Unsaturated fat is a type of fat or fatty acid that is healthy and is, therefore, referred to as the healthy fat. It is a form of lipid, which is a chemical insoluble in water but soluble in some organic solvents such as alcohol, ether, and chloroform.
Along with carbohydrates and proteins, lipids are the main components of plant and animal cells. Cholesterol and triglycerides are examples of lipids.
Unsaturated fats come mainly from plant foods. They stay liquid at room temperature as against saturated fats, which stay solid. These are good or healthy fats, which have health benefits on your body.
- Unsaturated Fats are lipids, which are almost always plant-based. However, certain natural unsaturated fats are present in meat, which also contains saturated fats.
- Unlike saturated fats, which are in the solid state at room temperature, unsaturated fats stay in a liquid state at room temperature and hence are available as oils such as vegetable oils.
- The shelf life of unsaturated fats is only a few days because they spoil or turn rancid early, unlike saturated fats. However, antioxidants help in protecting this rancidity.
- Due to the instability of unsaturated fats, these fats are chemically hydrogenated to increase their shelf life. This hydrogenated unsaturated fat is called Transfat.
- Unsaturated fats are called good fats because they have certain health benefits when consumed.
- They may be monounsaturated fats or polyunsaturated fats depending on their chemical structure.
Plant sources of unsaturated fats
Unsaturated Fats are derived from plants such as:
- Soya bean
How much of unsaturated fats should you consume daily?
According to the U. S. Food and Drug Association, about 30% of your calorie intake can be in the form of unsaturated fats. That is, if you consume 2000 calories per day, you can take about 67 grams of unsaturated fats daily.
The chemical structure of unsaturated fatty acid contains one or more double bonds in the fatty acid chain.
Unsaturated fat has at least one double bond within its fatty acid chain. If it contains one double bond, it is monounsaturated and polyunsaturated if it contains more than one double bond.
Where the double bonds exist, the hydrogen atom is eliminated.
Why Unsaturated fats spoil?
As in saturated fats, unsaturated fats also have a chain of carbon atoms with hydrogen atoms attached. However, certain carbon atoms have a double bond between them. And, where there is a double bond, the hydrogen atom is eliminated.
That double bonded carbon atom is thus unattached and becomes vulnerable to oxidation (called peroxidation) by the oxygen of the atmosphere. This oxidation causes unsaturated fats to spoil or become rancid. The shelf life of the unsaturated is, therefore, only a few days.
List of unsaturated fats
Examples of these good fats include:
- Palmitoleic acid
- Oleic acid
- Linoleic acid
- Myristoleic acid
- Arachidonic acid
Types of Unsaturated Fats
Unsaturated fats are classified according to their chemical structure into:
- Monounsaturated fats
- Polyunsaturated fats
Where there is only one carbon atom with a double bond, it becomes monounsaturated fat.
When there are more than one carbon atoms with a double bond, it is called polyunsaturated fat as shown above.
(A) Monounsaturated Fats
These fats are also called MUFA – Monounsaturated fatty acids. As explained above, they have only one double bond between the carbon atoms.
- Palmitoleic acid
- Oleic acid.
Natural Sources of Monounsaturated Fats
- Whole milk products
- Red meat
- Fruits like olives and avocado
- Oils such as Tea seed oil, Olive oil, Canola Oil, Grape seed oil, Macadamia oil, Groundnut or peanut oil, Sesame oil, Corn oil, Safflower oil, Sunflower oil, Camellia
- Whole Grain wheat cereal
Benefits and Advantages of Monounsaturated Fats
- These fats help in lowering the low-density lipoprotein (LDL) or the bad cholesterol in the blood.
- Help to maintain a healthy lipid profile.
Disadvantages of Monounsaturated Fats
- These fats are more vulnerable to rancidity than saturated fats.
- They are known to increase insulin resistance (makes insulin less effective).
(B) Polyunsaturated Fats
Polyunsaturated fatty acids have more than one double bond between the carbon atoms in their molecular structure. That is, there are more than one carbon atoms, which do not have a hydrogen atom attached to them.
Omega-3 fatty acids and Omega-6 fatty acids are two polyunsaturated essential fatty acids, which are not manufactured by the body and have to be obtained from dietary sources.
Food Sources of Polyunsaturated Fats
- Whole Grain Wheat
- Sunflower seeds
- Hemp seeds
- Peanut butter
- Fish especially wild salmon and fish oil
- Leafy green vegetables
Benefits and Advantages of Polyunsaturated Fats
- Omega-3 fatty acids are known to reduce the risk of heart attacks.
- Omega-6 fatty acids reduce the risk of heart disease.
- Omega-3 fatty acids inhibit the growth of a prostate tumor.
- High levels of Omega-3 fatty acids are associated with the reduced risk of breast cancer.
- Polyunsaturated fat intake reduces the risk of sclerosis.