Complementary Alternative Cardiovascular Medicine

80 Alternative Cardiovascular Medicine
addition, a cross-sectional study reported an inverse association between
linoleic acid intake and CHD prevalence (25). The epidemiologic studies
showing a beneficial effect of omega-6 PUFA are supportive of
earlier clinical trials conducted to assess the effects of diets high in
PUFA but low in SFA and cholesterol on the risk of coronary morbidity
and mortality. Several major primary and secondary prevention trials
(26–29) were conducted to assess the effects of diets that provided 35–
39% of calories from total fat, 13–21% of calories from PUFA, and
approx 9% of calories from SFA and were low in cholesterol. The studies
were the first to show that a high-PUFA diet decreased serum cholesterol
levels markedly (13–16%), which was associated with a concurrent
decrease in CVD events. Although initially these findings sparked much
interest in the use of a high-PUFA diet to decrease CVD risk, enthusiasm
diminished because of limited data from long-term studies and the scarcity
of data from population groups who followed this diet habitually.
Questions were also raised about the role of PUFA in oxidation reactions,
risk of cancer, and some evidence that high intakes of PUFA can
inhibit formation of long-chain omega-3 PUFA from ALA (1).
Because of the lack of population data about the safety of high-PUFA
diets, interest was sparked in assessing the role of MUFA in a blood
cholesterol-lowering diet (i.e., low in SFA and cholesterol) as a substitute
for SFA calories. Based on a significant database of experimental studies
with diets that can be consumed habitually, although PUFA do have a
greater total and LDL cholesterol-lowering effect vs MUFA, the differences
are small. Thus, for practical purposes, MUFA or PUFA elicit blood
cholesterol-lowering effects that are quite similar when incorporated in a
diet that meets current recommendations (30).
There are emerging CVD risk factors that play a role in atherogenesis
and inflammation. One area of great interest relates to the regulatory
effects that fatty acids have on expression of genes involved in leukocyte
adhesion molecule synthesis. Omega-3 fatty acids inhibit endothelial
activation, and omega-6 fatty acids have a less potent inhibitory effect,
albeit more so than MUFA (31). In summary, PUFAs have
cardioprotective effects that are mediated by multiple mechanisms that
extend beyond the risk reduction conferred by decreases in total and
LDL cholesterol.
Omega-3 Fatty Acids
The primary plant-derived omega-3 fatty acid is ALA and the marinederived
omega-3 fatty acids are EPA, C20:5n-3 and DHA C22:6n-3.
There is an impressive database from epidemiologic studies and randomized
controlled clinical trials that omega-3 fatty acids have