Food Lipids: Chemistry, Nutrition, and Biotechnology

McGandy and coworkers [8] have carefully compared the effects of MCFAs,
mainly capric acid, on plasma total and LDL cholesterol levels. Eighteen physically
healthy men were fed several diets, each for 4 weeks. Diets contained several lowfat
food items to which the experimental fats were added. It was shown that modest
amounts of MCFAs in the diet have comparable effects on the plasma total and LDL
cholesterol and on triacylglycerols concentrations as have carbohydrates. However,
large amounts of MCFAs increased triacylglycerol concentrations. Recent results of
Cater et al. [9] suggested that a mixture of MCFAs slightly decreases LDL cholesterol
concentrations relative to palmitic acid but increases LDL cholesterol relative to oleic
acid (Fig. 2).
b. Lauric and Myristic Acids. Palm kernel oil, coconut oil, and dairy fat are
rich in lauric acid but also contain relatively high amounts of myristic acid. Therefore,
it is hardly possible to study the specific effects of these two saturated fatty
acids on plasma lipoproteins with natural fats. For example, a diet enriched in palm
kernel oil will contain high amounts of both lauric and myristic acids, and it will
subsequently be impossible to ascribe the effects on the plasma lipoprotein profile
to lauric or myristic acids. To circumvent this problem, most studies have used
synthetic fats to examine the cholesterolemic effects of these two saturated fatty
acids. In this way, a fat with any desired fatty acid composition can be made. For
example, when one interesterifies trilaureate with a high oleic acid sunflower oil, the
result will be a high lauric acid fat without any myristic acid.
Denke and Grundy [10] compared the effects on plasma lipoproteins of lauric
acid with those of palmitic acid and oleic acid. Three different liquid formula diets,
which differed only in the type of fat used, were fed for 3 weeks in random order
to 14 men. It was concluded that lauric acid raised plasma total and LDL concentrations
as compared with oleic acid, but to a lesser extent than the palmitic acid
Figure 2 Effects of medium chain triacylglycerols and palmitic acid on plasma total, LDL
cholesterol, HDL cholesterol, and triacylglycerol concentrations relative to those of cismonounsaturated
fatty acids (oleic acid). Nine men received three mixed natural diets, each
for 3 weeks, in random order. The composition of the diets was identical, except for 43% of
daily energy intake, which was provided as medium chain triacylglycerols (C8:0 and C10:0),
palmitic acid (C16:0), or oleic acid (cis-C18:1) [9].
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