FAT IS NOT BAD!!!!

In continuation of my articles on Macro-nutrients, let's discuss fats as another macro-nutrient which is as important for the body as oxygen to breath.

Actually, the macro-nutrient is LIPIDS which is a combination of Triglycerides and many other components commonly known as fats. The structure is made up of Carbon, Hydrogen and Oxygen.

Energy output

Calorific value of 1 gram fat is 9 calories.

Composition

As I mentioned in my previous article about the composition of carbohydrates which are made of Glucose, similarly lipids are made of fatty acids. Based on the bonding between carbon atoms, the fatty acids are of two types namely - 

1. Saturated fatty acids - single bond among all carbon atoms
2. Unsaturated fatty acids - a) Monounsaturated - one double bond among carbon atoms.                                                            b) Polyunsaturated fatty acids - Multiple double bonds.

Functions

Fats are useful for many functions in the body which we will continue to notice in this article to justify the title. Some of them are - 

• Fats are required for normal functioning of brain.
• For proper physical growth of an individual.
• For proper development and functioning of immune system.
• For most of the metabolic activities.
• Fats are major source of fuel during exercise.
• Fats are essential for absorption of Vitamin A,D,E,K which are fat soluble vitamins.
• Body fat provides cushioning to vital organs.
• All cell membranes and cell structures have fat as component.

Types of Lipids (Not-Important, meant only for curious readers)

• Fatty acids - basic unit of lipids.
• Triglycerides - 98% of all fats in the body. Triglycerides from food are stored in the adipose tissues which releases fatty acids for fuelling muscles at rest.
• Essential fatty acids - a) Linolenic acid, b) Alpha-linolenic acid(ALA), c) Gamma-linolenic acid(GLA). Essential fatty acids are required for general health of the body.
•  Omega-3 fatty acids - a) EPA - Eicosapentaenoic acid, b) DHA - Docosahexaenoic acid and MCTs -medium chain triglycerides.
• Phospholipids - Transportation of lipids.
• Lecithin - Acts as emulsifier.
• Sterols including CHOLESTEROL.

CHOLESTEROL

Cholesterol is one of the most dreaded compound discussed in relation with heart diseases only but in this article we shall get to know how important and critical cholesterol is for our body and its functioning. 

Cholesterol is a type of lipid but different in structure as compared to other lipids. It has a ring structure and doesn't have fatty acids and glycerol in it which are predominantly found in all lipids.

Most Important fact - Human body can produce all the cholesterol it needs.

Cholesterol is found only in animal products like eggs, meat, whole milk etc. Let's discuss the functioning of cholesterol in human body - 

1. Cholesterol is required to produce and sustain certain vital hormones.
2. Used for making bile acids required for digestion of fats.
3. It is a component of all cell structures.
4. Precursor to vitamin D. (read my article on vitamin D)
5. Production of various sex hormones and adrenal hormones.
6. Essential for brain health and nervous system.

Relation with heart diseases - Cholesterol is considered as the main culprit when cardiovascular diseases are discussed but the truth is the total cholesterol count is taken in to consideration whereas ratio of HDL to LDL should be taken to judge the cholesterol levels. HDL and LDL to be discussed later in the article.

HOW FOOD GETS CONVERTED TO FAT???

Digestion of fats consumed in food starts in the stomach through an enzyme called lipase but only short chain fatty acids gets broken here. Majority of digestion takes place in small intestine in the presence of pancreatic lipase where triglycerides are broken in to glycerol and fatty acids. In the presence of bile secreted by liver in small intestine the digestion takes place at a rapid pace. Cells in small intestine absorbs these fatty acids and are ready to be transported to other parts of the body including the adipose tissue for storage.

Since fats are not water soluble transportation through blood or lymph is difficult and here comes the LIPOPROTEINS in the picture. Lipoproteins are specialised structures with a core of lipids and layered with protein, phospholipids and cholesterol.

These lipoproteins transport fats from liver and intestines to our body. There are 4 types of lipoproteins -

1. Chylomicrons - Carries dietary fats to muscle tissues.
2. VLDL - Very Low Density Lipoprotein - It converts in to LDL after releasing glycerol and fatty acids in the blood stream.
3. LDL - Low Density Lipoprotein (also known as bad cholesterol) - It transports cholesterol to the body.
4. HDL - High Density Lipoprotein (also known as good cholesterol) - It transports all the cholesterol from dying cells to the liver.

I believe the concept of HDL and LDL is clear and its relation to cardiovascular diseases as well.

ADIPOSE TISSUE

Adipose tissues are basically fat storing cells and have the capacity to increase in size up to 50 times of their initial size. They can also multiply in numbers in order to absorb additional fat. Adipose tissues stores fats as triglycerides and release fatty acids to supply energy to the body at rest.

SUPPLEMENTATION -  

The most important and well researched supplement of fatty acids is FISH OIL. Fish oil is rich in omega-3 polyunsaturated fatty acids. Fish oil supplementation helps in improving metabolic efficiency.

Fish oil also helps in reducing triglyceride levels and reducing body fat, heart diseases and lowering of blood pressure. Fish oil also helps in muscle building.

CONCLUSION - As per popular belief, fats are not at all bad for our body, in fact they are the most crucial macro-nutrient required for normal functioning of our body. Fat is not bad at all!!!

Ref:- INFS course book.