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