So what are triglycerides? Well, they are fats that the body uses for energy and everybody needs them. But, having too much of them can be detrimental to the body and lead to serious and long term health consequences. High triglycerides are often the result of a lack of physical activity and a poor diet, meaning that reversing these risk factors can have a dramatic impact on keeping the body healthy and thereby reducing the risk of cardiovascular illness and stroke. In fact, those wondering what are triglycerides can sort of consider them one way to measure overall health in terms of diet and exercise levels. Higher levels can indicate a diet that is high in refined and fatty foods or a lack of exercise, and be a means to understand important lifestyle changes that can be made in order to promote better overall health and a reduced risk of disease.
In the intestine , following the secretion of lipases and bile , triglycerides are split into monoacylglycerol and free fatty acids in a process called lipolysis . They are subsequently moved to absorptive enterocyte cells lining the intestines. The triglycerides are rebuilt in the enterocytes from their fragments and packaged together with cholesterol and proteins to form chylomicrons . These are excreted from the cells and collected by the lymph system and transported to the large vessels near the heart before being mixed into the blood. Various tissues can capture the chylomicrons, releasing the triglycerides to be used as a source of energy. Liver cells can synthesize and store triglycerides. When the body requires fatty acids as an energy source, the hormone glucagon signals the breakdown of the triglycerides by hormone-sensitive lipase to release free fatty acids. As the brain cannot utilize fatty acids as an energy source (unless converted to a ketone ), [ citation needed ] the glycerol component of triglycerides can be converted into glucose , via gluconeogenesis by conversion into dihydroxyacetone phosphate and then into glyceraldehyde 3-phosphate , for brain fuel when it is broken down. Fat cells may also be broken down for that reason, if the brain's needs ever outweigh the body's.
Raised triglycerides often go hand in hand with low HDL levels . The higher the triglyceride level the lower the HDL level. Why is this? The explanation is complex, but put simply; as the main triglyceride carrying particles give up their
triglycerides they also transfer cholesterol to HDL . When triglycerides are cleared from the blood less quickly, less cholesterol is transferred to HDL particles meaning HDL cholesterol levels remain low. This is why it is important to have a full lipid profile (total cholesterol, triglycerides and HDL cholesterol), know and understand your numbers.