Food items such as eggs, vegetable oil, walnut, fish and milk all vary greatly from each other. Do these items still have anything in common? The answer to this question is ‘Yes’. Lipids are the ones arousing a sense of similarity between them.
Lipids are the group of organic compounds like fats, mono-glycerides, di-glycerides, tri-glycerides, fat soluble vitamins (A, D, E and k) and some components of membranes which usually do not react with water but yet they group together. In other words, Lipids may be defined as the molecules containing hydrocarbons and making up the building blocks of the structure as well as the function of the living cells. Lipids generally are non-polar and hence they are only soluble in non-polar environment like Chloroform. Water providing a polar environment becomes unsuitable for dissolution of lipids into it. They generally exist in highly reduced form of carbon and when metabolised, even releases a huge amount of energy. They are extracted from plants and animals with the help of non-polar solvent. Lipids normally fit into four subcategories which are fatty acids, triacylglycerol, phospholipids and steroids. The most common form of lipids is fats. They are the organic compound usually made up of hydrogen, oxygen and carbon. In adipose cells, a type of connective cell, triglycerides are isolated in the form of fats. Fats are the energy storage molecules and also provide thermal insulation to body hence justifying their presence. Also, some lipids are assigned the job of transferring various chemical messages between different cells, tissues and organs. Yet another type of lipid called phospholipid has two layers which forms microscopically thin membrane of the cells. These phospholipids allow the fat and water to mix through it thin membrane which thus allows the fat to act as a part of blood and move with it in and out. Most of the lipids function as energy storage and in the formation of membranes too. They even function as intercellular as well as extracellular message carriers.
Lipids although are the very important nutrients that the body needs in order to function properly but when consumed in excess many lipids specially the saturated fats and trans fats which are unhealthy by nature leads to a numerous heart diseases , cancer and even obesity.
These saturated fatty acids are judged to have negative health impact due to the increase in the serum cholesterol level which they are held responsible for. Mono saturated fatty acids on the other hand is believed to have a good impact on health as it leads to decreased LDL oxidation which in turn helps to control the diabetes. But a thing to be cautious about is that such mono saturated fatty acids must be the ones extracted from plant oil like olive oil and not from food which are mainly rich in saturated fatty acids welcoming various diseases. The fatty acids composition in the food should rather be optimized to produce benefitting results.
The most important role of lipid is provision of energy. Interestingly, most of the energy that a human body needs is provided by the process of oxidation of lipids and carbohydrates. A carbohydrate acting as easily available source of energy, although has a lesser role to play as compared to lipids. Lipids are the actual and the primary energy reserve for a human body and even are the sole energy reserves for the hibernating animals and migrating birds. The amount of energy stored in lipids even exceeds the energy stored as glycogen by a great amount. Data reveal that Lipids is the source of about 9 kcal of energy per gram whereas the carbohydrates and proteins are able to yield only 4 kcal of energy per gram. The Lipid reserves however, are alone sufficient to make the human body function for about 30-40 days without any food. Lipids hence yielding a far greater amount of energy truly justify being entitled with energy reserves of body.
Moreover, lipids also have an important role to play in the absorption as well as the storage of many essential vitamins. The vitamins such as A, D, E and K which are all fat soluble completely rely on lipids for their absorption, their transportation and the storage in the human body. If the consumption of fat soluble vitamin exceeds the requirement of the body, the extra vitamins are stored with lipids for future use. The storage of these fat-soluble vitamins with lipids helps maintain one’s vision and bone density. It even helps to strengthen the immune system. Also, it plays a major role in keeping the heart healthy and helps blood clotting.
Monounsaturated fats, yet another kind of lipid too has numerous health benefits associated with it. These fats have recorded to show improvement in one’s blood cholesterol levels. They mainly lower the level of LDL cholesterol and increasing the level of HDL cholesterol in the blood. The LDL cholesterol is considered to be bad cholesterol whereas HDL is considered as good cholesterol as it has been benefitting the humans. An improved cholesterol profile reduces the risk of heart disease and lipids playing an important role thus prove its significance.
However, for enjoying the actual benefit of the lipids one must be cautious about the amount that is being taken in. An excess of everything is bad and same is the case with lipids. There must be a control on their intake else they instead of benefitting would cause harm to health.
Lowering the saturated fat will likely have no benefit if they are replaced with refined carbohydrates. Ironically, substituting the refined carbs for saturated fat does lower “bad” LDL cholesterol but it too decreases the level of “good” HDL cholesterol and thus increases triglycerides. The net effect therefore is even worst. Also, consuming high dosage of lipids results into obesity which in itself is a root cause for many diseases.
Lipids although have a numerous benefitting effects but if consumed in excess they even can turn out to be a fatal weapon. The positive effects of lipids are surely strong enough to overshadow the negative impacts, provided they are consumed with caution.
References
Education Portal, (2014). Health Effects Associated with Lipids - Video & Lesson Transcript | Education Portal. [online] Available at: http://education-portal.com/academy/lesson/health-effects-associated-with-lipids.html#lesson [Accessed 9 Nov. 2014].
Lipids?, W. and Cashin-Garbutt, A. (2009). What are Lipids?. [online] News-Medical.net. Available at: http://www.news-medical.net/health/What-are-Lipids.aspx [Accessed 9 Nov. 2014].
U, W. (2014). What are the health effects of fat? - PubMed - NCBI. [online] Ncbi.nlm.nih.gov. Available at: http://www.ncbi.nlm.nih.gov/pubmed/15052493 [Accessed 9 Nov. 2014].
