Fats

To live a healthy life, living organisms especially humans and animals require a balanced amount of fats in their daily diets. On the basis of sources, there are two types of fats, natural and synthetic fats. On the basis of their structures and chemical properties, they are of two types, saturated and unsaturated fats. Biologically, fats are an important source of energy in humans and animals. Fats are, chemically, triglycerides and they are found in vegetable and animal oils. Though these oils (unsaturated fats) are in a liquid state at room temperature \(25 \degree C)\ when they are hydrogenated, partially or fully, they become saturated fats.

The human body requires both types of fats but in balanced portions. They are also macronutrients and some vitamins are soluble in them. It means that to transport, absorb and digest vitamins in the human body fats are very essential. Fats are a mixture of fatty acids like lauric acid, palmitic acid, stearic acid and many others in different proportions.

Properties of Fats

Chemically, fats are unsaturated and saturated fats. Unsaturated fats are oils whereas saturated fats are, simply, fats. These triglycerides form when three fatty acids combine with glycerol replacing all three alcohol (-OH) groups. The degree of saturation of these triglycerides depends on the carboxylic groups. If carbon atoms in a carboxylic group are saturated with hydrogen atoms then they are saturated oils or fats. These triglycerides are obtained from animals and plants. Animal fats are generally solids whereas vegetable oils are liquid at room temperature. Through the process of saponification, vegetable oils can be saturated. Pure fats and oils are colourless, odourless and tasteless. The colour, taste and odour come from additional foreign substances, lipids.

Hydrogenation or saponification of oils is the process of adding hydrogen atoms to double or triple bonded carbon atoms. Once the saturation completes the oils become fats and their consistency becomes thick. In the controlled process of hydrogenation, such fats are being made which are semisolids and pliable. For cooking food, both oils and fats are useful. Oils and fats are soluble in organic solvents like benzene, ether, chloroform, carbon disulphide etc. but they are not soluble in water and other ionic solvents.

Fats and oils get oxidized at room temperature, become rancid with a disagreeable odour.  To avoid oxidation and suppress rancidity in fats and oils, the addition of antioxidants is the solution. These compounds are added in a very small ratio (0.001% to 0.01%) to fats and oils. Vitamin E is one such antioxidant as well as good to human beings.

The Digestion Process of Fats

Even though fat has gotten a bad reputation but they are very essential for health as the source of energy in humans and other living organisms are fats, carbohydrates and proteins. Fats are the most important among them. When consumed fats are not converted into energy completely during digestion, they are stored in the body. These stored fats are then utilised when extra energy is required by the body like exercise, running and physical activities. The process of digestion of fats involves a series of steps starting from entering the mouth. Teeth in the mouth break the food into tiny pieces and saliva adds moisture to smoothen the process of breaking. Enzymes in the saliva break the fats in the food. This processed food then moves to the stomach through the oesophagus.

The stomach breaks it down further with the help of acids released from the stomach lining. Digestion of major portion fats happens in the small intestine when food moves from the stomach to the small intestine. The pancreas releases enzymes to further break fats, carbohydrates and proteins. Digestive juices complete the process of a complete breakdown of fats and carbohydrates and convert them into packages, chylomicrons.

After complete digestion of fats, fatty acids are passed through the lymph system and then carried away by blood to different parts of the body for utilization like cell repair, cell growth or storage.

Importance of Fats in Human Life

In humans and animals, fats are the source of energy as well as the storage of energy in the body. Breaking of these fats in the cell generates a huge amount of energy and due movements in the body are possible. Fats are also important for maintaining healthy skin, hair, body temperature and insulating organs from shock. Though both unsaturated and saturated fats are good for health recommendation is for unsaturated fats. Saturated fats increase the level of cholesterol in the blood and that causes cardiovascular diseases like a blockage in arteries, other heart-related diseases and heart attacks. Higher intake of fats also affects the mineral density in bones that causes untimely breakage of bones may happen.

In pregnancies, the consumption of fats has both good and bad effects. Controlled and suggested dietary consumption of fats in pregnancy increases the length of gestation and decreases the risk of premature births. On the other hand, an abnormal increase in fat consumption in the diet can cause hypertension and/or preeclampsia during pregnancy.

There are unsaturated fats, monounsaturated and polyunsaturated fats, which are good for health. Monounsaturated fats lower the Low-Density Lipoprotein (LDL) cholesterol levels in the blood and maintain High-Density Lipoprotein (HDL) cholesterol levels. Low levels of LDL reduce the risk of heart-related diseases. Good ratios of monounsaturated fats are in olives and olive oil, avocados and nuts. Polyunsaturated fats of Omega-3 acids are in fish and algae oil abundantly. It also lowers the risk of heart diseases and inflammation by lowering the cholesterol level in the blood. Some of the sources are sunflower oil, safflower, soybean, grapeseed, nuts, etc.

Consumption of fats is also important as several vitamins like A, D and E are soluble and absorbed in fats and are good for a healthy life. It is fact that fats release high energy when burnt in the cells but some fats that are not burnt get converted into body fats.

Frequently Asked Questions on Fats

Q.1: What are the different uses of fats and oils?

Answer: The utilization of fats and oils are in food as well as industrial purposes. There are different forms of fats and oils used in food processing, for example, butter, cooking oils like soybean oil, coconut oil, groundnut oil, rice bran oil, etc. Cod liver oil, fish oil, is a very good source for omega-3 fatty acids, vitamin A and D that reduces the risk of heart diseases and inflammation and provides other health benefits. In industries, fats and oils are useful as lubricants for machines operating at low temperatures, greases, paints, biodiesel, soaps and body care products.

Q.2:  What are the sources of fats and oils?

Answer: In old ages, the two main sources of oils and fats were animals and plants. Nowadays, also they the major sources of fats and oils but due to the high demands, synthetic fats and oils are in the markets. Though these synthetic fats are not useful for food processing purposes they are good for industrial use. Because of these, the production pressure of oils and fats on natural sources has drastically been reduced.

Q.3: Does consumption of fats make a person fat?

Answer: The answer to this problem is not straight. Though fats are very much required to produce energy in the body and due to this, the human body does all the activities. In a normal diet, a portion of fats in the diet acts as a source of energy. But also another portion is stored in the form of fats for emergency use of energy. When this storage of fats becomes high obesity starts to appear. Though fats are not the only reason for obesity it also depends on genetics, sex, age and lifestyle.