Incorporation of the dietary trans fatty acid (C18:1) into the serum lipids, the serum lipoproteins and adipose tissue

Abstract

Two diets, identical except for differences in trans and cis fatty acids, were fed to rabbits in order to evaluate the effects of dietary trans fatty acids on the fatty acid composition of serum lipids, lipoproteins and adipose tissue. The animals were first starved to deplete adipose tissue stores and then were red a diet containing 15% of the calories as C18:1 trans fatty acid (elaidic acid). A second group received a diet containing an equivalent amount of C18:1 cis fatty acid (oleic acid). A third group of animals, the control group, was fed only the baseline low fat rabbit chow. Dietary trans fatty acid was incorporated into all serum lipid and lipoprotein fractions and into the adipose tissue. In the serum the triglycerides contained the greatest amount of trans fatty acid followed by the phospholipids with cholesterol esters containing the least. The trans fatty acids of the phospholipids and cholesterol esters were distributed equally among the lipoprotein fractions, but the triglycerides of high density lipoproteins contained less trans fatty acids than did the triglycerides of other lipoproteins. Adipose tissue developed a high content of C18:1 trans fatty acid (21.7%), apparently at the expense of C18:1 cis fatty acid. In addition to the incorporation of C18:1 trans fatty acid, the content of other fatty acids, including C18:2 and the total of C18:1 cis and trans, was influenced by the substitution of dietary trans for cis fatty acids. The serum phospholipids of the trans-fed rabbits contained more C18:2 than the phospholipids of the cis-fed rabbits. The serum cholesterol esters of the trans-fed rabbits contained more C18:2 and a smaller total of C18:1 (cis puls trans) than the cholesterol esters of the cis-fed rabbits. These differences indicated that C18:1 trans fatty acid was not necessarily the metabolic equivalent of 18:1 cis fatty acid. These results suggested that dietary trans fatty acids which are contained in hydrogenated margarines, shortenings and oils of the human diet are readily incorporated into the lipids of the body including membranous structures such as lipoproteins.

Trans Fatty Acids: Properties, Benefits and Risks.

“…Beyond cardiovascular disease risk, another concern about trans fatty acids is theoretical at present. In both animal and human studies, dietary trans fatty acids have been determined to be digested, absorbed and incorporated into serum triglycerides, cholesterol esters, phospholipids, lipoproteins and adipose tissue, 10, [30][31][32] or platelets, 33) in the same way as natural cis isomers.…”

Effects of Weight Loss on the Fatty Acid Composition of Serum Lipids in Obese Women

“…The fact that they were not decreased after treatment suggests that enough of these fatty acids were mobilized and reached a pool available for the acvlating enzymes. In human depot fat co6 and to3 fatty acids have been found [2] as well as /ram-fatty acids when these were present in the pre viously consumed diet [18]. During very low calory dieting, there is a considerable mobili zation of fat from adipose tissue and most of the energy is provided for by fatty acid oxida tion.…”

SerumTrans-Fatty Acids Are Associated with Risk of Prostate Cancer in β-Carotene and Retinol Efficacy Trial

“…Trans-fatty acids are unsaturated fatty acids with at least one double bond in the trans configuration, formed during hydrogenation and vegetable oil processing, which are found primarily in fast foods, bakery products, packaged snacks, and margarines (8,9). Trans-fatty acids resemble saturated fatty acids in their biophysical properties but are not as extensively metabolized, and thus serum trans-fatty acid levels reflect dietary intake (10)(11)(12). Here we examine the associations of specific trans-fatty acids, measured in serum phospholipids, with prostate cancer risk.…”