Unsaturated fatty acids increased HDL cholesterol less than did SFAs. As a result, the replacement of 1% of energy in the form of
SFAs with an equal percentage in the form of cis MUFAs is predicted
to lower HDL-cholesterol concentrations by 0.002 mmol/L.
A similar decrease is expected when 1% of energy in the form of
MUFAs is replaced with an equal percentage in the form of
PUFAs. These effects, however, are small compared with those of
replacement of carbohydrates with any of the 3 classes of fatty
acids. Replacement of carbohydrates with any class of fatty acids
decreased fasting serum triacylglycerol concentrations (Table 1).
The effect was slightly but not significantly larger for PUFAs than
for other fatty acids. This contrasts with the powerful triacylglycerol-
lowering effect of n3 PUFAs from fish (12), which is evidently
not shared by linoleic acid, the major n6 PUFA.
Replacement of carbohydrates with SFAs did not change
apo B concentrations. The cis unsaturated fatty acids, however,
decreased apo B, and this effect was slightly stronger for PUFAs.