Fats are composed of carbon, hydrogen, and oxygen. They  are composed of smaller units. They are composed of smaller units, called fatty acids. Some fats such as groundnut oil, gingelly oil are liquid at room  temperature; some fats such as ghee and butter are solid at room  temperature. Fats are again classified into saturated and unsaturated  fats. In general, animal fats are " saturated "fats; vegetables oils and fats are " unsaturated "fats. Currently  researchers indicate that excessive  intake of saturated fats (i.e., animal fats) is harmful  to the body. Cardiovascular  disease  which    is  a  frequent disease  in the  western  countries , and among the well _ to_ do people in India is attributed to  excessive  consumption  of saturated fats. 


Fats  serve the following  functions:_ 
(1) Dietary  fat is a  concentrated source  of energy. One grm of fat supplies 9 calories of energy. This is almost  twice the number of calories derived  weight for weight, from carbohydrate or protein

(2) Fats are carriers of fat_ soluble vitamins, e.g., vitamins A, D, E and K. 

(3) Dietary  fat supplies " essential  fatty acids". Linoleic acid, one of the essential  fatty  acids, prevents scaly skin formation. In general,  and maintenance  of the integrity  of the skin. 

(4)  The fat layer below the skin plays an  important  role in maintaining  our body temperature. 

(5) Fats provide support for many organs in the body such as heart, kidney,  intestine etc.

(6) Foods containing  fats are tasty.


  Dietary  fats are derived from two main sources _ animal  and vegetable  sources. 

(1) Animal sources   :  These are  ghee, butter, fat of meat, fish oils, atc. 

(2) Vegetable sources : These are various  vegetable oils such as groundnut,  gingelly,  mustard, cottonseed, safflower  ( kardi), and coconut  oil. 

Vanaspati :

When vegetable oils are hydrogenated  under conditions of optimum temperature and pressure  in the presence  of  a catalyst, the  liquid  oils are converted into semi _soild  and solid  fat.  The resulting hydrogenated fat is known as " vanaspati" or vegetable ghee, which is a popular cooking medium in India.

 During the process of hydrogenation, unsaturated  fatty acids are converted into saturated  acids, and the EFA content is drastically  reduced. The  main  advantages of  vanaspati is its ghee_like consistency and its  keeping quality  even in hot humid climates. Since  vanaspati  is lacking in fat_ soluble  vitamins, it isfortified with vitamins A and D by government  regulation  to the extent of  2500 IU of vitamin A and  175 IUof vitamin  D per 100 grams. 

Visible and invisible  fats

 " Visible " fats are those that are separated  from their  natural  source, e.g., ghee ( butter) from milk,cooking oils from oil_ bearing seeds and nuts. It is easy to estimate  their intake in the daily diet. " Invisible " fats are those which are not visible to the naked eye. They are present in almost every article of  food, e.g., cereals, pulses, nuts, milk, eggs, etc. It is difficult  to estimate  their intake. In fact, the major contribution to total fat intake is from invisible sources  rather than visible sources. 

Refined oils 

  Refining  is usually  done  by treatment  with steam, alkali, etc. Refining  and deodourization  of raw oils is done mainly to remove the free fatty acids and rancid materials which may be present in them. Refining  does not bring about any change in the unsaturated  fatty acid content of the oil. It only improves the quality  and taste of oils. Refined oils  are costly. 

Fats requirements 

  In developed countries , dietary fats provide 30 to 40  per cent of total energy intake. The WHO  Expert committee on Prevention  of Coronary  Heart Disease has recommended only 20 to 30 per cent of total dietary  energy  to be provided by fats. At least 50 per cent of fat intake should consist of vegetable oils rich in essential  fatty acids. The Indian Council  of Medical Research  ( 2010) has recommended  a daily intake of not more than 20 per cent  of total energy intake to be provided by fats. 

Fats  and Disease

 Excessive  consumption  of fats results  in obesity,  and disease of blood vessels  ( atherosclerosis). There is high  blood  cholesterol  which is deposited  as plaques  in the arterial  walls; this predisposes  to coronary  artery  disease.  Deficiency  of essential  fatty acids   is associated  with  rough  and dry skin  or road skin ( phrenoderma). The skin is lustreless, and is studded with horny follicles.  In recent years,  there has been some evidence  that Diets  high in fat increase the risk of colon cancer and breast   cancer. 

Types of Fats in body: 

There are different types of fats found in the body, including:

1. Triglycerides: Triglycerides are the most common type of fat found in the body. They are a form of stored energy and are made up of glycerol and three fatty acids. Triglycerides are stored in adipose tissue and can be broken down by enzymes called lipases to release energy when needed.

2. Cholesterol: Cholesterol is a waxy substance that is produced by the liver and is also found in certain animal-based foods. Cholesterol is essential for the production of cell membranes, hormones, and vitamin D. It is transported in the bloodstream with the help of lipoproteins.

3. Phospholipids: Phospholipids are a type of fat that are important components of cell membranes. They consist of a glycerol backbone, two fatty acid chains, and a phosphate group. Phospholipids have a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail, which helps to maintain the structure and integrity of cell membranes.

4. Saturated fats: Saturated fats are typically solid at room temperature and are mainly found in animal products such as meat, butter, and full-fat dairy. These fats are composed of fatty acids that lack double bonds in their carbon chain. High intake of saturated fats has been associated with an increased risk of cardiovascular diseases.

5. Unsaturated fats: Unsaturated fats are typically liquid at room temperature and are found in plant-based oils, nuts, seeds, and fatty fish. They are divided into two types: monounsaturated fats, which have one double bond in their carbon chain, and polyunsaturated fats, which have multiple double bonds. These fats are considered "healthy" fats and can help lower LDL cholesterol levels and reduce the risk of heart disease.

It is important to maintain a balanced intake of fats and choose healthier sources of fats, such as those rich in unsaturated fats, while limiting the intake of saturated and trans fats.


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