Complementary Alternative Cardiovascular Medicine
Complementary Alternative Cardiovascular Medicine
Complementary Alternative Cardiovascular Medicine
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76 <strong>Alternative</strong> <strong>Cardiovascular</strong> <strong>Medicine</strong><br />
amount of dietary cholesterol. The original equations developed by Keys<br />
et al. (5) and Hegsted et al. (6), reported by both in 1965, and more<br />
recently by Mensink and Katan (7), Hegsted et al. (8), and Clarke et al.<br />
(9), demonstrated that saturated fat was hypercholesterolemic, whereas<br />
PUFA lowered blood cholesterol levels. Saturated fat was twice as potent<br />
in raising blood cholesterol levels as PUFA was in lowering them. Specifically,<br />
the blood cholesterol predictive equations demonstrated that for<br />
each 1% increase in saturated fatty acids (SFAs), blood cholesterol<br />
increased 1.5 to 2.7 mg/dL. The investigators reported that MUFA had<br />
a neutral effect and that dietary cholesterol raised the blood cholesterol<br />
level but less so than saturated fat. A summary of the effect of SFA on<br />
LDL cholesterol is shown in Fig. 1.<br />
TRANS FATTY ACIDS<br />
Trans fatty acids are unsaturated fatty acids with one or more double<br />
bonds in the trans configuration. The resulting extended fatty acid chain<br />
is similar to saturated fat. Several epidemiologic studies have reported<br />
a positive relationship between trans fatty acid intake and both incidence<br />
of CHD and risk factors for CHD, notably lipids and lipoproteins (10–12).<br />
Numerous early controlled feeding studies reported that hydrogenated<br />
fats elicited a blood cholesterol response that was intermediate to<br />
that observed for unhydrogenated oils and saturated fats (reviewed in<br />
ref. 13). More recently, studies have been conducted to evaluate the<br />
plasma lipid and lipoprotein effects of trans fatty acids. These studies<br />
have consistently shown that trans fatty acids increase plasma total and<br />
LDL cholesterol relative to unsaturated fatty acids (14–16). Trans fatty<br />
acids elicit comparable cholesterol-raising effects vs SFA. In addition,<br />
trans fatty acids do not increase high-density lipoprotein (HDL) cholesterol<br />
as does SFA (17), resulting in a lower HDL cholesterol and a<br />
worsening of the LDL:HDL ratio which, in turn, increases CHD risk (see<br />
Fig. 2) (18).<br />
DIETARY CHOLESTEROL<br />
Numerous controlled clinical studies have shown a positive linear association<br />
between dietary cholesterol and LDL cholesterol. Consequently,<br />
because of an increase in LDL cholesterol, there is an increase in CHD risk.<br />
However, the LDL cholesterol-raising effect of dietary cholesterol is less<br />
than that of SFA. An increase of 100 mg/d of dietary cholesterol is predicted<br />
to result in a 0.5 to 1 mmol/L increase in total serum cholesterol,<br />
resulting in a 1% to 2% increase in CHD risk (see Fig. 3) (1).