Ruminant and industrial trans-fatty acids consumption and cardiometabolic risk markers: A systematic review

The development of cardiometabolic diseases is related to conditions such as obesity, abdominal fat, insulin resistance, diabetes mellitus, elevated blood pressure and changes in lipid profile. The whole of Trans Fatty Acid (TFA) intake is associated with the increase of cardiometabolic risk factors. There are two main sources of TFA, the ruminant TFA (rTFA) which are produced by biohydrogenation in animal's rumen, and the industrial TFA (iTFA), produced by hydrogenation of vegetable oils, the individual effect of each group is still controversial. The aim of this study was to analyze the effect of industrially and ruminants TFA intake on cardiometabolic risk in adults. It was carried out a systematic search of the literature in October 2019 and two independent authors selected and extracted data from articles. After the selection process, nine clinical trials were included, and summary tables were constructed to present data for all outcomes. The results showed that both sources of TFA can increase cardiometabolic risk parameters, especially lipid profile. At levels up to 1.5%-7% of energy, the effect of rTFA seems to be greater than iTFA and it seems to be greater in women. However, rTFA seems to be less harmful than iTFA for High Density Lipoprotein cholesterol, although for total cholesterol and Low density Lipoprotein cholesterol it may be worse. In summary, both sources of TFA can increase cardiometabolic risk parameters, especially lipid profile. However, the dose of TFA and the whole composition of the food must be considered.