Detrimental trans isomers of unsaturated fatty acids

We divide unsaturated fatty acids into cis and trans. They contain at least one double bond of carbon atoms. Depending on the configuration of the atoms in the double bond, we distinguish two isomers.

A substantial body of controlled clinical research definitively confirms that dietary intake of *trans*-isomeric unsaturated fatty acids exerts detrimental effects on blood lipid profiles, primarily by elevating low-density lipoprotein cholesterol while concurrently reducing high-density lipoprotein fractions. Such lipid metabolic disruptions cumulatively amplify the risk of cardiovascular pathologies, including coronary artery atherosclerosis and thromboembolic events. Furthermore, empirical evidence demonstrates that *trans* fatty acids impair tissue insulin sensitivity, thereby disrupting glucose homeostasis and potentially fostering the development of insulin resistance. Their metabolites also induce oxidative stress via excessive generation of reactive oxygen species, accelerating cellular senescence and inflicting DNA damage in spermatozoa, which may correlate with reduced male fertility. Of equal concern is their immunosuppressive activity, which compromises the organism’s defensive responses to pathogenic agents. Particular caution is warranted for pregnant and lactating women—high dietary exposure to these compounds has been epidemiologically linked to elevated risks of fetal developmental abnormalities and a long-term increase in breast cancer incidence (certain meta-analyses report up to a twofold rise in morbidity). From a preventive health perspective, it is critical to deliberately avoid products containing partially hydrogenated vegetable oils (e.g., hardened margarines, ultra-processed confectionery, or fast food), as industrial processes such as catalytic hydrogenation or high-temperature refining are the primary sources of these hazardous isomers.