Browsing the USDA database, I found some interesting things.
I was interested in the fatty acid content of various fats,
especially arachidonic acid, stearic acid, myristic acid, and
palmitic acid.

First, mutton tallow.  It has no arachidonic acid, but has 19.5g
of stearic per 100g, as well as 21.5g palmitic and 3.8g myristic.
It also contains 40.6g of monounsaturated fats.

Beef tallow also has no arachidonic acid, but has 18.9g stearic,
24.9g palmitic, and 3.7 myristic, so it is quite similar to
mutton tallow.  41.8g monounsaturated.

Chicken fat, on the other hand, has .1g arachidonic, only 6g
stearic, 21.6g palmitic, and .9g myristic.  44.7g
monounsaturated.

Now let's look at the values for actual beef, "composite of
trimmed retail cuts."  Here we find .30g arachidonic, only 2.5g
stearic, 5.2g palmitic, and .680 myristic.  9.2g monounsaturated.

It is to be expected that the total fat counts of beef will be
less than the others, but it is interesting to see how the ratios
change.  In particular, the ratio of stearic acid to palmitic
plus myristic is much higher in the plain fats than in the beef
cuts.  This is presumably due to the muscle fat content.  In all
cases the ratio of monounsaturated fats to total fats is about
40-45%

There is evidence that stearic acid is beneficial, in terms of
cardiovascular effects.  Palmitic and myristic acid appear to be
hypercholesterolemic; palmitic is especially so in the presence
of dietary cholesterol.

An interesting hypothesis that is suggested by all this is that
pemmican, made with tallow, is preferable to retail beef, since
it maintains more favorable fatty acid ratios.

Todd Moody
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