The Diversity of Health Effects of Individual trans Fatty Acid Isomers

Abstract

There are multiple adverse effects of trans fatty acids (TFA) that are produced by partial hydrogenation (i.e., manufactured TFA), on CVD, blood lipids, inflammation, oxidative stress, endothelial health, body weight, insulin sensitivity, and cancer. It is not yet clear how specific TFA isomers vary in their biological activity and mechanisms of action. There is evidence of health benefits on some of the endpoints that have been studied for some animal TFA isomers, such as conjugated linoleic acid; however, these are not a major TFA source in the diet. Future research will bring clarity to our understanding of the biological effects of the individual TFA isomers. At this point, it is not possible to plan diets that emphasize individual TFA from animal sources at levels that would be expected to have significant health effects. Due to the multiple adverse effects of manufactured TFA, numerous agencies and governing bodies recommend limiting TFA in the diet and reducing TFA in the food supply. These initiatives and regulations, along with potential TFA alternatives, are presented herein.

Intake of ruminant trans fatty acids and changes in body weight and waist circumference

“…Moreover, vaccenic acid is a precursor of CLA and dairy is the main dietary source of CLA, which has been shown to reduce body weight and fat depositions in several animal studies. 5,6 In agreement with this, a cross-sectional study of TFA in adipose tissue suggested that individual TFA isomers may have divergent effects on adiposity. 33 For fatty acids not synthesised endogenously in humans, such as TFA, the proportions in adipose tissue tend to correlate well with dietary intake and reflect the dietary intake of fatty acids during the previous couple of years.…”

“…3,4 Several animal studies have found that feeding CLA reduces body weight and fat depositions, but the results from human studies have been inconsistent. 5,6 Studies have suggested that industrial TFA (I-TFA) and R-TFA may elicit different biological effects. 7 It has been hypothesised that R-TFA, or some specific TFA isomers, may elicit health benefits, but the evidence is weak and more studies are needed.…”

“…7 It has been hypothesised that R-TFA, or some specific TFA isomers, may elicit health benefits, but the evidence is weak and more studies are needed. 5,8 I-TFA intake in the Danish population has decreased from 2.2 g/day in 1992 to 0.35 g/day in 1999. 9 In 2004, Denmark imposed a restriction on the content of I-TFA in margarines and shortenings.…”

F2-isoprostanes are correlated with trans fatty acids in the plasma of pregnant women

“…Consumption of iTFA has adverse effects on cardiovascular health by altering blood lipid profile (increase of total to HDL cholesterol ratio, increase in LDL-cholesterol, decrease in HDL-cholesterol), by modifying apolipoprotein levels, and by promoting systemic inflammation as well as endothelial dysfunction [4][5][6][7][8][9][10]. The various isomers of TFA may have different biological and physiological effects as a function of the length of the carbon chain, the number and the position of the carbon-carbon double bonds.…”

Differential impact of milk fatty acid profiles on cardiovascular risk biomarkers in healthy men and women

“…In this respect, dietary fatty acids represent key factors having a significant impact on health, especially on CVD. Specific effects of clusters or isolated fatty acids have been extensively studied, with a particular attention paid to saturated fatty acids (SFAs) and trans fatty acids (TFAs) (Katan et al, 1995;Hu et al, 1997;Ascherio et al, 1999;Gebauer et al, 2007). Reports from different health authorities and agencies recommend a reduction of SFA and TFA intake (Stender and Dyerberg, 2003;Scientific Panel on Dietetic Products, 2004;Afssa, 2005).…”