Other Chemical Processes
In addition, fatty acids are important building blocks of phospholipids and glycolipids that form the phospholipid bilayers out of which all the membranes of the cell are constructed (the cell wall, and the membranes that enclose all the organelles within the cells, such as the nucleus, the mitochondria, endoplasmic reticulum, and the Golgi apparatus).
Fatty acids can also be cleaved, or partially cleaved, from their chemical attachments in the cell membrane to form second messengers within the cell, and local hormones in the immediate vicinity of the cell.
Fatty acids are usually derived from triglycerides or phospholipids.
The Role of Fatty Acids in Your Body
Fat Metabolism
Ketones are a beneficial product of dietary fat metabolism in the body. When carbohydrate intake is restricted, that action lowers blood sugar and insulin levels. As insulin levels fall and energy is needed, fatty acids flow from the fat cells into the bloodstream and are taken up by various cells and metabolized in a process called beta-oxidation.
The end result of beta-oxidation is a molecule called acetyl-coA, and as more fatty acids are released and metabolised, acetyl-coA levels in the cells rise. This causes a sort of metabolic "feedback loop" which triggers liver cells to shunt excess acetyl-Coa into ketogenesis, or the making of ketone bodies.
Once created, the liver dumps the ketone bodies into the blood stream, and they are taken up by skeletal and heart muscle cells at rates of availability. In addition, the brain begins to use ketones as an alternate fuel. That is why everyone can benefit from a Ketogenic diet. Nutritional ketosis is a possible lifestyle option for each of us.
Energy Production
One role of fatty acids within human metabolism is energy production, captured in the form of adenosine triphosphate (ATP).
When compared to other macro-nutrient classes (carbohydrates and protein), fatty acids yield the most adenosine triphosphate (ATP) on an energy per gram basis, when they are completely oxidized to CO2 and water by ß-oxidation and the citric acid cycle.
Fatty acids mobilized from triacylglycerols are oxidized to meet the energy needs of a cell or organism. They are the foremost storage form of fuel in most animals, and to a lesser extent in plants.
Long-chain fatty acids cannot cross the blood–brain barrier and so cannot be used as fuel by the cells of the central nervous system; but medium-chain fatty acids octanoic acid and heptanoic acid can be used, in addition to glucose and ketone bodies.
The processes of fatty acid synthesis (preparation for energy storage) and fatty acid degradation (preparation for energy use) are, in many ways, the reverse of each other.
