets because it bears little resemblance to these diets.




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