In this blog post, we'll discuss the difference between saturated and unsaturated fatty acids and what they do.


Triglycerides, a type of lipid, are composed of glycerol and fatty acids. Fatty acids have a molecular structure with hydrogen bonded to a carbon chain, and are categorized into saturated and unsaturated fatty acids based on how the carbons in the carbon chain are bonded to each other.

The carbon bonding form found in saturated fatty acids is a single bond between all of the connected carbons, where each carbon has two hydrogens attached to it. This bond form gives the fatty acid molecule a straight shape, which allows neighboring fatty acid molecules to be tightly connected, resulting in high intermolecular attraction that holds the fatty acid molecules together. It takes a lot of heat energy to loosen this attraction. Fats containing these fatty acids therefore have a high melting point and exist as solids at room temperature. These fatty acid molecules also have enough hydrogen bonded to their carbon chains that the hydrogen is saturated in the molecules, so they are called saturated fatty acids, and the fats they contain are called saturated fats.

The carbon bonding in unsaturated fatty acids is characterized by single bonds between connected carbons and double bonds in some carbon pairs, where the carbons in the double bonded carbon pairs have only one hydrogen bonded to them, unlike the singly bonded carbons. In nature, most unsaturated fatty acids have the hydrogens on the double-bonded carbon pairs connected in the same direction, giving the fatty acid molecule the appearance of a bend at the point where the carbon double bond appears. When there are multiple double bonds, there are also multiple bends, and because of this shape, neighboring fatty acid molecules are relatively distant from each other, resulting in low intermolecular attraction. Fats containing these fatty acids have a low melting point and exist as liquids at room temperature; the higher the number of carbon double bonds, the lower the melting point. Because of this, these fatty acid molecules are called unsaturated fatty acids because the hydrogen in the molecule is unsaturated due to the carbon double bonds, and fats containing these fatty acids are called unsaturated fats.

Saturated fats are deposited around the body's organs to protect them and store them in the body, where they are converted into energy and used to burn calories. However, when this fat binds to low-density proteins, cholesterol is known to build up inside blood vessels, impeding blood flow and increasing pressure inside the vessels, leading to cardiovascular disease. Animal fats such as pork fat, palm oil, coconut oil, and butter are examples of saturated fats, which, when consumed in excess over a long period of time, accumulate subcutaneously and inside organs, causing obesity.

Unsaturated fats help make up the cell membranes of animals. They increase the permeability of the cell membranes, which allows the body to excrete waste and absorb nutrients more easily. They also help to dissolve cholesterol particles on the walls of blood vessels, allowing for better blood circulation. It's also one of the building blocks of the brain and nerve tissue, and long-term deficiencies have been linked to decreased cognitive function, learning ability, and visual function. Sources of unsaturated fats include fish oil, vegetable oils like olive oil and perilla oil, and fats from nuts like peanuts.