Trans fatty acids

Industrially hardened fatty acids – they raise LDL, lower HDL and are associated in studies with raised inflammatory markers.

What trans fatty acids do in the body

Trans fatty acids are unsaturated fatty acids in which at least one double bond lies in the straight trans position instead of the naturally usual, kinked cis position. Their chain therefore resembles that of a saturated fatty acid. They arise during the industrial partial hydrogenation of vegetable oils – above all elaidic acid –, when oils are heated strongly, and naturally in small amounts in the rumen of ruminants, which is why milk and meat contain some vaccenic acid. The body builds trans fatty acids into membrane phospholipids, cholesterol esters and triglycerides like other fatty acids. No task for which it needs them is known; in the membranes they make the lipid layer stiffer.

Low trans fatty acids – what does it mean?

A low value shows that only few trans fatty acids are built into the membranes of red blood cells. Because the body does not need them for any known task, low values do not lead to a deficiency; their positions in the membranes are taken by cis fatty acids, which keep the membrane flexible. Since industrially hydrogenated fats have been legally limited in the EU, foods with high contents are found less often. A small share of natural trans fatty acids from milk and meat is usually detectable even when overall values are low.

High trans fatty acids – what happens in the body?

Industrial trans fatty acids alter fat metabolism at several points: they increase the activity of cholesteryl ester transfer protein (CETP), which shifts cholesterol from HDL to LDL and VLDL particles, so that LDL rises and HDL falls; they also raise lipoprotein(a) and triglycerides. In the membranes of vascular cells they make the lipid layer stiffer and promote inflammatory signals – in studies, messengers such as TNF-alpha and interleukin-6 as well as CRP rose. The inner vessel wall widens less well. In addition, trans fatty acids interfere with the desaturases that form long-chain omega-3 and omega-6 fatty acids. In observational studies, high values were associated with cardiovascular disease.

The interpretation is given in your report.