Dietary fats, lipoprotein, metabolism

Catalytic hydrogenation of vegetable oils is widely used to form harder fats and to decrease the content of polyunsaturated fatty acyl groups. The products have a greatly increased resistance to rancidity. However, they also contain fats with trans double bonds as well as isomers with double bonds in unusual positions.251 253 Such compounds may interfere with normal fatty acid metabolism and also appear to affect serum lipoprotein levels adversely. Trans fatty acids are present in some foods. One hundred grams of butter contain 4-8 g, but hydrogenated fats often contain much more. It has been estimated that in the United States trans fatty acids account for 6-8% of total dietary fat.253... 

Kris-Etherton, P.M., Binkoski, A.E., Zhao, G., Coval, S.M., Clemmer, K.F., Hecker, K.D., Jacques, H., Etherton, T.D. 2002. Dietary fat assessing the evidence in support of a moderate-fat diet the benchmark based on lipoprotein metabolism. Proc. Nutr. Soc. 61, 287-298. 

Nicolosi, R. J. (1997). Dietary fat saturation effects on low-density lipoprotein concentrations and metabolism in various animal models. Am.. Clin. Nutr. 65,1617S-1627S. 

Ordovas JM, Corella D, Demissie S, et al.. Dietary fat intake determines the effect of a common polymorphism in the hepatic lipase gene promoter on high-density lipoprotein metabolism evidence of a strong dose effect in this gene-nutrient interaction in the Framingham Study, Circulation, Oct 29 2002 106(18) 2315-2321. 

Liver is a central organ affecting lipid and lipoprotein metabolism. Dietary CLA has been reported to increase hepatic lipid contents in mice, concomitant with a decrease in body fat mass (6-8), although it is not clear whether this is the case for other experimental animals and humans. Hence,... 

Nonetheless, the debate over what constitutes the "ideal" fat is controversial, since it uses the term saturated fat without distinguishing individual SFA. In this sense, even a cursory analysis of some of the so-called saturated fats (e.g., palm oil, lard, tallow, butter, coconut oil) reveals that they have distinct profiles and empirically exert different metabolic effects. Accordingly, research in recent years has shifted toward elucidating the effects of specific dietary fatty acids in TAG, as opposed to specific classes of fats, on plasma lipids and lipoprotein metabolism [141]. 

In principle, vitamin E deficiency can resulf from insufficient dietary intake, malabsorption or excessive consumption in case of oxidative stress in biomembranes. While the former is virtually nonexistent in Western society, the impaired ability to utilize dietary fats may create hypovitaminosis E in certain risk populations, e.g., patients with pancreatic dysfunction or defects in lipoprotein metabolism and particularly in premature infants. Deficiency disorders in the latter include bronchopulmonary dysplasia, retrolental fibroplasia (retinopathy), intraventricular hemorrhage, hemolytic anemia, and neuromuscular anomalies. 

The relationship between dietary fats and cardiovascular disease (CVD), especially CHD, has been extensively investigated, with strong and consistent associations emerging from a wide body of evidence accrued from animal experiments, as well as observational studies, clinical trials, and metabolic studies conducted in diverse human populations. This relationship was initially considered to be mediated mainly through the atherogenic effects of plasma lipids (total cholesterol, lipoprotein fractions, and triglycerides). The effects of dietary fats on... 

Most aspects t>f carbohydrate nutrition are simpler than those of other nutrients, (For example, fat nutrition is complicated by the fact that the metabolism of fats requires bile salts to maintain solubility during digestion and lipoproteins and albumin during distribution in the body.) On the other hand, the nutrition of the carbohydrates that take the form of dietary fibers is very complicated. This complexity . > due to the fact that they arc metabolized by enzymes of the gut microflora. 

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