Effect of trans fatty acids intake on blood lipid profile

Introduction Trans fatty acids (TFAs) can be expressed as polyunsaturated fatty acids and monounsaturated fatty acids that retain nonconjugated carbon-carbon double bonds in the form of trans and are destroyed by at least one methylene group ( 1). These trans fatty acids are formed by methods known as hydrogenation to produce robust and compliant fats for food manufacturers and consumers (2). Trans fat is becoming increasingly popular in the industrial sector due to its low cost and the possibility to prolong the shelf life of the product and to provide correct functions for foods (3).

For some fatty acids such as trans fatty acids, there are no known deficiencies and even a little ingestion of these fatty acids is associated with the risk of chronic disease. Consequently, traditional DRIs such as estimated mean demand (EAR) and recommended dietary allowance (RDA) do not correlate well with the health effects of these fatty acids. As shown in Figure 4.1, EAR and RDA are based on a U-shaped relationship between nutrient intake and adverse effects (insufficient or other adverse reaction). Therefore, EAR and RDA are not suitable for deficient fatty acids. UL may have a problem as well. For example, in the IOM report on DRI, "UL does not contain trans fatty acids, as I increase intake of trans fatty acid increases CHD risk" (IOM, 2005). UL is defined at levels where intake does not constitute a risk, but trans fatty acids are not.

In addition to trans fatty acids, unsaturated fatty acids have been repeatedly demonstrated to lower blood LDL levels. This effect is most pronounced for polyunsaturated fatty acids (PUFAs) belonging to the Omega 6 family, typified by linoleic acid (found in vegetable oils such as sunflower oil). Thousands of studies have been conducted and broad results have been shown from ineffective heart disease to 40% reduction. Nevertheless, most experts still judge the overall evidence supporting the protective effect of n-3 PUFAs on heart disease, the effect of cardiac dysfunction (atrial fibrillation, arrhythmia) measurement is unknown is there.

Trans fatty acids are derived from raw materials of animals and plants and are produced by partial hydrogenation of unsaturated oils. Dietary intake of trans fatty acids increases low density lipoprotein cholesterol and high intake lowers HDL cholesterol (143-145, 149-151). Metabolic and epidemiological studies indicate that trans fatty acids increase the risk of coronary heart disease (145, 152, 153). Large intake of fat (over one-third of total calories) usually increases the intake of saturated fat and is related to excessive caloric intake and weight gain. Ingesting a small amount of fat (less than 1/10 of total calories) increases the risk of insufficient intake of vitamin E and essential fatty acids and may cause harmful changes in high-density lipoprotein cholesterol and triglycerides (154).

Guidelines for prevention of cardiovascular disease assessment and management of cardiovascular disease risk