ruminant fatty acid distribution

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I thought this might be of interest to some of you.

The following is a description of *why* tissue in ruminant and hoofed animal

*extremities* are higher in PUFA than internal organs. This could possibly

explain why the Cordain (and colleagues) studies found high PUFA

concentrations in the tissues they tested, although I'm not sure

specifically what tissue they tested (if it were primarily extremities).

Does anyone have a copy of Cordain's study? I'd really love to read the full

article

The gradient from higher PUFA in cooler regions to lower PUFA in warmer

regions *of the body* reminds me of the same gradient of *the planet

itself* - plants in cooler regions have higher PUFA content than those

closer to the equator. This makes sense because the intense light and heat

close to the equator would oxidize plant lipids in that region. That would

account for why highly saturated oils such as coconut and palm grow in

equatorial regions.

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From " The Fats of Life " by C.M. Pond.

Local Adaptation

Even in tropical mammals, the skin surface, and often whole appendages such

as ears, tails, legs, hooves and paws, are cooler than the core body

temperature while the animal is at rest. In cold climates, these appendages

may be as cool as 5 degrees Celsius (about the same as a refrigerator),

while the brain and viscera are at 38 degrees Celsius. The mixtures of

triacylglycerols of the composition usually found at internal adipose depots

would solidify at the temperatures of the limbs. For the reasons to be

explained in Chapter 4, ruminant triacylglycerols necessarily contain a high

proportion of saturated fatty acids, but the composition of fatty acids in

lipids located in cool appendages is nonetheless adapted to the temperatures

at which they are maintained.

[suze here: this is why we have to know which depots are tested when claims

are made that FA composition of diet is reflected in tissue.]

Site-specific differences in the composition of triacylglycerol fatty acids

in adipose tissue were studied in Svalbard reindeer during the winter when

the average temperature was around -20 degrees Celsius. These small reindeer

have thicker fur than other deer, and it extends further than usual over

their legs and hooves, making them look like a cross between a sheep and a

shire horse. A greater proportion of unsaturated fatty acids was found in

triacylglycerols in the adipose tissue near the skin than in samples from

the inner side of the same depot. There was a similar gradient in

composition of triaclglycerol fatty acids in the fatty bone marrow from hip

or should to hooves that makes it clear that the feet are normally cool,

much cooler than the internal organs. The unsaturated fatty acids help to

keep the mixtures of triaclglycerols fluid, and hence metabolically usable,

at lower temperatures. How such selective accumulations (or, conversely,

selective release) of certain fatty acids could be achieved is described in

Chapter 4.

The distribution of triacylglycerols of different fatty acid composition

follows a similar pattern in other hoofed animals that live in cool

climates. The special flavour and properties of neat's foot oils ('neat' is

the Anglo-Saxon word for cattle) have been known and exploited since the

Middle Ages, and probably earlier. This material, extracted by boiling the

hooves of slaughtered cattle or horses, is liquid at room temperature while

suet and other beef fats are solids, because it contains much more oleic

acid and fewer saturated fatty acids, especially stearic and myristic acids,

than triacylglycerols in adipose tissue around the kidneys, between the

muscles or in other warm parts of the body. " (pp. 91-92)

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Suze Fisher

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