A Primer on Dietary Fats – Part 2

In A Primer on Dietary Fats – Part 1, I looked at some basic concepts related to dietary fat/lipids including the different primary types of lipid (triglycerides, cholesterol and the ‘other stuff’) as well as the difference between triglyceride and cholesterol.  Finally, I looked at the issue of dietary cholesterol and blood cholesterol briefly.

Today I want to finish up by looking at more detail at the issue of dietary triglycerides.  As I mentioned in Part 1, dietary triglycerides (TGs) make up the bulk of the fat that we consume in a day, providing over 90% of our total fat intake.  Therefore, understanding what the different ‘types’ of TG are along with how they affect the body is important.

 

Types of Dietary Triglyceride

As I mentioned in A Primer on Dietary Fats – Part 1, a fat/TG molecule consists of three fatty acid chains bound to a backbone molecule of glycerol.  And while people tend to talk about different types of fats (e.g. saturated fat or unsaturated fat), it’s actually the specific fatty acids that differ in terms of their chemical structure.  For simplicity, I’ll simply refer to the different types of ‘fats’ and leave it at that.

Things such as chain length, degree of saturation and chemical conformation all go into distinguishing one fat from another but I’ll try to avoid boring people with that level of detail.  Fats are pretty much universally subdivided into four primary categories which are

  1. Trans-Fat
  2. Monounsaturated Fat
  3. Saturated Fat
  4. Polyunsaturated fat

(more…)