Dietary Trans Fatty Acids

Author: maria marenco
Date: 02/02/2012



Trans fatty acids (TFA) are defined as unsaturated fatty acids containing one or more isolated (i.e. non-conjugated) double bonds in trans configuration.


The two major dietary sources for TFA include production via industrial hydrogenation of vegetable oils (partially hydrogenated vegetable oils, PHVO) from polyunsaturated fatty acids containing cis double bonds and through bacterial hydrogenation in the rumen.
Compared to unhydrogenated oils, PHVO containing industrial TFA (ITFA) are semi-solid, have a higher oxidative stability and a longer shelf life. Globally, PHVO are commonly used in processed food products such as margarines, deep-fried foods, bakery and instant products as well as in confectioneries.

Sources of naturally derived TFA (ruminant TFA, R-TFA) are milk, dairy products and meat.
PHVO in industrially processed foods can contain up to 50% TFA, mainly elaidic acid (trans-9-octadecenoic acid, t9-C18:1, t9) and t10-C18:1 (t10). In contrast, ruminant fats generally have low quantities of TFA (1–8%), with t11-C18:1 (vaccenic acid, t11) being the predominant trans C18:1 isomer.
Trans fatty acid isomers and the trans-9/trans-11 index in fat containing foods. 2011

elaidic acid

vaccenic acid


In Western Europe, including Scandinavia, the average daily intake of IP-TFA ( industrially produced TFA) has decreased during the recent decade due to societal pressure and a legislative ban, whereas the intake of RP-TFA has remained stable.

In spite of this decrease in many countries consumption >20 g of IP-TFA in a one-meal menu consisting of some popular foods is possible, even though the average intake of IP-TFA in these countries is low. Subgroups of the populations may therefore, on average, consume >5 g IP-TFA per day. This level of consumption is generally not possible for RP-TFA. A daily intake of 5 g TFA (primarily IP-TFA) is associated with a 29% increased risk of coronary heart disease.

Ruminant and industrially produced trans fatty acids: health aspects 2008


The dietary trans fatty acids are, for the most part, readily absorbed and incorporated into tissue lipids . The deposition of trans fatty acids in tissues may be selective. Thus adipose tissue and liver generally contain higher levels than other tissues. Minimum deposition of trans I 8: 1 occurs in the brain.

The trans fatty acids are converted to CoA esters and as such act as substrates for
acyl transferases and some desaturases. In general the trans 18: 1 seems to be treated
similarly to saturated fatty acid in the acylation of cholesterol and lysophosphatidylcholine.

Metabolism of trans fatty acids with emphasis on the effects of trans, trans-octadecadienoate on lipid composition, essential fatty acid, and prostaglandins: an overview.


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