Medium-chain fatty* acids cholesterol effects

It is important to bear in mind when discussing the effect of dairy fat in association to heart disease that dairy products contain many different saturated fatty acids that do not exert the same biological response in terms of, for example, cholesterol levels. The saturated fatty acids in milk fat include shorter and medium chain fatty acids (2 0-10 0), lauric acid (12 0), myristic acid (14 0), palmitic acid (16 0), and stearic acid (18 0). Other fatty acids in milk fat are oleic acid (18 1) and linoleic acid (18 2n-6) as indicated in Table 1.2. 

Medium-chain fatty acids are saturated fatty acids because of the relatively shorter hydrocarbon chain, which does not facilitate unsaturation. The safety of medium-chain triacylglycerol (MCTs) in dietary oil has been debated, and associated effects on cholesterol metabolism remain unclear. Although some studies have shown that... 

Ikeda, I., Tomari, Y., Sugano, M., Watanabe, S., and Nagata, J. 1991. Lymphatic absorption of structured glycerolipids containing medium-chain fatty acids and linoleic acid, and their effect on cholesterol absorption in rats. Lipids 26 369-373. 

Since then, there have been numerous studies that investigated the effect of different types and amounts of fat, individual fatty acids and other dietary components on plasma cholesterol level. It is now realized that all saturated fatty acids do not elevate plasma cholesterol levels to the same extent. The short-chain fatty acids, butyric (C4 o), caproic (C6 o), caprylic (Cs o) the medium-chain capric (Cio o) and stearic (Ci8 o) acids,... 

It is now known that not all saturated fatty acids are equally hypercholesterole-mic. For example, medium-chain saturated fatty acids of carbon length 8-10, as well as stearic acid (18 0), have little or no effect on serum cholesterol concentrations. In contrast, evidence indicates that palmitic acid (16 0), the principle fatty acid in most diets, can increase serum cholesterol concentrations in humans. However, in normocholesterolemic humans, dietary palmitic and oleic acids have been shown to exert similar effects on serum cholesterol, suggesting that only humans or animal species sensitive to dietary cholesterol and selected fats ( hyperresponders ) may exhibit significant changes in semm cholesterol in response to dietary fat intake. Myristic acid (14 0) and, to a lesser extent, lauric acid (12 0), which are relatively high in coconut oil, both can raise serum cholesterol and LDL-cholesterol levels. Overall, it is not clear why humans respond so differently to cholesterol or... 

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