Mechanism: How trans fats raise cholesterol?
All food products that contain trans-fatty acids will have to be labeled on the nutritional panel of packaging labels by January 2006. Consuming foods rich in saturated fats and trans-fatty acids are known to raise blood cholesterol and triglycerides, while diets high in unsaturated and polyunsaturated fatty acids do not. When liquid vegetable oils undergo hydrogenation, trans-fatty acids are formed. Because hydrogenated fat is solid at room temperature and has a longer shelf life, it is preferred by food processors. However, considerable evidence suggests that trans-fatty acids raise LDL cholesterol, which can lead to clogging of arteries and heart attack.
There exists a dilemma on the mechanism by which trans-fatty acids raise cholesterol. A recent study by Harvard scientists in the journal Cell sheds light on this issue. The findings suggest that the harmful effects of saturated and trans-fatty acids are set in motion by a biochemical switch by liver cells called PGC-1beta. When activated by trans-fatty acids, this switch sets a cascade of biochemical signals leading to an upsurge in liver’s production of very low density lipoprotein (VLDL) cholesterol the precursors of LDL. By providing evidence of a mechanism through which dietary saturated fats can stimulate hyperlipedemia and atherogenesis, these findings could also open up opportunities for food scientists working on technologies to remove trans-fatty acids from food formulations.