Why Should We Eat More Salmon?
are elements in the blood that initiate blood clotting and tissue repair by
releasing clotting factors and platelet-derived growth factor (PDGF).
Turbulence in the bloodstream may cause platelets to rupture. Fat deposits and
bifurcations of arteries lead to such turbulence, so platelets and PDGF are
implicated in blood clotting and growth of atherosclerotic plaque. Furthermore,
the anaerobic conditions that exist under a large plaque deposit may lead to
weakness and dead cells in the arterial wall, aggravating the problem.
cultures that depend on fish as a major food source, includ-ing some Eskimo
tribes, very little heart disease is diagnosed, even though people in these
groups eat high-fat diets and have high levels of blood cholesterol. Analysis
of the their diet led to the discovery that certain highly unsaturated fatty
acids are found in the oils of fish and diving mammals. One class of these
fatty acids is called omega-3 (v3), an example of which is
eicosapentenoic acid (EPA).
presence of a double bond at the third carbon atom from the end of the
hydrocarbon tail. The omega system of nomenclature is based on numbering the
double bonds from the last carbon in the fatty acid instead of the carbonyl
group [the delta (D) system]. Omega is the last letter in the Greek alphabet.
omega-3 fatty acids inhibit the formation of certain prostaglandins and
thromboxane A, which is similar in structure to prostaglandins. Thromboxane
released by ruptured arteries causes other platelets to clump in the immediate
area and to increase the size of the blood clot. Any disruption in thrombox-ane
synthesis results in a lower tendency to form blood clots and, thus, in a lower
potential for artery damage.
also inhibits prostaglandin synthesis, although it is less potent than EPA.
Aspirin inhibits the synthesis of the pros-taglandins responsible for
inflammation and the perception of pain. Aspirin has been implicated in
reducing the incidence of heart disease, probably by a mechanism similar to
that of EPA. However, people who are being treated with blood thinners or who
are prone to easy bleeding should not take aspirin.