Fats, fatty acids and triglycerides.
Fats are compounds which, like carbohydrates and proteins, are  consisted of oxygen, hydrogen and carbon and they are equally vital dietary sources with the other two groups, in terms of nutrition. The chemical structure and the number of oxygen atoms contained in the molecule make the difference between these three categories. For instance, fats contain proportionally more carbon and hydrogen and far less oxygen than carbohydrates.
Contrary to common notion, the words fats and lipids are not synonyms. Lipids are a broader group of biochemical molecules and fats, along with waxes and terpenes, are included in this group. Lipids are soluble in solvents, like alcohol, ether and chloroform, but they are practically insoluble in water.
Fats are the most condensed sources of energy. One gram of fats provides nine calories, whereas the same amount of carbohydrates or proteins
supplies
four calories, when utilized in the body. As soon as the body has consumed the calories from available carbohydrates, it begins to depend on the energy derived from fats. This happens after the first stage of an anaerobic exercise session.
Fatty acids are the basic units of fats. The latest are stored in the body as triglycerides which are multi-molecules consisted of three fatty acids each. Although the significance of blood triglycerides level has not been totally identified yet, specialists recommend that it should be lower than 150mg/dL. Certain groups of fatty acids are absolutely necessary for optimum function of organs or systems, although they are not synthesized within the body. Thus, they must be obtained from foods and are classified as essential. Alpha-linolenic and linoleic are the two essential fatty acids and they are included in the omega-3 and omega-6 relevant categories respectively.
Fat tissue plays a key role in maintenance of healthy skin and hair. It also contributes to proper insulation and protects the body from reasonable external temperature fluctuations. Moreover, fat tissue provides the necessary cushioning and protection to organs, whereas fatty acids promote healthy cellular function and control blood cholesterol levels. Vitamins A, D, E, and K are fat-soluble. Thus, they can only be ingested and processed in conjunction with fats.
Lipolysis is a metabolic process and involves the decomposition of triglycerides to fatty acids and glycerol. The latest can be converted to glucose within the liver which, in turn, is used as a source of energy.
According to their chemical structure, fats are classified as saturated, unsaturated and trans ones.
Saturated fatty acids.
Saturated are fats contained in pork, beef, lamb, poultry  skin, whole-fat dairy products, some seafood and egg yolks. In general, saturated fats are typically found in animal-derived products but there are a few exceptions. For instance, oils extracted from coconut or palm kernel contain saturated fats too.
Diets rich in saturated fatty acids have been associated with high blood cholesterol levels which, in a long term, may result in cardiovascular disease. The condition includes atherosclerosis, high blood pressure, angina, coronary heart disease and stroke. However, it has to be clear that diet affects bad cholesterol level only by 25%. The rest 75% is produced in the liver.
Although more thorough studies may be needed, there is strong evidence that prolonged and increased intake of dietary fat can elevate the risk for prostate cancer and if the same diet is poor in fiber, the risk for colorectal cancer increases significantly.
Unsaturated fatty acids.
Unsaturated are fats that are found in plant origin foods and they  seem to provide better control of cholesterol metabolism. They promote the synthesis of high-density lipoprotein (HDL), which is better known as good cholesterol, and interfere with the production of low-density lipoprotein (HDL) that is often referred to as bad cholesterol. Researchers have concluded that if unsaturated replace saturated fats in a person's diet, they can easily reduce the risk for cardiovascular disease by 40%.
There is a simple rule about fat foods. If unsaturated fatty acids prevail, the food is in oily form. On the other hand, in foods rich in saturated fats, the consistency is buttery in room temperature. The exceptions include very limited number of oils, such as those derived from coconut or palm. As it has been mentioned already, these oils contain saturated fats.
Unsaturated fatty acids are classified as mono-unsaturated and poly-unsaturated, depending on their chemical structure. Olive, canola and peanut oils are the most characteristic examples of mono-unsaturated fats. The prevention of coronary heart disease and the anti-cancer properties of the olive oil have been broadly acknowledged.
Polyunsaturated fats are included in high concentrations in sunflower, safflower, corn and soybean oils.
Hydrogenated oils.
Hydrogenation is a technical process in which one or more atoms of hydrogen are added in the molecule of an unsaturated fatty acid. This hydrogen addition renders the fat saturated. The method is used, in order vegetable oils to be transformed from liquids to margarines which present a soft or hard butter texture. A lot of hydrogenated oils are used in food industry, because they give characteristic properties to the products. For instance, the firmness of vegetable whipped creams, the spreadability of margarines or the crispiness of French fried potatoes are due to the use of hydrogenated fatty acids. Moreover, processed foods containing hydrogenated fats have a more extensive consumption life and can stay on the shelf for longer time.
It is apparent that hydrogenated oils must be consumed rarely and in moderation, since they act like saturated fats and can cause very similar health problems. Essential fatty acids contained in oils, get destroyed, during hydrogenation.
Trans fatty acids.
These are unsaturated fatty acids with altered structure of their chemical chain. Trans fatty acids, although  they are present in natural dairy products, beef and lamb, they typically occur during partial oil hydrogenation and production of processed foods. Cooking in very high temperature can result in trans fat formation.
Snacks, fried foods, a wide range of commercial baked goods, margarines and other processed foods are very likely to contain increased amounts of trans fatty acids.
Researchers claim that trans fats are more harmful than the saturated ones and they are strongly related to high blood cholesterol levels and cardiovascular conditions. What is more, studies have given evidence that trans fatty acids are associated with obesity, metabolic syndrome and diabetes. |
