Fatty Acids

Structures of Fatty Acids

Fatty acids are components of triglycerides. They are like the brick in a brick wall. Each individual brick is needed to make the overall wall. There are two basic types of fatty acids:

  • saturated fatty acid
  • unsaturated fatty acid

These molecules differ in structure and food sources.

Saturated fats are linear in structure while unsaturated fats are bent in appearance. Saturated fatty acids exhibit a linear structure while unsaturated fatty acids bend, or kink, due to double bonds within the chemical foundation.

Saturated Fatty Acids

The term saturated means filled to capacity; for example, a saturated sponge cannot hold more water.

In relation to fatty acids, this refers to the chemical structure of the fatty acid itself.  The primary components of fatty acids are carbon, hydrogen, and oxygen.  When carbon atoms bond together, they form a single bond and can exhibit a zig-zag shape.  When the overall molecule is seen, the entire fatty acid appears as a fairly straight line.  In this orientation many saturated fatty acids may line up side by side, similar to soldiers standing at attention.  This formation causes saturated fatty acids to pack together very tightly which is why they are solid at room temperature.  Think of a stick of butter.

In fatty acids, each carbon can only have two adjacent hydrogen atoms.  When all of a fatty acid's carbons have their capacity of hydrogen atoms, they are called saturated fatty acids.

The chemical structure of a saturated fatty acid exhibiting single bonds between each carbon atom. The chemical structure of a saturated fatty acid exhibits each carbon bonding to the adjacent carbon with single bonds. Each carbon is also bonded to two hydrogen atoms.

Several saturated fatty acids can tightly pack together due to their linear chemical structure. The linear nature of saturated fatty acids allows for tightly packed formations, causing them to be solid at room temperature. Hydrogen atoms are not represented in this image, but are, indeed, present in fatty acid molecules.

Unsaturated Fatty Acids

There are some types of fatty acids that have carbon atoms that bond twice to other carbon atoms.  This is called double-bonding.  When this occurs, the linear orientation of the overall molecule is bent, or kinked, as the double-bond pulls differently between the atoms involved.  These bends prevent neighboring fatty acids from forming the tight, side-by-side grouping that is seen in saturated fatty acids.  Because they are spaced apart, these fatty acids form liquid fats, typically called oils, at room temperature.

Unsaturated fatty acids have double bonds between carbon atoms. This causes them to bend or Unsaturated fatty acids have at least one double bond between carbon atoms. This causes them to have one less hydrogen atom and allows for bending of the overall molecule.

Unsaturated Fatty Acid Bent

Unsaturated Spaced Formation


There are two essential fatty acids, which are:

  1. linoleic acid (omega-6)
  2. alpha-linolenic (omega-3)

These fatty acids are essential because the body cannot synthesize them.  The essential fatty acids are critical to human health as they play important roles in every system of the body.

Good food sources of omega-6 include whole grains, fresh fruits and veggies, fish, olive oil, and garlic.

Good food sources of omega-3 include flax seed, egg yolk, and chia seeds.

FYI: Trans-fatty acids - like Crisco- are hydrogenated vegetable oils. In an artificial chemical process hydrogen is added to natural vegetable oils to make them more solid at room temperature, and more heat resistant for cooking. Hydrogenated oils are more resistant to heat degradation. The body doesn't have an efficient process for using trans-fats, so they get stored for the long term.

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