Fats/oils are triglycerides {combinations of one glycerol molecule (alcohol family) with three molecules of fatty acids}.

These fatty acids can either saturated or unsaturated. Saturation is dependent on the number of hydrogen atoms attached with carbon atoms back bone carbon chain). If all the carbon atoms are completely saturated with hydrogen atoms then it is termed as saturated fatty acid. If all the carbon atoms are not filled with sufficient hydrogen atoms then the complete chain is termed as unsaturated fatty acid. Unsaturated fatty acids can be monounsaturated or polyunsaturated in nature. However, polyunsaturated fatty acids contain least number of hydrogen atoms.

Saturated fatty acids tend to elevate LDL (bad)  cholesterol. So try to avoid them.

Some important saturated fats are butter, ghee, coconut oil, hydrogenated vegetable oil (vanaspati/dalda) and palm kernel oil.

Unsaturated fats/oils have mono saturated (e.g-oleic acid) and/or polyunsaturated ( e.g. linoleic acid, alpha linolenic acids) fatty acids in different proportions. Some important sources of unsaturated fats are as follows-

a) Plant sources: all the common vegetable oils except coconut oil). IN most of the plant foods and vegetable oils, linoleic acid is predominant PUFA, but mustard and soybean oils, legumes, pulses, fenugreek (methi) seeds and green leafy vegetables are good sources of alpha-linolenic acid.

b) Animal sources: organ meats or flesh foods is mainly composed of cholesteryl esters and phospholipids. They are mainly composed of long chain of linoleic acid(n-6 PUFA). Fish and fish based oils provide long chain alpha-linolenic acid ( n-3 PUFA).

What is cholesterol?

Cholesterol is a soft and  waxy substance found among the lipids (fats), in the bloodstream and cells. It is an essential part of the healthy body because it is used to form cell membranes and hormones. On the other hand a high level of cholesterol in the blood (hypercholesterolemia) is a major risk factor for coronary heart diseases and leads to heart attack.

Cholesterol and other fats can not dissolve in the blood. They have to be transported to and from the cells by special carriers called lipoproteins( lipids proteins). They are of several kinds, but the most important are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).

What is LDL-cholesterol?

Low-density lipoprotein is the most important cholesterol carrier in the blood. If surplus LDL cholesterol circulates in the blood, it can slowly assemble up in the walls of the arteries, which are suppling blood to heart and brain. In association with other substances (like platelets, monocytes and macrophages) it can form a plaque, a thick, hard deposit that can clog these arteries. This condition is known as atherosclerosis. A clot (thrombus) that forms in the region of this plaque can block the flow of blood to part of the heart muscle and cause a heart attack. If a clot blocks the flow of blood to part of the brain, the result is a stroke. A high level of LDL cholesterol (160 mg/dL and above) reflects an increased risk of heart disease. Due to this LDL cholesterol is often calledbadcholesterol. Lower levels of LDL cholesterol reflect a lower risk of heart disease.

What is HDL-cholesterol?

25-35% of blood cholesterol is carried by high-density lipoprotein or HDL. It has been observed that HDL tends to carry cholesterol away from the arteries. In this manner HDL removes excess cholesterol from atherosclerotic¬† plaques and thus slows their growth. Therefore HDL cholesterol is known as “good” cholesterol. A high level of HDL has protective effect on heart attack. The lower HDL values (less than 40 mg/dL) indicates a greater risk of heart attacks and strokes.