Unbound Free Fatty Acids
Long chain free fatty acids are essential for life. They are the major source of energy. Free fatty acids are generated by fat cells and are then transferred to blood plasma.
Most of the free fatty acid is carried through the plasma bound to serum albumin. Only a small fraction of the total amount of free fatty acid ends up in the water part of the plasma. These molecules are known as the unbound free fatty acids. (Note: FFA concentrations are the same in serum or plasma and we use the term plasma FFAu to mean serum or plasma.)
Athough essential for life, elevated levels of free fatty acids can be deleterious to a wide variety of cellular functions. Consequently, the body maintains plasma levels of free fatty acids within a narrow range, exceeding the upper limit of this range only in pathological conditions.
Unbound, rather than total, free fatty acid levels provide the most sensitive indicator of the pathologic state because FFAu interact directly with cells and because the level of FFAu increases exponentially with a linear rise in total free fatty acids.
Click on the link
to view a
of unbound free
acids (FFAu) and their relationship to total plasma FFA and albumin.
The concentration of these aqueous phase molecules (FFAu) is buffered
by the FFA/albumin complexes.
rather than total
free fatty acid levels
provide the most
sensitive indicator of
the pathologic state